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Margerison, Jean K. "Restricted suckling and nutrition of dairy cattle." Thesis, Bangor University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296323.
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Olynk, Nicole J. "Economic analyses of reproduction management strategies and technologies on U.S. dairy farms." Diss., Connect to online resource - MSU authorized users, 2008.
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Thesis (M.S.)--Michigan State University. Dept. of Agricultural, Food, and Resource Economics, 2008.Title from PDF t.p. (viewed on July 28, 2009) Includes bibliographical references (p. 105-108). Also issued in print.
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Hamudikuwanda, Humphrey. "Endocrine and metabolic mediators of dietary energy status and reproduction in dairy cows." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28770.
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Five experiments were undertaken to identify metabolites and hormones that could mediate the effect of dietary energy status on reproduction, particularly pulsatile secretion of luteinizing hormone (LH) postpartum dairy cows.In the first two experiments, the concentration of progesterone (P4) in tailhead adipose tissue and plasma in 12 cows at different stages of pregnancy and lactation was determined as was P4 produced in vitro by explants of tailhead adipose tissue. Concentration of P4 in adipose tissue was correlated with that of plasma P4 near estrus and during the luteal phase of the estrous cycle, and P4 was released in vitro by fat mobilization.
In the third and fourth experiments, blood was collected continuously for 16 h from four ovariectomized cows offered maintenance or restricted energy diets after priming with P4 or estradiol (E2) using a crossover experimental design. The results indicated that P4 released during body fat mobilization is minor and is not related to LH secretion. Dietary energy restriction influenced plasma LH concentration and pulse amplitude but the effect was modulated by P4 and E2 priming. Dietary energy restriction decreased glucose concentration but did not influence plasma non-esterified fatty acids (NEFA), cortisol, P4 and insulin levels. Cortisol was negatively related to LH pulse frequency. Glucose and insulin were positively and negatively correlated with LH pulse amplitude, respectively. Cortisol, NEFA and glucose jointly had a negative correlation with LH concentration.
In the fifth experiment, blood samples were collected daily for 60 d and every 10 min for 8 h on 18, 36 and 54 d postpartum from 24 cows (12 ovariectomized) fed low (1.4 Mcal/kg DM) (L) or high (1.7 Mcal/kg DM) (H) energy in a 2 x 2 factorial treatment design. LH pulse frequency was reduced at 18 d postpartum in ovariectomized cows, but not in intact cows, fed L. First postpartum ovulation occurred later in intact cows fed L compared to those fed H. Energy balance and plasma glucose concentration were lower, but plasma NEFA, $ beta$-hydroxybutyrate (BHB) and E2 concentrations higher, in cows fed L compared to those fed H. E2 concentration in intact cows fed L was elevated for a prolonged period prior to first ovulation. Diet had no influence on plasma P4 and insulin concentrations. Plasma E2 and BHB concentrations were positively correlated with LH pulse frequency in intact cows across diets and ovariectomized cows fed L, respectively. NEFA were negatively correlated with LH pulse amplitude in ovariectomized cows fed L. Glucose, NEFA and P4 were negatively, but BHB, E2 and insulin positively correlated, individually or in association, with LH concentration.
Overall, the results suggest that the effect of dietary energy status on LH patterns and timing of onset of postpartum ovulation is modulated by priming with or presence of ovarian steroids. The relationships of metabolites and hormones with LH patterns appear to change with dietary energy level, ovarian status and mutual associations among the metabolites and hormones. These parameters, especially glucose and BHB, may be potential mediators of the effect of dietary energy status on LH patterns. (Abstract shortened by UMI.)
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Larcombe, Michael Tinniswood. "The effects of manipulating reproduction on the productivity and profitability of dairy herds which graze pasture /." Connect to thesis, 1989. http://eprints.unimelb.edu.au/archive/00000650.
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Voelz, Benjamin. "Heat stress and uterine disease: Stressors influencing reproduction of dairy cattle." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/36195.
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Doctor of PhilosophyDepartment of Animal Sciences and Industry
Luis G. Mendonca
Reproduction is an important part of a dairy operation that directly affects milk production and profitability. Fertility of high-producing dairy cows is less than desired. Reproductive efficiency is further impaired during summer months and after cows develop postpartum uterine disease. Heat stress and uterine disease act as stressors that negatively influence fertility of dairy cattle through a variety of mechanisms. This dissertation further investigates the negative effects of heat stress and uterine disease on reproduction, as well as examines two potential markers for predicting risk of developing uterine disease. Study 1 investigated the treatment of lactating dairy cows with gonadotropin-releasing hormone (GnRH) before first insemination during heat stress. Two experiments were performed to compare ovarian responses, pregnancy per artificial insemination (AI), and patterns of insemination of two estrus detection-based presynchronization protocols before first AI during summer heat stress. Treatment of cows with GnRH during summer heat stress altered ovarian response and pattern of insemination, however, did not improve pregnancy per AI. Study 2 evaluated ovarian response to treatment with GnRH and the odds of bearing a corpus luteum or being inseminated in cows with or without purulent vaginal discharge (PVD). Furthermore, hazard of insemination after administration of prostaglandin F2α was evaluated in dairy cows with or without PVD. Ovarian response was altered in cows with PVD compared with cows without PVD. Odds of bearing a corpus luteum or being inseminated was not associated with PVD in primiparous cows, whereas it was associated with PVD in multiparous cows. Hazard of insemination after prostaglandin F2α was not associated with PVD. Study 3 investigated arginase and matrix metalloproteinase-8 (MMP-8) as potential markers for metritis. Activity of arginase 7 days before parturition has been identified as a potential marker for the risk of developing metritis in dairy cows. In contrast, MMP-8 was not associated with the risk of developing metritis, therefore, MMP-8 is not a good candidate as a marker for metritis. Further research is warranted in the areas of reproductive physiology, heat stress, and uterine disease because several unanswered questions still exist. Improving fertility during times of heat stress and after the occurrence of postpartum uterine disease will improve milk production, animal welfare, and profitability of dairy farms across the world.
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Gallo, Guillermo Federico. "Effects of exogenous recombinant bovine somatotropin on reproduction and nutritional status of dairy cattle." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74303.
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Long-term administration of recombinant bovine somatotropin (rbST) significantly increased milk and 3.5% fat-corrected milk production without altering milk composition. These effects occurred regardless of breed, parity or drug delivery system (daily or sustained-release) utilized. Somatotropin did not affect apparent digestibility of rations, dry matter intake, crude protein intake, energy intake or energy balance. Body energy reserves, measured as body condition scores, decreased during rbST treatment resulting, together with the increase in milk yield, in an improvement of the efficiency of conversion of feed to milk for cows treated with rbST. Body condition was completely regained during the dry period. No effects of rbST on mastitis or metabolic diseases were observed. During lactation, injection of rbST produced elevated circulating concentrations of non-esterified fatty acids, glucose, insulin, bST and IGF-I but lipid composition of liver and ketogenic functions were not altered. These lipolytic and diabetogenic activities might contribute to the galactopoietic response elicited by rbST. Somatotropin did not modify the nutritional status of cows during pregnancy or the nutritional status and growth rate of their calves from birth to weaning.With regard to reproduction, somatotropin augmented ovarian progesterone production during the first two estrous cycles post-injection and during gestation. These effects may have been mediated through increased ovarian IGF-I synthesis. Somatotropin enhanced the GnRH-induced LH response at 14 d postpartum. In spite of these positive observations, somatotropin treatment tended to produce longer calving to conception intervals. Nevertheless, the higher persistency of milk production by cows treated with rbST may compensate for this difference economically.
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Truman, Carissa Marie. "AUTOMATED BODY CONDITION SCORING: PROGRESSION ACROSS LACTATION AND ITS ASSOCIATION WITH DISEASE AND REPRODUCTION IN DAIRY CATTLE." UKnowledge, 2019. https://uknowledge.uky.edu/animalsci_etds/96.
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Body condition scoring is a technique used to noninvasively assess fat reserves. It provides an objective estimate to describe the current and past nutritional status of the dairy cow and has been associated with increased disease risk and breeding success. Traditionally body condition scores are taken manually by visual appraisal on a 1 to 5 scale, in one-quarter increments. However, recent studies have shown the potential of automating the body condition scoring of cows using images. The first objective was to estimate the likelihood of disease development and breeding success, using odds ratios, associated with body condition score scored automatically at various points in lactation. The second objective of our research was to use a commercially available automated body condition scoring camera system to monitor body condition across the lactation period to evaluate differences between stratified parameters and to develop an equation to predict the dynamics of the body condition score. We found that poor body condition score at different times during the transition period are associated with increased disease occurrence and lower reproductive success. Automated body condition scoring (ABCS) curve during lactation was influenced by many factors, such as parity, ABCS at time of calving, disease occurrence, and milk production.
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Lefebvre, Daniel Maurice. "Studies on the effects of recombinant bovine somatotropin on nutritional status and reproduction of dairy cows." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0003/NQ44488.pdf.
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Clempson, Andrew. "Associations of genetic polymorphisms with growth, fertility and production traits in UK dairy cattle." Thesis, Royal Veterinary College (University of London), 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558960.
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Halbach, Theodore John. "SEASON AND LACTATION NUMBER EFFECTS ON PRODUCTION AND REPRODUCTION OF DAIRY CATTLE IN ARIZONA (AGE)." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275354.
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Tutusaus, Batlle Joan. "Clinical aspects of C. burnetii infection in dairy cattle." Doctoral thesis, Universitat de Lleida, 2014. http://hdl.handle.net/10803/146131.
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La febre Q és una zoonosis re-emergent endèmica mundialment, causada per Coxiella burnetii, un bacil Gram negatiu intracel.lular. Els remugants domèstics són el reservori principal per als humans. La infecció és principalment asimtomàtica en boví, però se l’ha relacionat amb desordres reproductius. L’objectiu d’aquesta tesis ha estat proporcionar informació per millorar el seu control a les explotacions bovines. S’han estudiat la serologia, els patrons d’excreció de C. burnetii i la seua relació amb el rendiment reproductiu de les vaques lleteres. A més, s’ha evaluat la bioseguretat d’una vacuna inactivada contra C. burnetii fase I aplicada en vaques gestants i la seua capacitat per millorar el rendiment reproductiu. Les conclusions són que no s’han detectat anticossos precalostrals en vedells de mares infectades, l’excreció i la seropositivitat no es relacionen negativament amb el rendiment reproductiu i que la vacunació de vaques en gestació avançada no redueix l’excreció però millora el rendiment reproductiu.La fiebre Q es una zoonosis re-emergente endémica mundialmente, causada por Coxiella burnetii, un bacilo Gram negativo intracelular. Los rumiantes domésticos son el reservorio principal para los humanos. La infección es principalmente asintomática en bovino, pero se la ha relacionado con desórdenes reproductivos. El objetivo de esta tesis fue proporcionar información para mejorar su control en las explotaciones bovinas. Se estudiaron la serología, los patrones de excreción de C. burnetii y su relación con el rendimiento reproductivo de las vacas lecheras. Además, se evaluó la bioseguridad de una vacuna inactivada contra C. burnetii fase I aplicada en vacas gestantes y su capacidad para mejorar el rendimiento reproductivo. Las conclusiones son que no se detectaron anticuerpos precalostrales en terneros de madres infectadas, excreción y seropositividad no se relacionaron negativamente con el rendimiento reproductivo y que la vacunación de vacas en gestación avanzada no reduce la excreción pero mejora el rendimiento reproductivo.
Q fever is a worldwide re-emerging zoonosis caused by an intracellular Gram negative bacillus, Coxiella burnetti. Domestic ruminants are the main reservoir to humans. Despite the infection is mainly asymptomatic in cattle, is has been linked with reproductive disorders. Therefore, the aim of this thesis was to provide information about C. burnetii infection to improve its control in dairy herds. A study of serological profiles, shedding patterns and its relationship with reproductive performance has been performed. In addition, a C. burnetii inactivated phase I vaccine has been tested evaluating the biosafety for use in pregnant cows and in assessing its ability to improve reproductive performance in dairy herds. The results indicate no detectable precolostral antibody response in calves born from infected dams, seropositivity and shedding are not related to reproductive disorders and vaccination of advanced pregnant cows was not able to reduce bacterial shedding but improves reproductive performance.
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Swangchan-Uthai, Theerawat. "Molecular response of the endometrium to bacterial infection in dairy cattle." Thesis, Royal Veterinary College (University of London), 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.572492.
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Tollefsrud, Ryan Peder. "Effects of fresh-cow diseases on reproduction in a large commercial dairy herd." Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/14067.
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Master of ScienceDepartment of Clinical Sciences
Bob L. Larson
The 2007 NAHMS (National Animal Health Monitoring System) survey indicated that early lactation health issues are major factors influencing reproduction and culling on U.S. dairy herds. The objective of this study was to evaluate fresh-cow health during the first 30 days in milk, and its association with days to pregnancy in the concurrent lactation. Data were collected on cattle that calved over a two month period (July and August 2009) on a dairy farm located in the Upper Midwest region of the U.S. Health and production data were collected daily for each cow from the beginning of lactation until the majority of the study population was confirmed pregnant. Both a competing risk analysis and a semi-parametric Cox regression model were used to test the association between specific health-related events and days to pregnancy and the outcomes of the two models were compared. These analyses showed metritis and dystocia in the first 30 days of lactation were associated with greater days to pregnancy. The only difference noted between parities was that lactation-five and greater cows were significantly associated with greater days to pregnancy. The two analyses showed conflicting significance of association between retained placenta, ketosis, twinning, lameness, and other non-specific illnesses with days to pregnancy. This study found that a competing risk analysis and a semi-parametric regression model were appropriate methods to analyze time sensitive data such as reproductive efficiency. This study supports the evidence that parity, metritis, retained placenta, ketosis, dystocia, twinning, lameness, and other non-specific illnesses can have an impact on reproductive efficiency.
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Meadows, Cheyney. "Evaluation of the effects of a contract breeding program on reproductive efficiency in Ohio dairy herds." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1117163496.
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Adamec, Vaclav. "The Effect of Maternal and Fetal Inbreeding on Dystocia, Calf Survival, Days to First Service and Non-Return Performance in U.S. Dairy Cattle." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/25999.
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Intensive selection for increased milk production over many generations has led to growing genetic similarity and increased relationships in dairy population. In the current study, inbreeding depression was estimated for number of days to first service, summit milk, conception by 70 days non-return, and calving rate with a linear mixed model (LMM) approach and for calving difficulty, calf mortality with a Bayesian threshold model (BTM) for categorical traits. Effectiveness of classical and unknown parentage group procedures to estimate inbreeding coefficients was evaluated depending on completeness of a 5-generation pedigree. A novel method derived from the classical formula to estimate inbreeding was utilized to evaluate completeness of pedigrees. Two different estimates of maternal inbreeding were fitted in separate models as a linear covariate in combined LMM analyses (Holstein registered and grade cows and Jersey cows) or separate analyses (registered Holstein cows) by parity (1-4) with fetal inbreeding. Impact of inbreeding type, model, data structure, and treatment of herd-year-season (HYS) on magnitude and size of inbreeding depression were assessed. Grade Holstein datasets were sampled and analyzed by percentage of pedigree present (0-30%, 30-70% and 70-100%). BTM analyses (sire-mgs) were performed using Gibbs sampling for parities 1, 2 and 3 fitting maternal inbreeding only. In LMM analyses of grade data, the least pedigree and diagonal A matrix performed the worst. Significant inbreeding effects were obtained in most traits in cows of parity 1. Fetal inbreeding depression was mostly lower than that from maternal inbreeding. Inbreeding depression in binary traits was the most difficult to evaluate. Analyses with non-additive effects included in LMM, for data by inbreeding level and by age group should be preferred to estimate inbreeding depression. In BTM inbreeding effects were strongly related to dam parity and calf sex. Largest effects were obtained from parity 1 cows giving birth to male calves (0.417% and 0.252% for dystocia and calf mortality) and then births to female calves (0.300% and 0.203% for dystocia and calf mortality). Female calves from mature cows were the least affected (0.131% and 0.005% for dystocia and calf mortality). Data structure was found to be a very important factor to attainment of convergence in distribution.Ph. D.
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Toscano, Laura Carvalho Pereira. "Perdas de gestação em vacas leiteiras." Master's thesis, Universidade de Lisboa. Faculdade de Medicina Veterinária, 2016. http://hdl.handle.net/10400.5/11367.
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Dissertação de Mestrado Integrado em Medicina VeterináriaA reprodução impulsiona o ciclo produtivo dos bovinos de aptidão leiteira e cárnica e representa um grande peso económico nas explorações. Depois dos custos relacionados com a nutrição, a fertilidade é o fator com maior impacto na economia da exploração leiteira, representando as perdas de gestação uma das causas de decréscimo da fertilidade na exploração. Neste trabalho pretende-se estudar a mortalidade embrio-fetal e aborto em vacas leiteiras, em três explorações no Alentejo, tal como as suas causas e consequências. A recolha de dados foi realizada durante 6 meses (de Agosto de 2014 a Janeiro de 2015) em 3 explorações de bovinos leiteiros situadas nos distritos de Portalegre (uma) e Évora (duas), em Portugal. Todas as explorações apresentaram valores de mortalidade embrio-fetal dentro do esperado (2,70%, 4,08% e 4,57%), entre os 30 e os 60 dias após a inseminação. É importante analisar possíveis causas de natureza infeciosa que poderão estar por trás deste achado, através das ferramentas ao dispor do médico-veterinário. Estando no Alentejo, e no que diz respeito ao stress hipertérmico durante o Verão, que tanto prejudica a fertilidade de bovinos de aptidão leiteira, é também importante elucidar o produtor sobre o maneio alimentar e hormonal dos animais sujeitos a condições de calor.
ABSTRACT - Pregnancy losses in dairy cows - Reproduction boosts the productive cycle of dairy and beef cattle and is a major source of income for the farms. After costs related to nutrition, low fertility can impact the farm economy with abortions representing the main factor of decreased fertility in the farm. This work aims to study the causes and consequences of embryo-fetal mortality and abortion in dairy cattle at three farms in Alentejo, Portugal. Data collection was carried out in the districts of Portalegre (one of the farms) and Évora (the other two farms) for a period of 6 months, between August 2014 and January 2015. All farms showed embryo-fetal mortality values within the expected range (2.70%, 4.08% and 4.57%), between 30 and 60 days after insemination. It is important to analyze possible causes of decreased fertility including the impact of infectious diseases that may be behind this result, using the available tools for the veterinary practioner. Being in Alentejo, and regarding thermal stress during the summer, which also affects the fertility of dairy cattle, it is equally important that farmers are duly educated on the diet and hormonal management of animals dealing with high environmental temperatures.
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Nqeno, Noluvuyo. "Reproductive performance of cows in sweet and sour veld types under communal production systems in the Eastern Cape Province of South Africa." Thesis, University of Fort Hare, 2008. http://hdl.handle.net/10353/141.
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The objective of the study was to evaluate cow reproductive performance in the sweetveld and sourveld communal grazing areas of the Eastern Cape Province, South Africa. In the first experiment, farmer perceptions were obtained using participatory rural appraisals. Farmers ranked lack of fences, tick-borne diseases, poor animal condition during winter and poor breeding practices, respectively as major constraints limiting cattle production in the Eastern Cape. Cattle, sheep and goats, in that order, were ranked as the most important livestock species and were mainly kept for meat, cash and ceremonies, respectively. The non-descript cattle breed was the most common breed found in the smallholder areas. Most farmers preferred Nguni breed because of its adaptive attributes. In the second experiment, structured questionnaires were administered, between June and August 2006, to a total of 551 farmers from 10 communities of the Eastern Cape. There was a significant association (P<0.05) between the use of pregnancy diagnoses and community. About 87 and 77 % of the interviewed farmers did not respond on the extent of pregnancy and calving rates in their herds. A higher proportion of farmers from Hekele (51%) and from Upper Mnxe (45.3%) communities reported low number of bulls as a major constraint to cow reproductive performance. Body condition and ovarian activity were measured in the sweet and sour veld types. Body condition score of animals was measured from March iii 2007 until January 2008 and ovarian activity of cows was performed by a veterinarian through rectal palpation in June, August and October 2007 and January 2008. From March to July, there was a marked decline in body condition on both veld types. In the sweetveld, body condition improved from September until January, whereas in the sourveld the improvement in body condition started in October. The cows in both veld types conceived throughout the year. Most cows in the sweetveld were cycling in January and August (P<0.05) whereas in the sourveld there was no distinct period when the animals were cycling. Overall, there were no differences in the proportion of cows that were cycling between the sour and sweet veldts (P>0.05). There were more cows cycling in sourveld in October than in the sweetveld. Reproductive performance of cows in communal areas could, therefore, be determined by levels and quality of nutrition. Keywords: Participatory rural appraisals; Structured questionnaires; Farmer participation; Farmer perceptions; Body condition scoring; Ovarian activity; Pregnancy diagnoses.
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Tortosa, Christina Suzanne. "Reproductive diseases of dairy cattle /." Click here to view, 2009. http://digitalcommons.calpoly.edu/dscisp/6.
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Thesis (B.S.)--California Polytechnic State University, 2009.Project advisor: Edwin Jaster. Title from PDF title page; viewed on Jan. 21, 2010. Includes bibliographical references. Also available on microfiche.
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Morton, John. "Determinants of reproductive performance of dairy cows in commercial herds in Australia /." Connect to thesis, 2004. http://eprints.unimelb.edu.au/archive/00000608.
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Fatehi, Jalal. "Genetic aspects of advanced reproductive biotechnologies in dairy cattle." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0022/MQ51061.pdf.
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Schmoeller, Ruminiki Pavei. "Implementação em software de um modelo de avaliação da eficiência reprodutiva de rebanhos leiteiros como instrumento para a tomada de decisão." Universidade Tecnológica Federal do Paraná, 2016. http://repositorio.utfpr.edu.br/jspui/handle/1/2198.
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Este trabalho faz um estudo em propriedades leiteiras no oeste do Paraná com objetivo de (1) formar um entendimento sobre as características sociais, econômicas, gerencias e tecnológicas presentes nas propriedades; (2) implementar em software um modelo de avaliação da eficiência reprodutiva de rebanhos leiteiros e (3) avaliar a aceitação dos produtores ao uso do software. Para isso foi realizada pesquisa quantitativa descritiva com 100 produtores de Medianeira, São Miguel do Iguaçu e Serranópolis do Iguaçu, no oeste do estado, buscando, com base na análise estatística, identificar, entre outros, os padrões para a prática da escrituração zootécnica e uso da tecnologia da informação. Os resultados mostraram que 90% dos produtores mantém algum nível de controle zootécnico, no entanto 72% não avaliam qualquer indicador de desempenho. Entre os produtores que mantém algum controle zootécnico, 87% o fazem em papel. Em média, 74% dos produtores desconhece a margem de lucro da atividade. Tanto no controle de custos, quanto no controle zootécnico e uso de sistemas de informação, não foram identificadas diferenças significativas no comportamento de produtores mais jovens. O software desenvolvido foi utilizado durante dez meses em uma propriedade leiteira com 150 animais da raça holandesa, sendo atualizado semanalmente com os eventos reprodutivos do rebanho. Com o uso do modelo pôde-se analisar 68% dos animais do rebanho (100% dos animais em estágio reprodutivo), uma abrangência quatro vezes maior do que a obtida por meio da fórmula de cálculo do intervalo entre partos (IEP). Foram realizados treinamentos com dois grupos de produtores de diferentes faixas etárias para avaliação da aceitação do software com ênfase nos construtos de expectativa de desempenho, expectativa de esforço, atitude para o uso, condições facilitadoras, autoeficácia e ansiedade frente ao uso do sistema. Em relação a aceitação do software, a expectativa de desempenho (utilidade) foi o aspecto mais bem avaliado pelos produtores. A autoeficácia foi o aspecto de menor percepção, demonstrando maior preocupação dos produtores com possíveis dificuldades que poderiam enfrentar durante o uso.This work does a study on dairy farms in western Parana in order to (1) form an understanding of the social, economic, managerial and technological characteristics present in the property; (2) implement in software an evaluation model of reproductive efficiency of dairy herds and (3) evaluate the acceptance of the producers to the use of software. For it was carried out a descriptive quantitative research with 100 producers of Medianeira, São Miguel do Iguaçu and Serranópolis do Iguaçu, in the western state, seeking, based on statistical analysis, identify, among others, the practice of zoo technical bookkeeping and use of information technology.. The results showed that 90% of manufacturers stated maintain some level of control livestock, however 72% do not evaluate any performance indicator. Among the producers who keeps some livestock control, 87% they do it on paper. On average, 74% of farmers unaware of the profit margin of the activity. Both in cost control, as the livestock control and use of information systems, no significant differences were identified in the behavior of younger producers. The software developed was used for ten months in a dairy property with 150 Holstein animals race, being updated weekly with the reproductive herd events. With the use of the model can analyze 68% of herd animals (100% of the animals at reproductive stage) an extent four times greater than the range obtained by calculation formula calving interval. Training was conducted with two groups of producers of different age groups to evaluate the acceptance of the software with an emphasis on performance expectation constructs, of performance, effort expectancy, attitude for the use, facilitating conditions, self-efficacy and anxiety during use of the system. Regarding the software acceptance, the performance expectations (utility) was the aspect best rated by the producers. The self-efficacy was the appearance of lower perception, showing greater concern for producers with possible difficulties that could face during the use.
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Fitzgerald, Tracey. "The effect of long-term supplementation with biotin on lameness, milk production and reproductive performance in pasture fed dairy cows /." [St Lucia, Qld.], 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16283.pdf.
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Mekonnin, Alemselam Birhanu. "Monitoring and improving reproductive performance of crossbred dairy cattle in Tigray Region, Ethiopia." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28876.
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Ethiopia maintains an extensive livestock population; however, reproductive performance of cattle and their breeding management are unsatisfactory. Currently, the sole diagnostic tool in the country is rectal palpation, which is inaccurate for early pregnancy in cattle. The study assessed reproductive performance and major reproductive problems using questionnaire survey, and evaluated simple, cost-effective alternative monitoring approaches using on-farm diagnostic tools to determine milk and serum progesterone (P4) and evaluate reproductive status. There were 177 dairy farms (range 1-115 cattle per farm) included in the questionnaire survey. Of these, 47 participated in the quantitative determination of P4 and estradiol profiles that used an enzyme-linked immunosorbent assay (ELISA) and in the on-farm diagnostic trial that used qualitative ELISA (Target P4 and Dipstick (P4 Rapid), and the reproductive status of 319 crossbred [Holstein Friesian (HF) X Zebu] dairy cattle was assessed. Questionnaires indicated that heifers in the study area reach puberty at older age and calve late, and cows have long postpartum estrus and calving interval. Anestrus, repeat-breeding, dystocia, retained fetal membranes (RFM), endometritis and abortion as the major reproductive problems in dairy cattle in the study area. Serum, milk, saliva and urine P4 and serum estradiol profiles of cattle at different reproductive status was determined using quantitative laboratory ELISA. High P4 levels was detected in pregnant and diestrus cattle than cattle that were anestrus and in-heat. Estradiol level was higher in cattle that were in-heat than cattle in other reproductive conditions. On-farm P4 ELISA indicated in-heat (estrus) 10 (3.1%), anestrus 77 (24.2%), repeater (follicular cyst) 9 (2.8%), normally cycling 69 (21.6%) and pregnant 154 (48.3%). The field P4 ELISA findings were validated using quantitative laboratory P4 ELISA, and similar results were obtained. The sensitivity and specificity of on-farm and laboratory P4 ELISA tests for diagnosing pregnancy were 88.6 & 99.4% and 98.1 & 100%, respectively. Once reproductive problems were identified using on-farm P4 ELISA and per rectal palpation, along with reproductive history, 122 cattle (75 cows and 47 heifers) were assigned to a 10-day Controlled Internal Drug Release (CIDR) in combination with prostaglandin F2-alpha (PGF2α) and equine chorionic gonadotrophin (eCG) based estrus synchronisation protocol to study the estrus response and conception rate. The overall estrus response and conception rates were 97.5% and 78.3%, respectively, with no significant differences in parity, pre-treatment reproductive status (anestrus or cycling (repeat-breeding/silent-estrus)) and farming system (smallholder vs organised commercial farms). The study has shown high estrus response and conception rate. Hence, this protocol is highly recommended to enhance fertility of dairy cattle in the study area and other regions. Finally, the study has determined the macronutrient composition of milk and assessed the effect of reproductive status, farm (nutritional) management, stages of lactation, parity and breed on milk composition in 246 dairy cows. This consisted of 184 crossbred cows from smallholder (n= 76: 36 non-pregnant and 40 pregnant) and organised commercial dairy farms (n= 108: 62 non-pregnant and 46 pregnant) in and around Mekelle, Ethiopia and by way of comparison, 62 HF cows (25 non-pregnant and 37 pregnant), either managed indoors or outdoors in a commercial farm in Edinburgh, United Kingdom. The mean milk fat, protein, lactose, total solid (TS) and solid-no-fat (SNF) recorded were 2.36%, 3.46%, 4.37%, 10.39% and 7.82%, in crossbred dairy cows, compared with 5.05%, 3.71%, 4.72%, 13.68% and 8.43%, in HF cows, respectively. Significantly lower (p < 0.05) level of macronutrient was recorded in milk from crossbred cows than HF cows. Milk fat in both breeds was affected by reproductive status, farm (nutritional) management and stages of lactation, but not by parity. In both cattle breeds, the milk fat content was significantly higher (p < 0.05) in pregnant than non-pregnant cows. Milk protein content was significantly (p < 0.05) affected by reproductive status (in crossbreds) and stages of lactation (in both breeds), but not by farm management or parity. Reproductive status (in crossbreds), stages of lactation (in both breeds) and parity (in crossbreds) affected lactose level; however, farm management had no effect on lactose level in both breeds. Milk fat was the most affected macronutrient content in both breeds. Low milk fat level in crossbred cows could be as a result of samples obtained from early milking coupled with nutritional management. In conclusion, the present study has determined the major reproductive problems in crossbred dairy cattle, assessed their actual reproductive status using rapid, cost effective, simple and applicable on-farm P4 tests, and established P4 and estradiol profiles at different reproductive status. The major breeding problem was poor estrus detection evidenced when animals reported anestrus were confirmed normally cycling using on-farm as well as laboratory P4 assays. These studies offer opportunities for establishing simple field reporting of reproductive status in these crossbred dairy cattle, which can have a major impact on breeding management and productivity.
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Rutley, Bruce David. "Genetic and environmental factors affecting early lactation milk progesterone measures of reproductive function." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64486.
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Bérodier, Marie. "Utilisation en ferme des données de génotypage pour une gestion optimisée et durable de l'élevage laitier." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASA001.
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Depuis une dizaine d’années, de nouvelles méthodes d’estimation du niveau génétique des bovins sont proposées aux éleveurs de race Montbéliarde. Ces méthodes reposent sur le génotypage des individus, c’est-à-dire la lecture du génome en certains points-clés afin de connaitre une partie de ses caractéristiques. Ces informations peuvent être utilisées au cours de la vie de l’animal pour choisir le meilleur partenaire afin de produire une descendance conforme aux attentes de l’éleveur.Par une augmentation de la fiabilité et le large éventail des informations à disposition pour planifier et optimiser les accouplements à venir, le génotypage des femelles permet un plus grand progrès génétique, un plus faible apparentement des couples et un risque de concevoir un embryon atteint d’anomalie génétique diminué. La prise en compte des objectifs de sélection spécifiques du système d’élevage où évolue le troupeau permet d’améliorer encore ces résultatsOver the last 10 years, new methods have emerged for farmers to estimate the genetic level of their Montbéliarde cattle. These methods rely on the genotyping of animals, an approach to read and interpret key parts of their genome. This genomic information can be used during the entire life of the animal in order to find the best mate to produce offspring according to the farmer’s expectations.Female genotyping allows for a higher genetic gain, a smaller mate co-ancestry and a reduced risk to conceive an embryo affected by a genetic defect thanks to more complete and reliable information to be used to optimize the matings. Considering farming systems specific breeding objectives when planning the matings further improves these results
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Lagombra, Gregorio. "Analysis of the Reproductive Efficiency of the Dairy Herd at Western Kentucky University Farm." TopSCHOLAR®, 1985. https://digitalcommons.wku.edu/theses/2521.
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A study of the reproductive performance of 179 dairy cows during the period from December 1978 through March 1984 was conducted at the Western Kentucky University Farm, Bowling Green, Kentucky. The climatic data showed seasonal variation in temperature as follows: winter 3.10C, spring 15.7°C, summer 23.8°C, and fall 12.0°C. The seasonal humidity was similar for winter (81.2%), spring (83.4%), and fall (85.3%); but for summer it was considerably higher (89.4%).
The conception rate varied through all the months but was lowest during the summer months. Seasonal data for conception rate were obtained and the results were as follows: winter 54.1%, spring 46.4%, summer 15.6% and fall 39.0%. Low fertility during summer months was associated with high air temperatures and high relative humidities. The coefficient of correlation for temperature vs. conception was low (-0.15) because there was low fertility in some winter months and in some summer months. The coefficient of correlation for humidity vs. conception was high (-0.65), and the coefficient of determination was 42%. A completely randomized design and analysis were used, resulting in significant differences among seasonal fertility rates but no significant differences among months within seasons. Significant differences were found for the following comparisons: winter vs. spring, summer, and fall; spring vs. winter, summer, and fall; and summer vs. spring, fall, and winter. The total services involved were 546, and the total conceptions obtained were 155--resulting in a service per conception ratio of 3.52. The average number of days open was 177 (79 cows). The average number of days in the calving interval was 457 (63 cows).
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Peeler, Iris Dawn. "Synchronization and Resynchronization of Ovulation and Timed Insemination in Lactating Dairy Cows and Heifers." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/9880.
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This study was conducted to evaluate the efficacy of intravaginal progesterone (P4) inserts (CIDR) in synchronization protocols combined with timed artificial insemination (TAI) as related reproductive performance. In the first study, heifers were synchronized with CIDR inserts followed by TAI. Heifers in the estradiol cypionate (ECP) group were synchronized with a combination of ECP, CIDR, prostaglandin (PGF2α), and ECP (CIDR-ECP), while the gonadotropin-releasing hormone (GnRH) group was synchronized using a combination of ECP, CIDR, PGF2α, and GnRH (CIDR-GnRH). All heifers were bred at either 48, 56, or 72 hours (h) after CIDR removal. Overall pregnancy rate (PR) for synchronized heifers was 60.1%, and embryo survival rate (ESR) was 98%. Pregnancy rate for CIDR-ECP treated heifers was influenced by artificial insemination (AI) time. In conclusion, ECP or GnRH may be used effectively in a CIDR-based TAI program in heifers. In the second study, cows were synchronized with CIDR devices or Ovsynch. The CIDR group received a combination of ECP, CIDR, PGF2α, and GnRH, while the Ovsynch group was synchronized using a combination of GnRH and PGF2α. Cows were bred at either 0, 8, or 24 h after the final GnRH injection. Overall PR for first service was 30.5% with ESR of 82.8%. Overall resynchronization PR was 35.1% with an ESR of 84.8%. In conclusion, Ovsynch and CIDR-based protocols are equally effective in synchronizing ovulation in a TAI program and resulted in comparable PR.Master of Science
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Awasthi, Hitesh. "Excessive lipid contents in immature oocytes from repeat breeder dairy heifers /." Uppsala : Dept. of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/10463781.pdf.
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Båge, Renée. "On repeat breeding in dairy heifers : with special focus on follicular dynamics, ovulation, and oocyte quality /." Uppsala : Dept. of Obstetrics and Gynaecology, Swedish Univ. of Agricultural Sciences, 2002. http://epsilon.slu.se/v139.pdf.
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Hendricks, Katherine Elizabeth May. "Reproductive strategies in the postpartum dairy cow with reference to anovulation and postpartum uterine health." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0007013.
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Thesis (M.S.)--University of Florida, 2004.Typescript. Title from title page of source document. Document formatted into pages; contains 176 pages. Includes Vita. Includes bibliographical references.
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Alhojaily, Sameer M. "The Effect of Lactation and Energy Status on Gene Expression in the Main Reproductive Tissues of Lactating Dairy Cattle." DigitalCommons@USU, 2019. https://digitalcommons.usu.edu/etd/7588.
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Modern high-yielding dairy cows are currently producing far more milk than their ancestors due to a prolonged and intensive genetic selection for milk production trait accompanied by the revolutionary improvement in technology, management, and nutrition. On the other hand, a noticeable decline in fertility and reproductive performance was undeniably consistent with the increase in milk yield. This decline in fertility and reproductive performance are recognized worldwide and well documented in several studies. Dairy cows typically experience a period of energy deficit during the first few months of lactation due to the rapid increase in milk production and limited feed intake. This shortage of energy requirements results in loss of body fat which is associated with the disturbance of the normal levels of certain hormones and metabolites. The significant increase in milk yield has increased the severity and duration of the energy deficit which has an adverse effect on the main reproductive cells and tissues that profoundly contribute to fertility. These include the egg from the ovary, the early embryo, and the internal lining of the uterus. Fertilization of a healthy egg results in the development of an embryo with an excellent quality that can survive through the multiple stages of gestation, especially during the first two weeks of gestation when many embryos die. The embryos in the early stages are the most susceptible to the disturbance in their environment. Energy deficit was shown to negatively impact the egg and embryo quality and make the uterus lining suboptimal to support early embryo development. Understanding the mechanisms by which energy deficit influences the main reproductive tissues will help in developing profound strategies to improve fertility in dairy cows.
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Farmer, Bertrand. "The status of beta carotene and vitamin A in Quebec dairy herds and their effects on reproductive performance /." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63167.
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Lobago, Fikre. "Reproductive and lactation performnace of dairy cattle in the Oromia Central Highlands of Ethiopia : with special emphasis on pregnancy period /." Uppsala : Dept. of Clinical Sciences, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/2007121.pdf.
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Bode-Rhoads, Michelle Lynn. "Regulation of the growth hormone receptor, insulin-like growth factor (IGF) I and IGF binding protein 2 in reproductive tissues of dairy cattle during lactation and associated effects on fertility." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p3164490.
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Petersson, Karl-Johan. "Milk progesterone as a tool to improve fertility in dairy cows /." Uppsala : Dept. of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200746.pdf.
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Burchard, Javier F. "Effects of 60 Hz electric and magnetic fields on productivity, reproductive hormones, plasma minerals and minerals and neurotransmitter metabolites in cerebrospinal fluid in dairy cattle." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41992.
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This study was designed to determine the potential biological effects of electric and magnetic fields (EMF), generated by 735 kV alternating current (AC) high tension lines upon the hormonal profile, some health-related parameters, stress response and productivity in dairy cattle. An EMF exposure chamber to house eight animals at one time was constructed. Forty-nine cows were divided according to their production stage; 8 pregnant non-lactating cows, 16 pregnant lactating cows, 16 non-pregnant lactating cows and 9 non-lactating non-pregnant heifers. They were exposed to an EMF of 10 kilovolts per meter (kV/m) and 30 micro-Tesla $( mu T)$ in two different fashions: (a) for three consecutive periods of 28 days in two sequences either with the EMF on/off/on or off/on/off, in a switch back design; (b) for three consecutive periods with the sequence OFF (5 days), ON (30 days) and OFF (5-12 days). The intensity of the EMF chosen for the experiments resembled a situation in which the cattle are standing continuously under a 735 kV AC high tension line when the line has a maximum load of current. In reality, these conditions are found only for a few days during the winter in the Province of Quebec.Milk production and composition, feed consumption, blood hormonal profiles and cerebrospinal fluid (CSF) components were assessed during the different periods of exposure. Most of the variables assessed were not affected by EMF. However, there was a positive association between EMF and feed consumption, milk fat content, blood plasma progesterone during pregnancy and estrous cycle length. Also, there were changes in the mineral and neurotransmitter metabolite concentrations in the CSF that showed a relationship to the EMF.
In conclusion, it could be stated that EMF caused a biological response in dairy cattle. It is speculated that these changes do not represent a health hazard for exposed cattle, although they warrant further research.
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Pineiro, Juan M. Pineiro. "Associations of Pre- and Post-Partum Lying Time with Metabolic Status, Health, Survival, and Performance of Dairy Cows." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1524140004464786.
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Plöntzke, Julia [Verfasser]. "Prevalence of clinical and subclinical endometritis and their impact on reproductive performance in grazing dairy cattle in Buenos Aires Province, Argentina / Julia Plöntzke." Berlin : Freie Universität Berlin, 2011. http://d-nb.info/1029846146/34.
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Silvestre, Flávio Teixeira. "Reproductive, ovarian, and uterine responses to a GnRH-agonist (Deslorelin) implant during and after the postpartum summer heat-stress period in dairy cattle." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0002839.
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Burchard, Javier F. "Effects of 60 Hz electric and magnetic fields on productivity, reproductive hormones, plasma minerals and minerals and neurotransmitter metabolites in cerebrospinal fluid in dairy cattle." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq29899.pdf.
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Ivanou, Aleh Vitorovich. "Clínica e reprodução de bovinos leiteiros." Master's thesis, Universidade de Évora, 2015. http://hdl.handle.net/10174/17493.
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O presente relatório resulta do estágio curricular realizado na área de Clínica de Espécies Pecuárias, no âmbito do Mestrado Integrado em Medicina Veterinária. Na primeira parte, são descritas as explorações onde o estágio se realizou e as atividades desenvolvidas nas mesmas. Numa segunda parte, efetuou-se uma revisão bibliográfica sobre os fatores reprodutivos que afetam explorações leiteiras e, numa terceira parte, desenvolve-se análise dos índices reprodutivos nas explorações onde decorreu o estágio. No presente trabalho pretendeu-se descrever os principais fatores que influenciam os parâmetros reprodutivos de uma exploração de bovinos de leite, de modo a perceber a ação destes em regime intensivo, comparando duas formas de assistência veterinária, permanente e periódica. Os dados foram tratados graficamente para avaliar os principais índices reprodutivos. O estudo revelou que as altas produções leiteiras estão associadas a maiores problemas reprodutivos e que a assistência veterinária é um fator muito importante no desenvolvimento, implementação e controlo dos programas reprodutivos; Abstract:
Practice and Reproduction of dairy cattle.
The present report has been produced, as part of the master's degree in Veterinary Medicine. In the first part a description of the developed activities during the training post is presented. In the second part there is a review of the literature on the reproductive factors affecting the performance in dairy cattle. In the third part of the present work, an analysis of the reproductive performance on two hosting farms was produced. We described the main factors influencing the reproductive parameters of dairy production in order to understand their effects on both farms under evaluation, having in account the differences of veterinary services (internal and external). Our study showed that dairy production units with high production are associated with higher reproductive problems and, the veterinary activity on dairy health management is a very important factor on the development, implementation and monitoring of reproductive programs.
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Prata, Marco Aurélio. "Índices econômicos de seleção para rebanhos Gir Leiteiro." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/17/17135/tde-05012017-141219/.
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A produção de leite em geral é a característica mais importante em programa de melhoramento animal de rebanhos leiteiros. Vários estudos tem sido conduzidos para no Gir Leiteiro envolvendo a estimação de parâmetros genéticos para características produtivas nos últimos anos, mas pequena atenção foi dada a saúde do úbere e características reprodutivas. Os índices de seleção são utilizados em vários países para selecionar animais mais lucrativos e para quantificar a resposta correlacionada entre as características a serem incluídas como objetivos de seleção. Este trabalho tem como objetivo desenvolver um estudo visando a construção de índices de seleção para posterior utilização na classificação e seleção dos animais avaliados no programa de teste de progênie de bovinos Gir Leiteiro no Brasil. Componentes de (co) variância para a produção de leite (PL), gordura (G), proteína (P), porcentagem de gordura (G%), porcentagem de proteína (P%), escore de células somáticas (ECS), intervalo de partos (IDP) e idade ao primeiro parto (IPP) foram estimados usando informações de desempenho fornecidas pela Associação Brasileira de Criadores de Gir Leiteiro (ABCGIL). Os dados incluíram registros de 10.146 vacas, filhas de 1005 touros, com partos ocorridos entre 1989 e 2013, distribuídas em 289 rebanhos. As análises estatísticas foram realizadas utilizando modelo animal, em análises bivariadas pelo método de máxima verossimilhança restrita (REML). Sete diferentes índices foram propostos (chamados GPI = Gir Performance Index), com alternativos objetivos de seleção e fatores de ponderação. GPI-1: PL + G +P, incluindo os respectivos valores econômicos (VE$) das características. GPI-2: PL + P + IDP + IPP, incluindo os respectivos valores econômicos (VE$) para as características reprodutivas e ponderação zero para IDP e IPP; GPI-3: PL + P + IDP + IPP, incluindo os respectivos valores econômicos (VE$) para as características produtivas e para IDP, e ponderação zero para IPP. Baseados nas possíveis respostas esperadas obtidas nos índices anteriores, diferentes fatores de ponderação foram atribuídos para as características do GPI-4 ao GPI-7. GPI-4: 0.20*PL + 0.40*P - 0.30*IPP - 0.10*IDP; GPI-5: 0.10*PL + 0.50*P - 0.10*IPP - 0.30*IDP; GPI-6: 0.10*PL + 0.60*P - 0.10*IPP - 0.20*IDP e GPI-7: 0.10*PL + 0.30*P - 0.20*IPP - 0.40*IDP. O GPI-1, GPI-2, GPI-3 e GPI-4 apresentaram maiores respostas para a produção de leite. Pequenas diferenças nas respostas para P foram observadas entre os índices. A resposta para IDP diminuiu do GPI-1 ao GPI-7 o que pode ser favorável, pois diminuiria o IDP. Entretanto, não foram obsevadas grandes diferenças entre as respostas econômicas, indicando que é possível a seleção para características reprodutivas sem diminuir o lucro. Os resultados sugerem que a seleção somente para produção de leite poderia levar a um declínio no desempenho reprodutivo. A inclusão da PL, P, IDP e IPP como objetivos de seleção no programa desenvolvido pela ABCGIL poderia promover um equilíbrio entre o melhoramento das características produtivas e reprodutivas. No entanto, espera-se lenta resposta à seleção devido às baixas estimativas de herdabilidade das características.Milk production traits in general are the most important trait in dairy cattle breeding program. Several studies have been conducted on Gir cattle involving the estimation of genetic parameters for milk production traits over last years, but small attention was given to udder health and reproductive traits. Selection indexes have been used around the world to select more profitable animals and to quantify the correlated response among all traits included in the breeding goal. Thus, the main goal of the present study was to develop a selection indexes for future use in the classification and selection of animals evaluated in a breeding program of Gir dairy cattle in Brazil. The estimate genetic parameters for 305d milk yield (MILK); fat yield (F), fat content (F%), protein yield (P), protein content (P%), lactation somatic cell score (LSCS), calving interval (CI) and age at first calving (AFC), were calculated using information on milk and reproduction traits provided by the Brazilian Association of Gir Dairy Breeders (ABCGIL). Dataset included records of 10,146 cows, daughters of 1,005 sires, who calved between 1989 and 2013, reared in 289 herds. The statistical analyses were carried out by an animal model, in bivariate analyses using the restricted maximum likelihood method. Seven different situations were created in the present study to define the breeding goals for Gir Dairy cattle (named GPI = Gir Performance Index). GPI-1; MILK + F + P, including the respective economic values (EV$) of traits; GPI-2: Milk + P + AFC + CI, including the respective economic values (EV$) for milk traits and zero for CI and AFC; GPI-3: M + P + AFC + CI, considering EV ($) for MILK, P, CI and zero for AFC. Based on possible expected responses obtained from previous indexes, different weighting factors were attributed to traits in GPI-4 to GPI-7. GPI-4: 0.20*MILK + 0.40*P - 0.30*AFC - 0.10*CI; GPI-5: 0.10*MILK + 0.50*P - 0.10*AFC - 0.30*CI; GPI-6: 0.10*MILK + 0.60*P - 0.10*AFC - 0.20*CI and GPI-7: 0.10*MILK + 0.30*P - 0.20*AFC - 0.40*CI. GPI-1, GPI-2, GPI-3 and GPI-4 provided higher genetic responses for MILK. Small differences on responses were observed for P across all indexes. Responses for CI decreased from GPI-1 to GPI-7, which could be favorable, however no differences among the economic selection response were observed, indicating that is possible include reproduction traits in the index without decrease the profit. These results suggest that the selection based only on the improvement of milk yield could lead to a decrease in reproduction performance. These results suggest that inclusion of MILK, P, CI and AFC traits in the breeding goals in the breeding program developed by ABCGIL could generate a balanced improvement of production and reproduction traits. However, is expected smal response to selection due to low heritability estimates for these traits.
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Fraga, Cecília Archer de Menezes Castro. "Medicina da produção leiteira : estudos de relação entre o desempenho reprodutivo e as mastites." Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2018. http://hdl.handle.net/10400.5/15046.
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Dissertação de Mestrado Integrado em Medicina VeterináriaO impacto das mastites na eficiência reprodutiva dos bovinos leiteiros, tem sido estudado ao longo dos últimos anos, por diversos autores. O objetivo do presente estudo, foi analisar a possível associação causal entre a ocorrência de mastites subclínicas e a alteração do desempenho reprodutivo. Recorrendo a uma base de dados de contraste leiteiro, na qual existiam registos provenientes de 9 explorações nacionais, introduzidos entre 1996 e 2016, procedeu-se à análise da relação da contagem de células somáticas, com o intervalo parto-conceção. Os resultados obtidos demonstraram que, à medida que aumenta a contagem de células somáticas, aumenta o intervalo parto-conceção. Tais resultados foram estatisticamente significativos e mais pronunciados para os dados relativos à segunda lactação. Observou-se ainda que, para cada aumento do número de eventos, cuja contagem de células somáticas se encontra acima do limiar de distinção entre infetado e saudável, o intervalo parto-conceção aumenta 28,7 dias para a primeira lactação e 27,9 dias para a segunda. Tais resultados, sugerem a hipótese de haver uma relação da cronicidade da infeção, com a fertilidade. Assim, à semelhança do reportado por autores anteriores, os resultados obtidos apontam a existência de uma relação entre as mastites subclínicas e o desempenho reprodutivo dos bovinos leiteiros.
ABSTRACT - Dairy Production Medicine: studies of the relationship between reproductive performance and mastitis - The impact of mastitis on reproductive performance of dairy cattle has been studied throughout the last years, by several authors. The objective of this study was to evaluate the possible causal association between the occurrence of subclinical mastitis and altered reproductive performance. Through the analysis of a database, in which there was access to milk recording data from 9 national dairy farms, introduced from 1996 to 2016, the relationship between the somatic cell count and the calving-to-conception interval was analyzed. The obtained results showed that, as the somatic cell count increases, the calving-to-conception interval increases. These results were statistically significant and more pronounced on the second lactation. Furthermore, it was observed that, with increases in the number of mastitis episodes, in which somatic cell counts were above the considered threshold between infected and healthy, the calving-to-conception interval progressively increased 28,7 days for the first lactation and 27,9 days for the second. These results support the existence of a relationship between the chronicity of the episodes and fertility. As such, similarly to results presented by previous authors, this study supports the existence of a direct relationship between mastitis and the reproductive performance of dairy cattle.
N/A
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Pereira, Mikaele Alexandre. "Utilização de funções matemáticas em sistemas de produção de leite na região de Nossa Senhora da Glória, Estado de Sergipe." Pós-Graduação em Zootecnia, 2013. https://ri.ufs.br/handle/riufs/6405.
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The objective of this study outline a diagnosis of dairy farming in the municipality of Nossa Senhora da Gloria, State of Sergipe, addressing productive and reproductive aspects, and test mathematical models for their suitability to describe the curves of growth and lactation in cattle compounds by crossbred animals Taureans x Zebu cattle. Article 1: Technical evaluation of milk production systems in the region of Nossa Senhora da Gloria, State of Sergipe. Eight producers were selected, which were grouped according to the following scale daily milk yield (kg/day) Group 1 (G1) . 100 kg/day, group 2 (G2): > 100 kg / day . 500, Group 3 (G3):> 500 kg / day. Productivity per cow per year differed between groups (p <0.05) with values of 2.226,06, 4.428,50 and 6063.84 kg / cow / year for G1, G2 and G3, respectively. In land productivity G1 (1.801,63 kg / ha / year) did not differ from G2 (1.562,26 kg/ha/year) and G3 (3.798,08 kg/ha/ year), however the latter two differed other (p <0,05). The reproductive indices obtained for G1, G2 and G3 were: calving interval of 14,59, 12,96 and 13,14 months; service period 169,89, 121,89 and 125,95 days and rates of pregnant 14,87, 28,01 and 17,99%. The G2 got better reproductive rates (P <0,05). Given the above, it is concluded that the groups of producers with production less than 100 kg of milk/day and between 101 and 500 kg milk/day are technically feasible for the region studied. Article 2: Comparison of nonlinear models to describe the growth of females Taurino x Zebu crossbred dairy cattle in Nossa Senhora da Gloria, State of Sergipe. We used 537 records of weighings made at intervals of 30 days during the period from 2010 to 2012. The mathematical models used were: Brody (BD), Von Bertalanffy (VB), Logistics (LG) and Gompertz (GP). The weights and asymptotic growth rates instant (TCI) were respectively: BD, 1.982 kg and 0,451 to 0,555 kg/month, for VB, 550,50 kg and 0,535 to 12,04 kg/month, LG, 405,20 kg and 0,0021 to 0,180 kg/month, GP, 479,70 kg and 0,259 to 0,623 kg/month. The VB model fitted well the growth curve, however showed greater deviation in the rate curve TCI compared to the observed data. The GP model showed better adaptation to growth data crossbred females with genetic variation between groups of Taurino x Zebu crosses in semi-extensive system. Article 3: Shape of lactation curve in Taurino x Zebu crossbred females in the semi-arid region of Sergipe. 1496 records were used for milk production performed every 30 days during the period from 2011 to 2012. The adjustment was made for the mean curve, making the use of four mathematical models: Nelder, 1966 (ND), Wood, 1967 (WD), Bianchini Sobrinho, 1984 (BS) and Wilmink, 1987 (WK). The average values of Ra2 were <0,82. All curves showed typical patterns. The other functions in the graph showed similar distribution of waste, however only the function ND was able to estimate the components of the lactation curve effectively.Objetivou-se com esse estudo tracar um diagnostico da atividade leiteira no municipio de Nossa Senhora da Gloria, Estado de Sergipe, abordando aspectos produtivos e reprodutivos, e testar modelos matematicos quanto a sua adequacao para descrever as curvas de crescimento e de lactacao de rebanhos compostos por animais mesticos de Taurinos x Zebus. Artigo 1: Avaliacao tecnica de sistemas de producao de leite na regiao de Nossa Senhora da Gloria, Estado de Sergipe. Foram selecionados oito produtores, os quais foram agrupados de acordo com a seguinte escala de producao de leite diaria (kg/dia): Grupo 1 (G1): . 100 kg/dia; Grupo 2 (G2): > 100 kg/dia e . 500; Grupo 3 (G3): > 500 kg/dia. A produtividade por vaca por ano diferiu entre os grupos (p<0,05) com valores de 2.226,06, 4.428,50 e 6.063,84 kg de leite/vaca/ano para G1, G2 e G3, respectivamente. Na produtividade da terra o G1 (1.801,63 kg/ha/ano) nao diferiu de G2 (1.562,26 kg/ha/ano) e G3(3.798,08 kg/ha/ano), no entanto estes dois ultimos diferiram entre si (p<0,05). Os indices reprodutivos obtidos para G1, G2 e G3 foram respectivamente: intervalo de partos de 14,59, 12,96 e 13,14 meses; periodo servico de 169,89, 121,89 e 125,95 dias e taxas de prenhes de 14,87, 28,01 e 17,99%. O G2 obteve melhores indices reprodutivos (P<0,05). Diante do exposto, conclui-se que os grupos de produtores com producoes menores que 100 kg de leite/dia e entre 101 e 500 kg de leite/dia sao tecnicamente viaveis para a regiao estudada. Artigo 2: Comparacao de modelos nao-lineares para descrever o crescimento de femeas mesticas Taurino x Zebu na bacia leiteira de Nossa Senhora da Gloria, Estado de Sergipe. Foram utilizados 537 registros de pesagens realizadas em intervalos de 30 dias durante o periodo de 2010 a 2012. Os modelos matematicos utilizados foram: Brody (BD), Von Bertalanffy (VB), Logistico (LG) e Gompertz (GP). Os pesos assintoticos e as taxas de crescimento instantaneas (TCI) foram respectivamente: para BD, 1.982 kg e 0,451-0,555 kg/mes; para VB, 550,50 kg e 0,535-12,04 kg/mes; LG, 405,20 kg e 0,0021-0,180 kg/mes; GP, 479,70 kg e 0,259-0,623 kg/mes. O modelo VB ajustou-se bem a curva de crescimento, no entanto apresentou maior desvio na curva da taxa TCI em relacao aos dados observados. O modelo de GP apresentou melhor adaptacao aos dados de crescimento de femeas mesticas com variacao de grupos geneticos entre cruzamentos de Taurino x Zebu em sistema semi-extensivo. Artigo 3: Forma da curva de lactacao em femeas mesticas Taurino x Zebu no Semi-arido de Sergipe. Foram utilizados 1496 registros de producao de leite realizados em intervalos de 30 dias durante o periodo de 2011 a 2012. O ajuste foi feito para a curva media, fazendo-se o uso de quatro modelos matematicos: Nelder, 1966 (ND), Wood, 1967 (WD), Bianchini Sobrinho, 1984 (BS) e Wilmink, 1987 (WK). Os valores medios de Ra2 foram < 0,82. Todas as curvas apresentaram padroes tipicos. As demais funcoes apresentaram comportamento semelhante no grafico de distribuicao dos residuos, no entanto somente a funcao ND foi capaz de estimar os componentes da curva de lactacao de forma eficaz.
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Neves, Rafael. "Investigation of Automated Activity Monitoring Systems for Reproduction in Dairy Cattle." Thesis, 2011. http://hdl.handle.net/10214/2804.
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This thesis is an investigation of the reproductive performance of dairy herds managed using automated activity monitoring systems for heat detection (AHD) in comparison to herds using timed artificial insemination programs (TAI). Two approaches were taken: a randomized clinical trial and a retrospective cross-sectional study. In the field trial, pregnancy risk (PR) was not different between the AHD (14.6%) and TAI program (15.9%). Overall, time to pregnancy, time to 1st service and time to 2nd service were not different between breeding programs. In the observational study, annual herd-summary reproductive performance in farms using AHD and TAI were not different. Finally, a retrospective analysis in herds that were using AHD for more than one year compared the years before and after adoption of the system. A significant increase of PR and insemination risk was found. In conclusion, AHD systems had comparable reproductive performance to TAI-based programs.Ontario Ministry of Agriculture, Food and Rural Affairs. Gencor and SCR Engineers Ltd.
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Luna, Gonzalo. "Endocrine changes associated with the effect of nutrition on the timing of reconception and puberty in dairy cattle." Diss., 2000. http://hdl.handle.net/2263/22854.
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McKee, Sara Lynn. "Evaluation of oral colostrum or an organic botanical preparation on reproduction in dairy cattle." 2009. http://www.lib.ncsu.edu/theses/available/etd-11022009-160431/unrestricted/etd.pdf.
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Clark, Tina Marie. "The effects of the protein metabolites ammonia and urea on oocyte maturation, fertilization, and early embryo development, using an in vitro system." Thesis, 1996. http://hdl.handle.net/1957/34371.
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ŠPAČKOVÁ, Vladislava. "Vybrané vlivy na reprodukci plemenic holštýnského skotu." Master's thesis, 2019. http://www.nusl.cz/ntk/nusl-396068.
Full textAbstract:
The work deals with the evaluation of selected effects on reproduction of Holstein cattle breeds. The aim of the study was to evaluate reproductive parameters (insemination index, insemination interval, period service, interim, pregnancy after the first insemination) in a selected group of dairy cows. These reproductive indicators were subsequently evaluated depending on genotype, performance level, lactation order and age at first calving and used synchronization methods. The evaluation took place at the Vřesce farm, belonging to company Rynagro a.s. 260 Holstein breed cows and their hybrids were included. The results showed that some reproductive indicators (insemination interval, service period and interim) of the monitored group of dairy cows were lower than the average of the Czech Republic. When evaluating the genotype effect on reproductive parameters, a highly significant effect (p<0.01) of genotype on insemination interval was found. Holstein breed cows had a 7-day higher insemination interval than other crosses. In evaluating the effect of daily milk yield was not proven statistically significant differences (p>0.05) in period servis and interim. Statistically significant differences (p<0.05) in insemination index, insemination interval and pregnancy after the first insemination were proven in the performance evaluation. The p-value of the global null hypothesis was close to 0.05 and no significant differences between the compared groups were demonstrated in the subsequent multiple comparison. The effect of the order of lactation on reproductive parameters was not proven (p>0.05). However, interesting results were found by the impact of age at first calving. There was a statistically highly significant difference (p<0.01) between the groups in the insemination interval and the interim and a statistically significant difference (p<0.05) between the groups in the service period. Cows with a first calving age 23 months had all of these indicators lowest, the highest values were found within cows with a first calving age of 28 months. After evaluating the correlation analysis, a significant effect of age at first calving on insemination interval (p<0.05; r=0.13), on interim (p<0.01; r=0.17) and period service (p<0.01; r=0.17). Synchronization methods were used in 125 cows and the overall success rate after this treatment was 47%. The most commonly used protocol was the Ovsynch method. The calculations based on the extension of the service period quantified the theoretical loss for the extended cycle of dairy cows. This loss is 7 030, - CZK per cow and takes into account the losses for milk and the unborn calf, not the cost of further insemination and treatment of cows.
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Todd, Caryn Jayne. "Investigation of leptin genotypes and economically important dairy traits in jersey cows." Thesis, 2005. http://hdl.handle.net/10413/5490.
Full textAbstract:
Dairy farming is one of the most important agricultural industries in South
Africa, and thus improving the performance of dairy cows, with respect to
economically important dairy traits, would be beneficial. Selection of dairy
cows has traditionally been phenotypic, but new molecular techniques have
made it possible to evaluate phenotypic dairy traits at the DNA level, providing
the possibility of more accurate selection. The economically important dairy
traits, milk production and reproductive performance, are quantitative traits,
and are therefore controlled by many genes and the environment. A number
of genes have been identified that have been shown to influence economically
important dairy traits, including the lep gene. This gene encodes the hormone
leptin, which has been proven to regulate feed intake, energy balance, fertility
and immune function. A polymorphism has been identified in the lep gene,
which may be associated with economically important dairy traits. This study
on a South African Jersey herd investigated the possible association of the
polymorphism, RFLP-Kpn 21, with milk production and reproductive
performance. The lactation records of fifty Jersey cows that completed their
first lactation between 1997 and 2004 were collected, and these cows were
genotyped for the RFLP-Kpn 21 polymorphism, located at exon 2 of the lep
gene. This involved the extraction of DNA from venous blood, using a salting
out technique. The extracted DNA was amplified using PCR primers; the
reverse primer included a purposeful mismatch. The role of the purposeful
mismatch was to create a recognition site for a restriction enzyme (Kpn 21),
thus allowing the alleles of the polymorphism to be identified through a
restriction digestion protocol. Two alleles were identified, the C- and the Tallele.
The genotype of each cow was identified using PAGE. The
significance of the genotype effects on the milk production traits and the
reproductive performance traits were estimated using the F-statistic provided
by a GLM Univariate analysis. In conclusion, no significant effect of the
RFLP-Kpn 21 polymorphism was found for milk yield, butterfat and protein
percentage, ICP and SPC (p > 0.05), but a possible association with lactose
percentage was suggested by the statistical analysis (p < 0.05). Further
investigation of South African Jersey cows will be necessary in order for
conclusive results to be obtained.Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.