Academic literature on the topic 'Calving interval'

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Journal articles on the topic "Calving interval"

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Newman, S., and MP Deland. "Lifetime productivity of crossbred cows. 2. Age and weight at first oestrus, calf birth weight, assisted calvings, calving interval and reproduction rate." Australian Journal of Experimental Agriculture 31, no. 3 (1991): 293. http://dx.doi.org/10.1071/ea9910293.

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Crossbred heifers were born in 1974 from 7 breeds of cattle by mating Hereford bulls to Shorthorn cows, Hereford bulls to Friesian cows (calves double-suckled), Hereford bulls to Jersey cows (and Jersey bulls to Hereford cows), and using semen or natural service of Sahiwal, Charolais, Simmental and Brahman bulls on Hereford cows. Breed differences were important sources of variability for age and weight at first oestrus. The heifers were joined with Hereford bulls to produce backcross progeny during the years 1976-84 in a semi-arid environment. Parity (confounded with year and age of dam) and its interaction with breed had significant effects on frequency of assisted calvings, birth weight, calving rate and weaning rate. On average, over all parities, European cross dams (Charolais, Simmental) had calves of higher birth weight than other types but also had more assisted calvings, a lower calving rate and longer calving interval. Dairy cross dams (Friesian, Jersey) had early puberty, short calving intervals, few assisted calvings and higher calving rates. Zebu cross cows (Brahman, Sahiwal) had poor early reproductive performance due to late onset of oestrus, but similar or better subsequent calving rates and calving intervals. Their calves had lower birth weights but required similar assistance to Europeans. Shorthorn cross cows had similar calving intervals and more assisted calvings than other types in spite of their calves having average birth weights.
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Pilarczyk, R., and J. Wójcik. "Comparison of body weight and reproduction performance in cows of various beef breeds managed under equal conditions in West Pomerania." Archives Animal Breeding 51, no. 4 (October 10, 2008): 318–28. http://dx.doi.org/10.5194/aab-51-318-2008.

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Abstract. The aim of the study was to compare the body weight and the parameters of reproductive performance in beef cows of various breeds following their import to Poland from 1995–1997. The analyses included cows of five beef breeds: Red Angus, Salers, Hereford, Limousin and Simmental. We have compared the body weights and calving intervals during the period from their arrival to Poland in 1995 until 2002, with subsequent calvings included in the analyses. Other aspects included calving difficulty, abortions, stillbirths and twin births. The analysis of the cows’ reproductive performance has revealed that the studied breeds differ in the calving interval. Best results were achieved by Simmental and Limousine cows, while Red Angus cows exhibited the poorest performance. The effect of subsequent calving on the calving interval was also confirmed. We have observed no differences among the mature cows with respect to the body weight and calving ease.
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Garcia Paloma, J. A., R. Alberio, M. C. Miquel, M. O. Grondona, J. Carrillo, and G. Schiersmann. "Effect of calving date on lifetime productivity of cows in a winter-calving Aberdeen Angus herd." Animal Science 55, no. 2 (October 1992): 177–84. http://dx.doi.org/10.1017/s0003356100037430.

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AbstractLifetime productivity of 408 Aberdeen Angus cows from the Estacion Experimental Agropecuaria (EEA) of Balcarce, Argentina, was analysed during the 1972 to 1983 period according to their date of calving. Cows were allocated to two groups: one group of early first calving (Fl) when cows calved within the first 25 days of the calving period; the other, of late first calving (F2) when cows calved after that date. Independently using similar criteria, the effect of date of second calving on lifetime productivity was analysed in the same cows, groups SI and S2. Early first calving cows weaned more kg of calf when their first four calvings were considered than cows of late first calving (659 v. 628 kg). The same tendency was observed when cows were compared according to their second calving date (653 v. 634 kg). Differences in weaning weight between calves from early and late cows were only significant for the first calving (group Fl v. F2) and for first and second calving (group SI v. S2). This fact was a consequence of the shorter initial calving interval for late cows (F2 and S2) so that subsequent ages of their calves at weaning were similar to early cows (Fl and SI). Groups F2 and S2 cows had first and second calving intervals respectively of 351 and 356 days, while groups Fl and SI cows had intervals of 372 and 371 days. It is concluded that the date of the first calving and the high overall reproductive performance of the herd contributed to a high concentration of early calvings and a high productive efficiency.
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Tarrés, J., P. Puig, V. Ducrocq, and J. Piedrafita. "Factors influencing length of productive life and replacement rates in the Bruna dels Pirineus beef breed." Animal Science 78, no. 1 (February 2004): 13–22. http://dx.doi.org/10.1017/s1357729800053790.

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AbstractAn analysis of the length of productive life in the Bruna dels Pirineus beef breed was performed with a non-parametric approach giving an average value of 9 years of productive life, and a corresponding replacement rate of 11%. Using a proportional hazards model stratified by herd, the influence of calf birth weight and weight gain until weaning, calving difficulty, calving interval and age at first calving on length of productive life were studied. Two models were explored: the first one included time-dependent variables taking the current value of the covariate at each calving date, while the second one also comprised time-dependent interactions between the value of the covariate of the current calving and its mean value during the last (up to) three previous calvings. Results from the first model showed that the risk of culling increases with very high ages at first calving, increasing calving difficulties, very large calf birth weights, very small weight gains until weaning and very long calving intervals. Furthermore, results from the second model showed that these increases also depend upon a sequence of values for the same covariate in previous calvings. Finally, these higher risks of culling implied lower survival functions that increased replacement rates but only slightly decreased average performances.
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Oyedipe, E. O., D. I. K. Osori, A. G. Jagun, B. Ntunde, and L. O. Eduvie. "POST PARTUM UTERINE INVOLUTION AND RESUMPTION OF OVARIAN ACTIVITY IN WHITE FULANI (BUNAJI) AND FRIESIAN BUNAJI COWS AS DETERMINED BY RECTAL PALPATION." Nigerian Journal of Animal Production 7, no. 2 (January 14, 2021): 112–16. http://dx.doi.org/10.51791/njap.v7i2.2118.

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The rate of involution of the uterus and cervix, and resumption of ovarian activity were studied in Friesian x Bunaji and purebred Bunaji Zebu cattle. Determinations of the above parameters were made by rectal palpation of the genitalia, visual observations and by vasectomized bulls for signs of oestrus. Involution was found to be complete by 16 to 30 days for the crossbreeds and 17 to 27 days for the Bunaji. The mean interval from parturition to first oestrus was 18.5 ± 2.9 vs 21.4 ± 5.4 days for the Bunaji and Frieslam x Bunaji respectively. The interval between the first and second oestrus in the crossbred was significantly longer than in the purebred Buanji (P<.05). By 60 days postpartum, all the Bunaji had exhibited no less than 3 oestrous cycles as against the Friesian crosses with a mean of 2.4 cycles. Cystic ovaries (6.9%), pyometra (6.9%) and anoestrus (13.8%) observed among the crossbreds were not seen among the Bunaji cows examined. Calving records of the palpated cows were examined for their last three calvings under the range management practised on the farm. Three calving interval groups viz less than 322, 322 to 342 and above 342 days were recognized. In both breeds, most calvings were in the greater than 342 days interval, during which the 'Bunaji had longer calving interval (P< .01) in the pernultimate calving than the crosses.
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Brotherstone, Susan. "A note on the value and methods of correcting milk records for calving interval or days dry." Animal Science 44, no. 2 (April 1987): 322–25. http://dx.doi.org/10.1017/s0003356100018705.

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In formulating a genetic index for use in cow and sire evaluation, there is a need to account for all environmental factors which influence an animal's yield. To this end, milk production records are currently adjusted for, amongst other things, age at calving and month of calving. In Norway, Sweden and West Germany, records are corrected for calving interval, i.e. the number of days between subsequent calvings (Philipsson, Dommerholt, Fimland, Gaillard, Gjøl-Christensen, Lederer, McClintock and Mocquot, 1978), but in Britain no account is taken of calving interval or days dry. Analysis has shown (McClintock, 1982) that both these factors have a significant effect on yield, and hence further investigation into the value and methods of adjusting for these factors was required.
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Hossain, MS, MA Rahman, FY Bari, and MMU Bhuiyan. "Factors affecting calving to service interval in crossbred Friesian cows in a large dairy farm." Bangladesh Veterinarian 38, no. 1-2 (December 31, 2022): 33–41. http://dx.doi.org/10.3329/bvet.v38i1-2.63675.

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To determine the calving to service interval and its associated factors, 125 crossbred Friesian cows were studied. The farm records were randomly examined, and related data were collected on genotype, age, body weight, body condition score (BCS), parity, milk yield, suckling status and season of first postpartum service. The overall calving to service interval in Friesian crossbred cows was 98.9 ± 42.6 days. Calving to service intervals in cows with 50.0%, 62.5 - 68.8% and 75.0 - 87.5% exotic blood were 98.7 ± 41.6, 102.9 ± 58.3 and 94.7 ± 33.6 days, respectively. The calving to service interval in cows aged 42 - 60, 61 - 78 and 79 - 173 months was 74.0 ± 14.4, 108.5 ± 48.9 and 100.8 ± 43.0 days, respectively. The calving to service interval in cows with body weight 140 - 180, 181 - 220 and 221 - 250 Kg was 94.3 ± 38.4, 99.3 ± 41.4 and 134.2 ± 74.9 days, respectively. The calving to service interval in cows with BCS 2.5 - 3.0 and 3.5 - 4.0 was 98.8 ± 42.3 and 99.1 ± 44.3 days, respectively. The calving to service interval in cows with parity 1, 2 - 3 and 4 - 10 was 117.5 ± 76.4, 99.6 ± 40.0 and 96.4 ± 41.2 days, respectively. The calving to service interval in cows with milk yield 0 (dry), 1 - 5, 6 - 10 and 11 - 16 litres was 118.4 ± 51.2, 99.6 ± 45.6, 102.5 ± 45.8 and 84.0 ± 22.1 days, respectively. The calving to service interval in suckling and nonsuckling cows was 100.5 ± 44.3 and 88.8 ± 28.8 days, respectively. The calving to service interval in cows in summer, rainy and winter season was 98.8 ± 41.4, 104.5 ± 46.9 and 95.3 ± 41.9 days, respectively. The difference in calving to service interval among cows of different ages was significant (P<0.05). It is suggested that calving to service interval was not influenced by breed, body weight, BCS, parity, milk yield, suckling status or season of service. Bangl. vet. 2021. Vol. 38, No. 1-2, 33–41
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Wood, Peter D. P. "Importance of the calving interval to milk yield in the following lactation of British Friesian cows." Journal of Dairy Research 52, no. 1 (February 1985): 1–8. http://dx.doi.org/10.1017/s0022029900023839.

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SUMMARYThe records of 453260 British Friesian cows, accumulated by the Milk Marketing Board of England and Wales in 1981/82, were used to estimate the effect of the calving interval on milk production in the subsequent lactation. There was a clear relationship between the length of the dry period and the calving interval in which it occurred, such that the dry period was extended by 2·5 d for every 10 d extension of the calving interval. The relationship between the interval and milk production in the following lactation appeared more likely to be due to variation in the dry period than to variation in the calving interval itself. A dry period between 50 and 60 d was associated with maximum production of milk, fat and protein. Among cows with dry periods shorter than 55 d, fat and protein production increased by 8 and 3·5 kg/d respectively. For cows with dry periods longer than 55 d, production of fat and protein was reduced by 0·2 and 0·12 kg/d respectively. The modal calving interval was 355 d including a dry period of 51 d. The interval tended to increase with the age of the cow, at the rate of 3 d/month of age within parity. The best estimate of future calving intervals was the mean of all previous intervals of the cow.
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Farfán Talledo, Alicia Esther, Wilter Fernando Borja Veloz, Luis Santiago Quiroz Fernández, Juan José Zambrano Villacís, and Pablo Roberto Marini. "Desempeño reproductivo de vacas Gyr lechero en un sistema a pastoreo del trópico ecuatoriano." La Técnica: Revista de las Agrociencias. ISSN 2477-8982, no. 24 (December 22, 2020): 99. http://dx.doi.org/10.33936/la_tecnica.v0i24.2337.

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Reproductive performance of Gyr dairy cows in a grazing system of the Ecuadorian Tropic Resumen El objetivo del trabajo fue evaluar la eficiencia reproductiva en vacas lecheras Gyr en condiciones de pastoreo del trópico ecuatoriano. Se utilizaron datos retrospectivos desde el 2016 al 2018 de la Hacienda Casa Blanca del cantón Olmedo provincia de Manabí – Ecuador. Se utilizaron 98 vacas multíparas Gyr para el estudio que tuvieron fecha de parto registrada en los años analizados. El intervalo parto-parto presentó valores promedio de 420,5 ± 7,1 días, días de secas 210,5 ± 7,1 e intervalo parto concepción de 150,5 ± 7,1 días. Se observó que existió una tendencia que los partos no mantengan la misma distribución en el año acumulándose a finales de la época seca. Se concluye que las vacas analizadas, para este establecimiento y años utilizados, mostraron valores más bajos de intervalo entre partos según la bibliografía consultada, aunque aún se debería seguir trabajando para llegar al óptimo de un parto al año. Palabras clave: vacas Gyr; intervalo parto-parto; intervalo parto concepción; días de seca. Abstract The objective of the work was to evaluate the reproductive efficiency through in Gyr dairy cows under grazing conditions of the ecuadorian tropic. Retrospective data from 2016 to 2018 from the Hacienda Casa Blanca canton Olmedo province of Manabí – Ecuador. Were used 98 Gyr multiparous cows were used for the study that had a safe calving date in the years analyzed. The calving-calving interval presented average values of 420,5 ± 7,1 days dry days 210,5 ± 7,1 and calving conception interval of 150,5 ± 7,1 days. It was observed that there was a tendency for calving not to maintain the same distribution in the year, accumulating at the end of the dry season. It is concluded that the cows analyzed, for this establishment and years used, showed lower values of the interval between calving according to the bibliography consulted, although work should still continue to reach the optimum of one calving per year. Keywords: Gyr cows; calving-calving interval; calving-calving interval; dry days.
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Czerniawska-Piątkowska, Ewa, and Oliwia NAGÓRSKA. "EFFECT OF AGE AT FIRST CALVING AND CALVING INTERVAL LENGHT ON MILK PERFORMANCE IN COWS." Folia Pomeranae Universitatis Technologiae Stetinensis Agricultura, Alimentaria, Piscaria et Zootechnica 338, no. 44 (December 30, 2017): 21–26. http://dx.doi.org/10.21005/aapz2017.44.4.02.

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Dissertations / Theses on the topic "Calving interval"

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Ferreira, Joana Filipa da Luz. "Factores com influência nos parâmetros produtivos e reprodutivos numa vacada de raça Alentejana." Master's thesis, ISA, 2014. http://hdl.handle.net/10400.5/6798.

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Mestrado em Engenharia Zootécnica - Produção Animal - Instituto Superior de Agronomia / Faculdade de Medicina Veterinária
It is well accepted that one of the biggest concerns of the beef producers is reducing the calving interval, because of the great impact it has on the productivity of the herd, as well as the productive parameters of their calves. All these factors are influenced by environmental conditions in which the environment and management, namely reproductive and feeding management can be highlighted. The aim of this work was to study the effect of farm, calving number, sex of the calf, year and season of births in the calving interval of the Alentejano cows in two farms (Paço and Pinheiros) belonging to Eugénio de Almeida Foundation. Also, the effects of farm, year and season of birth on the various productive parameters of steers produced were studied. The results obtained indicate the existence of a strong effect of year of birth, probably related to annual rainfall, as well as calving number on the calving interval. Also, the season of birth influenced the lenght of calving interval, revealing that the best seasons are spring and autumn. Also the year and season of birth had influences on the productive characteristics of animals, noting that the summer was clearly the season of births which showed worse results.
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Österman, Sara. "Extended calving interval and increased milking frequency in dairy cows : effects on productivity and welfare /." Uppsala : Dept. of Animal Nutrition and Management, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/a383.pdf.

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Bettencourt, Ana Helena Palma. "A atuação do médico veterinário na maximização reprodutiva de uma vacada de carne intervalo entre partos da raça Mertolenga como caso de estudo." Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2021. http://hdl.handle.net/10400.5/21177.

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Dissertação de Mestrado Integrado em Medicina Veterinária
Este estudo teve como objetivos analisar a distribuição de partos na raça Mertolenga e a influência dos principais efeitos ambientais no intervalo entre partos (IEP) em bovinos da mesma raça. Foram utilizados os registos de 8 explorações de criadores, inscritas no livro genealógico da Associação de Criadores de Bovinos Mertolengos (ACBM), correspondendo a 17 090 partos e 13 510 IEP de 2 655 fêmeas, ocorridos entre 1990 e 2019. Os registos foram submetidos a várias análises preliminares com o programa SAS®, utilizando-se o PROC UNIVARIATE, o PROC MEANS e o PROC FREQ. Com um modelo misto, através do PROC MIXED do mesmo programa, analisou-se o IEP com um modelo que incluiu os efeitos fixos da exploração, ano e mês de parto, sexo e raça do vitelo e como covariável o efeito linear e quadrático da idade ao parto; a fêmea (vaca) foi considerada como efeito aleatório no modelo misto. A idade média ao primeiro parto (IPP) foi de 34,3 meses, a idade média de morte foi de 13,76 anos e o número médio de partos por vaca ao longo da vida foi de 5,3±3,4 partos/vaca. Neste estudo observou-se um IEP médio de 436,9 ±116,2 dias e as variáveis “exploração”, “mês do parto”, “ano do parto”, “raça do vitelo” e “idade da vaca ao parto” influenciaram significativamente o IEP (p<0,0001) enquanto que a variável “sexo do vitelo” não se revelou significativa (p=0,1127). Observou-se que a maior concentração de partos ocorre nos meses de verão, principalmente entre meados de julho e setembro e que existem grandes diferenças nos valores de IEP médios entre as distintas explorações e anos avaliados. Vacas paridas em abril tiveram o IEP médio mais curto (418,9±4,6 dias) e vacas paridas em janeiro e fevereiro apresentaram valores médios de IEP mais longos (451,9±3,5 dias versus 450,315±3,755 dias). Vacas que parem vitelos Mertolengos puros têm, em média, IEP inferiores (421,9) que vacas que parem vitelos cruzados (440,1). Apesar de não existirem diferenças significativas, observou-se que vacas que parem vitelas, em média, têm IEP cerca de 3 dias mais curtos que vacas que parem machos (432,5±1,9 dias versus 429,5±1,9 dias). Em relação à idade ao parto, verificou-se que se trata de uma variável com um efeito quadrático neste parâmetro reprodutivo, sendo que fêmeas mais novas apresentam IEP superiores e que este intervalo vai diminuindo com o avançar da idade das vacas até aos 9,3 anos (112 meses), idade em que se verificou o menor IEP médio (404 dias) e a partir da qual este valor volta a aumentar. Tendo em conta a influência significativa do maneio realizado na vacada no seu IEP médio, é fundamental a sensibilização dos produtores para o papel que o médico veterinário representa para a melhoria da eficiência reprodutiva dos seus efetivos.
ABSTRACT - The role of the veterinarian in the reproductive maximization in beef cattle: calving to calving interval of Mertolenga breed as a case study - This study aimed to analyse the distribution of Mertolenga calving and the influence of the main environmental effects on the calving-to-calving interval (CCI) in cattle of the same breed. The records of 8 farms of breeders, registered in the genealogical book of the Association of Mertolengo Bovine Breeders (ACBM) were used, corresponding to 17 090 births and 13 510 CCI of 2 655 females, which occurred between 1990 and 2019. The records were submitted to several preliminary analyses with the SAS® program, using PROC, PROC MEANS and PROC FREQ. With a mixed model, through the PROC MIXED of the same program, the CCI was analysed with a model that included the fixed effects of the herd, year and month of calving, sex and breed of the calf and as covariable the linear and quadratic effect of age to delivery; the female (cow) was considered as a random effect in the mixed model. The average age at first calving (AFC) observed was 34.3 months, the average age of death was 13.8 years and the average number of births per cow throughout life was 5.3 ± 3,9 calves per cow. In this study, an average IEP of 436.9 ± 116.2 days was observed and the variables “herd”, “month of calving”, “year of calving”, “calf breed” and “cow age at calving” influenced significantly the CCI (p <0.0001) while the variable “calf sex” was not significant (p = 0.1127). It was observed that the highest concentration of births occurs in the summer months, mainly between mid-July and September, and that there are large differences in the mean CCI values between the different farms and years evaluated. Cows calved in April had the shortest CCI average (418.9 ± 4.6 days), and cows calved in January and February had longer CCI values (451,9 ± 3,5 days / 450,3 ± 3,8 days). Cows that calve pure Mertolengos calves have, on average, lower CCI (421,9) that cows that calve crossed calves (440,1). Although there were no significant differences, it was observed that cows that calved female calves, on average, had CCI about 3 days shorter than cows that calved males (432.5 ± 1.9 days / 429.5 ± 1.9 days). Regarding the age at calving, it was found that this is a variable with a quadratic effect on this reproductive parameter and that younger females have higher CCI and that this interval decreases with the advancing age of the cows up to 9.3 years (112 months), age at which the lowest mean CCI (404 days) was observed and after which this value increases again. Bearing in mind the significant influence of the management carried out on the cow in its average CCI, it is essential to raise awareness among producers about the advantages that may arise from improving the reproductive efficiency of their herds and the role that the veterinarian plays to successfully achieve this goal.
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Garcia-Peniche, Teresa Beatriz. "Comparisons of Holstein, Brown Swiss, and Jersey cows for age at first calving, first calving interval, and true herd-life up to five years in seven regions of the United States." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/30203.

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The objectives of this research were to evaluate breed differences for heat-stress resistance using age at first calving and first calving interval, and to assess breed by region interactions for seven regions of the United States for survival-related traits up to five years of age in Brown Swiss, Holstein, and Jersey cows. Age at first calving and first calving interval were studied in farms with two breeds, with Holstein and Brown Swiss or Holstein and Jersey cows. The survival-related traits were analyzed in farms with one or two breeds. Seven regions within the United States were defined: Northeast, Northwest, Central north, Central, Central south, Southwest and Southeast. The fertility traits were also analyzed in seven individual states: Wisconsin, Ohio, Oregon, California, Arizona, Florida, and Texas. Brown Swiss were older than Holsteins at first calving (833 ± 2.4 d vs. 806 ± 2.0 d in regions, and 830 ± 3.1 d vs. 803 ± 2.4 d in states), but Holsteins and Brown Swiss did not differ for first calving interval. Jerseys were younger than Holsteins at first calving and had shorter first calving intervals (P < 0.01). In data from individual states, Holsteins housed with Brown Swiss were older at first calving than Holsteins housed with Jerseys (800 ± 2.7 d vs. 780 ± 2.5 d). Holsteins housed with Jerseys had slightly shorter first calving intervals than Holsteins housed with Brown Swiss, and the interaction of "type of Holstein: with season of the first calving was highly significant (P < 0.01). Region and season effects were smaller for Jerseys than for Holsteins, thus, Jerseys showed evidence of heat-stress resistance with respect to Holsteins. Management modified age at first calving in Holsteins, depending on the type of herd they were located in. Longer calving intervals might have been partly due to voluntary waiting period to breed the cows. The survival-related traits were evaluated up to five years of age. They consisted of stayability, number of completed lactations, days lived, herd-life, and total days in milk. For herds with one breed, the order for stayability to five years of age, from longer to shorter-lived breed was: Brown Swiss, Jersey and Holstein, but for the ratio of days in milk to herd-life the order was: Holstein, Jersey and Brown Swiss, and for the ratio of days in milk to days lived, it was: Jersey, and Holstein and Brown Swiss tied. This last ordering was the same for number of lactations completed by five years of age. The results for two-breed herds were similar since Brown Swiss and Jerseys had larger (Chi-square P < 0.01) probabilities of living past five years of age than Holsteins, and for days in milk and number of lactations completed, Jerseys had higher values than Holsteins (P < 0.01), but Holsteins and Brown Swiss tied in some analyses. Breed by region interaction was always significant. If all other conditions were assumed equal, Jerseys would give fastest returns by five years of age. The overall conclusion is that Jerseys performed better for the traits analyzed, all of them highly influenced by environmental conditions.
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Knob, Deise Aline. "Crescimento, desempenho produtivo e reprodutivo de vacas Holandês comparadas às mestiças Holandês x Simental." Universidade do Estado de Santa Catarina, 2015. http://tede.udesc.br/handle/handle/953.

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Improvement of animal nutrition and management, together with genetic selection for milk yeld, increased the productivity of the herds, especially Holstein cows. On the other hand, characteristics related to fertility, health and longevity were disadvantaged The aim was to compare the development, milk yeld and composition, the health of the mammary gland, the body condition score (BCS), reproductive performance and longevity of crossbred Holstein x Simmental cows with Holstein cows. To obtain the data set two farms were used, one in Bom Retiro in SC and another in Carambeí in PR. For growth evaluation, weight gain of the animals were evaluated monthly. For production and udder health data from the official Dairy Herds Improvement Programs of the farm were used. BCS and body weight estimation were made on the farm with an interval between 60 and 90 days within one year. Information concerning the date of birth, parity date, date and number of inseminations, were obtained from the management software of the farms, generating information regarding the calving interval, days between calving to first service, conception rate, age at first calving. In one of the farms, calving were monitoring to quantify the calving difficulty, in the same farm, information of culling were obtained to determine the survival rate of cows. Data were analyzed by statistical package of SAS, using the MIXED and GENMOD procedures. For growth curve, production and composition of milk, (BCS) and body weight nonlinear regression was used, using the NLIN procedure of SAS and the curves of Gompertz (growth) and Wood (production and composition) were used because of having the lowest mean square. Holstein x Simmental crossbred cows produced more milk 31,8 x 30,4 kg/day (P < 0,05), with higher content of lactose and protein, with no difference for fat content. Holstein cows had higher somatic cell score (SCS) 4.49 x 2.93 (P <0.0001) compared to crossbreed cows. Holstein x Simmental crossbred cows had better BCS during lactation 3.65 x 2.94 (P <0.0001) with no difference in body weight in relation to Holstein cows. For growth of calves and heifers there was no difference between the genetic groups. Crossbred cows Holstein x Simmental had better reproductive performance than the Holstein cows, characterized by lower calving interval (381 x 445 days), higher conception rate (37.31 x 33, 64%) and shorter interval calving to first service (65.6 x 89.3 days). Crossbred cows Holstein x Simmental had higher survival rate than Holstein cows (83 x 92 In conclusion, crossbred cows Holstein x Simmental produce more milk with higher content of lactose and protein, have less ECS and greater BCS without difference for growing of heifers and body weight in adult age. Crossbred cows still have better reproductive performance and have a higher survival rate than the Holstein cows
Melhorias na nutrição e no manejo dos rebanhos bem como a seleção genética para a produção de leite aumentaram a produtividade dos animais. Em contrapartida, características relacionadas a fertilidade, sanidade e longevidade foram prejudicadas. O objetivo foi comparar o desenvolvimento, a produção e composição do leite, a sanidade da glândula mamária, o escore de condição corporal o desempenho reprodutivo e a longevidade de vacas mestiças Holandês x Simental em relação as vacas puras Holandês. Foram utilizadas duas propriedades, uma localizada no município de Bom Retiro em SC e outra em Carambeí no PR. Para avaliação de crescimento o ganho de peso dos animais foi avaliado mensalmente. Para obter dados produtivos e de sanidade de úbere foram utilizados dados do controle leiteiro oficial da propriedade. As avaliações de escore e peso vivo foram realizadas na propriedade com intervalo entre 60 e 90 dias no período de um ano, informações estas obtidas em uma das propriedades. As informações referentes a data de nascimento, data de parto, data e número de coberturas, foram obtidas junto aos software de gerenciamento de ambas as propriedades, gerando informações referentes ao intervalo entre partos (IEP), período parto primeiro serviço, taxa de concepção, idade ao primeiro parto. Em uma das propriedades foi feito o acompanhamento dos partos para quantificar a dificuldade de parto, da mesma forma, foram obtidas informações referentes ao descarte de animais para determinar a taxa de permanência no rebanho das vacas. Os dados foram analisados pelo pacote estatístico SAS, utilizando-se os procedimentos MIXED e GENMOD Para curva de crescimento, de produção e composição do leite bem como escore de condição corporal (ECC) e peso vivo foi utilizada a técnica de regressão não linear, do pacote estatístico SAS sendo que foram utilizadas as curvas de Gompertz (crescimento) e de Wood (produção e composição) por apresentarem o menor quadrado médio do erro. Vacas mestiças Holandês x Simental produziram mais leite 31,8 x 30,4 ( P < 0,05), com maior teor de lactose e proteína, sem diferença para teor de gordura. Vacas Holandês obtiveram maior escore de células somáticas (ECS) 4,49 x 2,93 (P < 0,0001) em relação as mestiças. Vacas mestiças Holandês x Simental obtiveram melhor ECC durante a lactação 3,65 x 2,94 (P < 0,0001) sem diferença para peso vivo em relação as vacas Holandês. Para crescimento de bezerras e novilhas não houve diferença entre os grupamentos genéticos. Vacas mestiças Holandês x Simental obtiveram melhor desempenho reprodutivo em relação as vacas puras, caracterizado através do menor IEP (381 x 445 dias), maior taxa de concepção (37,31 x 33, 64 %) bem como menor intervalo parto primeiro serviço (65,6 x 89,3 dias). Vacas mestiças Holandês x Simental apresentaram maior taxa de permanência no rebanho em relação as vacas puras (83 x 92 %). Conclui-se que vacas mestiças produzem mais leite, com maior teor de lactose e proteína, possuem menos ECS e maior ECC sem diferença para crescimento de novilhas e peso vivo na idade adulta. Apresentam ainda melhor desempenho reprodutivo e maior taxa de permanência no rebanho em relação as vacas puras Holandês
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Resende, Vânia de Jesus Gravito. "O efeito do intervalo entre partos na viabilidade económica das explorações de bovinos de leite." Master's thesis, Universidade de Évora, 2016. http://hdl.handle.net/10174/18428.

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Devido á crise que afeta o setor de leite nos últimos anos e mais recentemente com a eliminação do sistema de cotas leiteira, aliado à instabilidade do preço de leite e à dificuldade de escoamento do produto principal, torna-se de vital importância a (re) análise e monotorização de todos os parâmetros que influenciam a rentabilidade das explorações de leite portuguesas. Sendo a eficiência reprodutiva um dos fatores de destaque na gestão das explorações torna-se importante perceber que influência exerce na rentabilidade das explorações. Este trabalho demostrou, através da análise económica, que o intervalo entre partos (IEP) influencia a rentabilidade das explorações. Na amostra utilizada, verificou-se um efeito significativo para o IEP igual ou inferior a 415 versus superior a 415 dias e para IEP igual ou inferior a 424 versus superior a 424 dias, em indicadores económicos como o saldo proveitosdespesas , margem bruta , margem líquida , taxa de rentabilidade global dos fatores e margem líquida por Kg leite . Aliado ao IEP, a dimensão das explorações também influencia a sua rentabilidade, sendo as explorações com dimensão média de 51 e 100 animais secos as mais rentáveis; Abstract: The effect of calving interval in the economic viability of dairy cattle farms Due to the crisis affecting the dairy sector in recent years and most recently with the elimination of the milk quota system, coupled with the instability of the milk price and the difficulty of disposing of the main product, it is of vital importance to (re)analyse and monitoring of all parameters that influence the profitability of Portuguese dairy farms. As the reproductive efficiency is one of the prominent factors in farm management. it becomes important to understand how it exerts influence on the profitability of farms. This work demonstrated through economic analysis, that the calving interval influences the profitability of farms. In the sample used, there was a significant effect on the IEP equal to or less than 415 versus more than 415 days and for IEP less than or equal to 424 versus more than 424 days in economic indicators such as "income-expenditure balance", "gross margin , "net margin", "global rate of return factors" and "net margin per kg milk . Coupled with the calving interval, the size of holdings also influences their profitability, and farms with an average size of 51 and 100 dry animals are the most profitable.
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Pacheco, Sara Margarida Ferreira. "Estudo de alguns indices reprodutivos em vacaria de bovinos leiteiros." Master's thesis, ISA/UTL, 2013. http://hdl.handle.net/10400.5/5651.

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Mestrado em Engenharia Zootécnica - Produção Animal - Instituto Superior de Agronomia / Faculdade de Madicina Veterinária
With an excellent milk production aptitude, the famous black brindles Friesian is the bovine breed with the greatest expansion in the world. During the past three decades, genetic breeding programs have been implemented in dairy cattle. Therefore, reproductive traits have been poor, leading to a steady increase in milk production. The present study aims to find the relationship between high milk production and reproductive effectiveness of Manuel dos Santos Miranda dairy farm. Data were extracted from headcount records, between 2009 and 2011. Primarily, the factors influencing reproductive traits were identified, in order to reveal its action and find possible improvements. Data were graphically treated to investigate parameters such as calving interval (CI), conception rate (CR), interval between calving and conception (ICC) and interval between calving and first insemination (IC1stAI). Although no differences were found in milk production during the study, the high production shown leads to reproductive traits, such as high CI (475 ± 5 days), CR (3.3), ICC (216.5 ± 8 days) and IC1stAI (109 ± 3 days). In comparison with literature, the results showed differences in the study indexes. These were believed to be mainly caused by low heat detection, inappropriate dairy farm management and inaccurate artificial insemination strategy
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Silva, Rafael Medeiros de Oliveira. "Estimativas de parâmetros genéticos para habilidade de permanência no rebanho e suas associações com características de interesse econômico em vacas da raça gir leiteiro." Universidade Federal de Alagoas, 2012. http://repositorio.ufal.br/handle/riufal/268.

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With the objective of estimating genetic parameters for stayability to 48 and 60 months of age (STAY48 and STAY60) and their association with milk production in the first lactation (P305), age at first calving (AFC) and first calving interval (FCI) data from 3,344 cows from six herds located in the states of Minas Gerais, São Paulo and Paraiba were analyzed. The (co) variances were estimated by Bayesian approach, using bi-characteristics animal models. For STAY48, STAY60 and AFC systematic effects farm-year-season of birth were include with model. For P305 and FCI, the model used included the systematic effects of farm-year-season of calving and age at calving (linear and quadratic) as a covariable. In addition to these systematic effects for all traits were also included the effects of random additive genetic and residual. The mean estimates of heritability were 0.25 ± 0.08, 0.32 ± 0.07, 0.31 ± 0.05, 0.28 ± 0.05 and 0.08 ± 0.04 for STAY48, STAY60, P305, AFC and FCI, respectively. The a posteriori estimates of genetic correlations between STAY48 and P305 AFC and FCI were 0.90 ± 0.10, -0.55 ± 0.24 and 0.64 ± 0.33. The estimated genetic correlations between STAY60 and P305, AFC and FCI were 0.94 ± 0.07, -0.54 ± 0.21 and 0.83 ± 0.18. The genetic and phenotypic correlations estimated between stayability to 48 and 60 months of age and milk production in the first lactation indicate that production in the first lactation may be used as a selection criterion for longevity. Similarly, the selection to reduce the age at first calving can cause, for a correlated response female.
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Com o objetivo de estimar parâmetros genéticos para stayability aos 48 e 60 meses de idade (STAY48 e STAY60) e suas associações com produção de leite na primeira lactação (P305), idade ao primeiro parto (IPP) e primeiro intervalo de partos (PIDP), foram analisados dados de 3.344 vacas pertencentes a seis rebanhos localizados nos estados de Minas Gerais, São Paulo e Paraíba. Os componentes de (co)variância foram estimados por abordagem Bayesiana em análises bi-características. Para as características STAY48, STAY60 e IPP, foram incluídos os efeitos sistemáticos de fazenda-ano-estação de nascimento. Para P305 e PIDP, o modelo utilizado incluiu os efeitos sistemáticos de fazenda-ano-estação de parto e idade da vaca ao parto com covariável (efeitos linear e quadrático) como covariável. Além desses efeitos sistemáticos, para todas as características estudadas, foram considerados os efeitos aleatórios genético aditivo direto e residual. As herdabilidades médias estimadas foram 0,25±0,08, 0,32±0,07, 0,31±0,05, 0,28±0,05 e 0,08±0,04 para STAY48, STAY60, P305, IPP e PIDP, respectivamente. As estimativas a posteriori das correlações genéticas obtidas entre STAY48 com P305, IPP e PIDP foram de 0,90±0,10, -0,55±0,24 e 0,64±0,33. As correlações genéticas estimadas entre STAY60 com P305, IPP e PIDP foram de 0,94±0,07,-0,54±0,21 e 0,83±0,18. As correlações genética e fenotípica estimadas entre a stayability aos 48 e 60 meses de idade e produção de leite na primeira lactação indicam que a produção na primeira lactação pode ser usada como critério de seleção para longevidade. De forma semelhante, a seleção para reduzir a idade ao primeiro parto pode provocar, por resposta correlacionada, em melhorias na longevidade das fêmeas.
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Ramos, Lucas. "Impacto de três manejos reprodutivos na eficiência reprodutiva e econômica de vacas leiteiras em sistema de produção semi-intensivo." Universidade do Estado de Santa Catarina, 2016. http://tede.udesc.br/handle/handle/2360.

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PROMOP
The current scenario of the national milk production is in constant transformation. The current economic situation in the milk production requires producers operate with maximum efficiency to maintain profitability. To achieve maximum production cows should foal at regular intervals. This is only possible if the females becoming pregnant within a restricted period. That way the adoption of simple reproductive management techniques that can promote improved reproductive performance indexes, will provide higher returns to producers with no need for large investments.The objective of this study was to evaluate the impact of three management systems reproductive and economic efficiency of dairy cows in semi-intensive production systems. The cows were selected by reproductive history, production and corporal condition and subjected to a full gynecological examination, including vaginoscopy and ultrasonography between 30-40 days postpartum. The animals were randomly allocated into one of three treatments: 1 - Estrus Detection (ED) - Consists of traditional management of artificial insemination (AI) after spontaneous estrus postpartum. The animals in this group were inseminated on the first estrus after 50 days in milk (DEL), 12 hours after the start of the estrus detection. Treatment 2 - Prostaglandin F2α (PGF2α) - Between 50-60 days postpartum, each cow received a dose of 0.5 mg of d-cloprostenol and marking with marker bat, being inseminated 12 hours after detection of estrus. Cow not entering into heat, they received a second dose of 0.5 mg d-cloprostenol 11 and / or 14 days later. Treatment 3 - FTAI. The FTAI protocol started 50-60 days postpartum by applying (D0) intravaginal progesterone implant and intramuscular (IM) of estradiol benzoate (EB, 2.0 mg). In D8, the implant removed and administered 150μg of PGF2a and 1 mg estradiol cypionate. The FTAI performed 48 hours after implant removal. To verify the effect of treatments on DEL variables for the first insemination, calving to conception interval (IPC) used the analysis of variance followed by Tukey's test. For analysis of the proportion of data (conception rate to first insemination and pregnancy rate to 150 LED) used the analysis of "Deviance" considering 5% significance level. The results showed higher rate of conception after 1˚ artificial insemination (AI), reduced birth-conception interval and economic benefit with the use of FTAI in dairy cows in semi-intensive production systems. The conditions under which the experiment was conducted, can be concluded that FTAI increases the conception rate in the first postpartum AI reduces the interval between calving and first AI and birth-conception range, raises the profitability of dairy farms
O cenário atual da produção leiteira nacional está em constante transformação. A atual situação econômica na produção de leite exige que os produtores operem com máxima eficiência, para manter a rentabilidade da atividade. Para alcançar a máxima produção, as vacas devem parir em intervalos regulares. Esta situação só é possível se as fêmeas tornarem-se gestantes dentro de um período restrito de tempo. Dessa forma, a adoção de técnicas de manejo reprodutivo simples, que possam promover a melhora dos índices zootécnicos reprodutivos, proporcionará maior retorno financeiro aos produtores, sem necessidade de investimentos de grande porte. O objetivo deste trabalho foi avaliar o impacto de três manejos na eficiência reprodutiva e econômica de vacas leiteiras em sistemas de produção semi-intensivo. As vacas foram selecionadas pelo histórico reprodutivo, produtivo e condição corporal e submetidas a um exame ginecológico completo, incluindo vaginoscopia e ultrassonografia entre 30-40 dias pós-parto. Os animais foram alocados aleatoriamente em um dos três tratamentos: Tratamento 1 – Detecção de Estro (DE) - Consiste de manejo tradicional de inseminação artificial (IA) após cio espontâneo no pós-parto. Os animais deste grupo foram inseminados no primeiro cio após os 50 dias em lactação (DEL), 12 horas após a detecção do início do mesmo. Tratamento 2 – Prostaglandina F2α (PGF2α) – Entre 50-60 dias pós-parto, cada vaca recebeu uma dose de 0,5 mg de d-cloprostenol e marcação com bastão marcador, sendo inseminadas 12 horas após a detecção do cio. Vacas que não entraram em cio, receberam uma segunda dose de 0,5 mg de d-cloprostenol 11 e/ou 14 dias mais tarde. Tratamento 3 - IATF. O protocolo de IATF começou entre 50-60 dias pós-parto com aplicação (D0) de implante intravaginal de progesterona e aplicação intramuscular (IM) de benzoato de estradiol (BE; 2,0 mg). No D8, o implante foi retirado e administrado 150μg de PGF2α e 1 mg de cipionato de estradiol. A IATF foi realizada 48 horas após a retirada do implante. Para verificar o efeito dos tratamentos nas variáveis DEL para a primeira inseminação, intervalo parto-concepção (IPC) utilizou-se a análise de variância seguida do teste de Tukey. Para análise dos dados de proporção (Taxa de concepção a primeira inseminação e Taxa de prenhez aos 150 DEL) utilizou-se a análise de “Deviance” considerando o nível de 5% de significância. Os resultados mostraram aumento da taxa de concepção após a 1˚ inseminação artificial (IA), redução do intervalo parto-concepção e benefício econômico com uso de IATF em vacas leiteiras em sistemas de produção semi-intensivo. Nas condições em que foram realizadas o experimento, conclui-se que IATF aumenta a taxa de concepção na primeira IA pós-parto, reduz o intervalo entre o parto e a primeira IA e o intervalo parto/concepção e eleva a lucratividade de estabelecimentos leiteiros
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Silva, Roberta Polyana Araujo da. "Influência de características de tipo sobre o intervalo de partos em vacas da raça Holandesa no Sul do Brasil." Universidade do Estado de Santa Catarina, 2011. http://tede.udesc.br/handle/handle/895.

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The genetic improvement programs for dairy cattle give more focus in production traits, with negative consequences in the genetics for functional traits like fertility, longevity and health. Selection for conformation can minimize the negative effects for some characteristics, like the mammary health, with gains on longevity. Farmers and technicians have used selection for conformation, especially rump, aiming improve fertility, although without scientific evidence of its efficacy. In this way, this work aimed to study the influence of some linear type traits on calving interval in Holstein cows in South of Brazil. The Holstein Cattle Breeder´s Association of Paraná State (APCBRH) supplied the data for this study. Linear type traits with possible influence on fertility (width and rump angle, chest width, body depth, rear leg side view, foot angle and angularity) were studied using a scale from 1 to 9 points. Calving interval (CI) was used as fertility trait. After editing the data comprised linear classification of 23,014 cows, from 248 herds, classified from 2000 to 2010, daughters of 797 sires. Variance components for heritability and genetic correlation were estimated with Restricted Maximum Likelihood method (REML), using MIXED procedure of statistics package SAS. Heritability for type traits and CI were estimated, as well as genetic correlations among type traits and these with CI. For heritability evaluation for CI and genetic correlation of type traits with CI, information about 51,237 calving intervals of 24,740 cows, of 294 herds, calved between 2000 and 2010, daughters of 1,003 sires were utilized. To evaluate the effect of the conformation of the cows in the CI, the cows were divided in three scores for each trait type, with low score (linear classification 1 to 3), middle score (linear classification 4 to 6) and high score (linear classification 7 to 9). Heritability estimates ranged from 0,09 to 0,24, with the lower values for traits of the category legs and feets. Heritability estimation for CI too was of low magnitude (0,05). Genetic correlation estimations among type traits were also, in general, of low magnitude, with the higher value between chest width and body depth (0,52). Rump width and rump angle showed negative genetic correlation (-0,33), with selection for rump width can lead to an increasing in cows with high pins. Genetic correlation estimations between type traits and CI were, mostly, low. The ones with higher genetic correlation with CI were: foot angle (0,41), rear leg side view (-0,36), rump width (-0,33) and angularity (0,32). Rump angle did not show genetic correlation with CI, however, cows with high pins (score 1 to 3) showed phenotypically longer CI, although with discrete differences in relation to cows with intermediate rumps or low pins (2,5 and 4,7 days, respectively). Rump width did not affect the phenotypic value of CI. Selection for this character may lead to few gains for fertility, although with negative effects to rump angle and rear leg side view, due to negative genetic correlations (-0,33 and -0,35, respectively). For angularity, unfavorable genetic correlation with CI was observed and substantially longer CI were related to more angular cows too, particularly in older cows. We concluded that the estimated genetic correlations of some type traits with calving interval provided information for the practice of selection for type , with the purpose of providing improvements in in the reproductive efficiency of dairy herds. The selection order to avoid cows with inverted rump does not determine genetic gain for fertility. However, cows with high pins have reversed phenotypically calving interval slightly longer. Selection for increased width of rump may bring some increase in fertility, however, with negative consequences on the genetic merit of other type traits. Selection for high angularity should be prevent due the reduction of fertility
Os programas de melhoramento genético têm dado maior ênfase à seleção para as características produtivas, com consequências negativas sobre características funcionais, tais como fertilidade, longevidade e sanidade. A seleção para conformação tem conseguido minimizar parcialmente os efeitos negativos para algumas características, como, por exemplo, a sanidade da glândula mamária, com ganhos sobre longevidade. Produtores e técnicos tem utilizado a seleção para conformação, em especial da garupa, com o intuito de melhorar a fertilidade das vacas, faltando, entretanto, a devida comprovação científica de sua eficácia. Neste sentido, objetivou-se estudar a influência de algumas características lineares de tipo sobre o intervalo de partos em vacas da raça Holandesa no Sul do Brasil. Os dados utilizados foram fornecidos pela Associação Paranaense de Criadores de Bovinos da Raça Holandesa (APCBRH). Estudaram-se características lineares de tipo, com possível influência sobre fertilidade (largura e inclinação de garupa, largura de peito, profundidade corporal, pernas vista lateral, ângulo de casco e angulosidade), sendo as mesmas avaliadas na escala de 1 a 9 pontos. O indicador de fertilidade avaliado foi o intervalo de partos (IP). O arquivo utilizado continha 23.014 vacas classificadas no período de 2000 a 2010, oriundas de 248 rebanhos, filhas de 797 touros. Os componentes de variância para a estimativa das herdabilidades e das correlações genéticas foram obtidas pelo método da Máxima Verossimilhança Restrita (REML), utilizando-se o procedimento MIXED do pacote estatístico SAS. Foram estimadas as herdabilidades para características de tipo e IP, assim como as correlações genéticas entre características de tipo e destas com IP. Para estimativa da herdabilidade do IP e das correlações genéticas das características de tipo com o IP foram utilizadas informações de 51.237 intervalos de parto de 24.740 vacas, paridas entre 2000 e 2010, filhas de 1003 touros, pertencentes a 294 rebanhos. Para avaliar o efeito da conformação das vacas, as mesmas foram divididas em três escores de pontuação para cada característica de tipo, sendo escore baixo (pontuação linear de 1 a 3), escore intermediário (pontuação linear de 4 a 6) e escore alto (pontuação linear de 7 a 9). As estimativas de herdabilidade variaram de 0,09 a 0,24, sendo os valores mais baixos para as características da categoria pernas e pés. A estimativa de herdabilidade para IP foi de baixa magnitude (0,05). As estimativas das correlações genéticas entre as características de tipo foram, em geral, de pequena magnitude, sendo o maior valor observado entre largura de peito e profundidade corporal (0,52). As características largura e inclinação de garupa apresentaram correlação genética negativa (- 0,33), sendo que, a seleção para garupa larga poderá levar a um aumento na frequência de vacas com garupa invertida. As estimativas de correlações genéticas entre as características de tipo e IP foram, em sua maioria, baixas. Dentre as características de tipo as que apresentaram maior correlação genética com IP foram: ângulo de casco (0,41), pernas vista lateral (-0,36), largura de garupa (-0,33) e angulosidade (0,32). A inclinação de garupa não apresentou correlação genética com IP, entretanto, vacas com garupa invertida (escore 1 a 3) apresentaram fenotipicamente IP significativamente mais longos, porém com diferenças discretas em relação às vacas com garupa intermediária ou escorrida (2,5 e 4,7 dias, respectivamente). A largura de garupa não afetou o valor fenotípico do IP (P > 0,05). A seleção para esta característica poderia trazer pequenos ganhos para fertilidade, porém com efeitos negativos sobre a inclinação de garupa e pernas vista lateral, devido a correlações genéticas negativas com estas características (-0,33 e -0,35, respectivamente). Para angulosidade, além da correlação genética desfavorável com intervalo de partos, também foram observados IP substancialmente mais longos em vacas mais angulosas, especialmente em vacas mais velhas. Conclui-se que as correlações genéticas estimadas de algumas características de tipo com intervalo de partos fornecem subsídios para a prática de seleção para tipo, com a finalidade de proporcionar melhorias na eficiência reprodutiva dos rebanhos leiteiros. A seleção visando evitar vacas com garupa invertida não determina ganhos genéticos para fertilidade. Entretanto, vacas com garupas invertidas apresentam fenotipicamente intervalos de partos discretamente mais longos. A seleção para aumento da largura de garupa poderá trazer algum incremento em fertilidade, porém, com consequências negativas sobre o mérito genético de outras características de tipo. A seleção para elevada angulosidade deve ser evitada devida à redução da fertilidade
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Books on the topic "Calving interval"

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Matt, Barlow, and Teagasc, eds. Reducing the calving interval in suckler herds. [Dublin]: Teagasc, 1996.

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Book chapters on the topic "Calving interval"

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Kreijkes, Jeannette. "By Miracles or the Internal Witness of the Spirit? Calvin and Chrysostom on the Confirmation of the Gospel." In Calvinus frater in Domino, 271–82. Göttingen: Vandenhoeck & Ruprecht, 2020. http://dx.doi.org/10.13109/9783666540752.271.

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Britt, Jenks Swann. "Achieving a Profitable Calving Interval Through a Reproduction Health and Management Program." In Dairy Science Handbook, 401–9. CRC Press, 2019. http://dx.doi.org/10.1201/9780429049361-39.

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"Life in the Slow Lane: Ecology and Conservation of Long-Lived Marine Animals." In Life in the Slow Lane: Ecology and Conservation of Long-Lived Marine Animals, edited by Milani Chaloupka and Michael Osmond. American Fisheries Society, 1999. http://dx.doi.org/10.47886/9781888569155.ch7.

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<em>Abstract.</em> —The spatial and seasonal distribution of humpback whales in the Great Barrier Reef Marine Park (GBRMP) was defined using data from a systematic aerial surveillance program. The data comprised 414 pod sightings (812 individuals) recorded from July 1982 to March 1996. These sightings were supposedly of humpbacks from the east Australian Group V substock that migrates during the austral autumn from Antarctic feeding grounds to winter breeding grounds in GBR waters. Humpbacks were sighted in all months and throughout the GBRMP. However, most pods (75%) were sighted in southern GBR waters (below 19°S) and mainly during winter and spring ( July to September). Occasional sightings of humpbacks in northern GBR waters (above 16°S) in summer supports previous claims of a substock resident year-round in northern Australian tropical waters. Mother–calf sightings were rare with most recorded below 21°S and mainly in August and September. These limited sightings suggest that the main calving grounds for the east Australian Group V substock occur in the extensive southern GBR lagoonal waters defined northward by the Whitsunday Group of islands and reefs and eastward by the Pompey/Swains reef complex. An estimate of the crude birth rate was 0.072 (95% confidence interval [CI]: 0.06–0.11) with Monte Carlo estimates of the median calving rate at 0.3 calves per mature female per year (95% CI: 0.22–0.43) and the median interbirth interval at 3.4 years (95% CI: 2.3–4.5) indicating low and variable juvenile recruitment. Nonparametric time series analysis (seasonal and trend decomposition using loess, STL) of monthly humpback sightings showed that the long-term trend in sightings was increasing but that there was significant inter-annual variability in the seasonal abundance of humpbacks in the GBRMP. The STL analysis also suggested that the frequency of sightings increased earlier in winter (June) and later in the season during spring/summer (October to December). Time series regression analysis of the STL-derived trend in sightings suggested that the east Australian Group V substock increased slowly in abundance over the 14 years from 1982 to 1996 at about 3.9% per year (95% CI: 1.9% to 5.7%)—a finding consistent with an estimate of low and variable juvenile recruitment.
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Mitchell, Graham. "Reproduction and the Fetus." In How Giraffes Work, 433–80. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780197571194.003.0017.

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The reproductive organs of male and female giraffes are similar to those of all other artiodactyls. Giraffes have 14 pairs of autosomes and a pair of sex chromosomes. A constant testis temperature depends on countercurrent heat exchange between a large pampiniform venous plexus and the testicular artery. The onset of puberty in males and females occurs at ~3 years of age and is marked by enlargement of testes and the onset of oestrous cycles. Oestrus cycles are ~15 days long. Courtship, conception, and pregnancy are delayed until ~5 years of age. The giraffe placenta is polycotyledonous and epitheliochorial. Pregnancy is sustained by progesterone secreted by a single corpus luteum, the placenta and fetal ovaries and testes. Gestation lasts ~450 days and is ended by hormones secreted by the hypothalamic-pituitary axis of a mature fetus. Birth takes ~30 minutes. Daily milk yield ranges between 2.5 L and 10 L. Protein, fat, and lactose are higher than in cow’s milk. Weaning occurs at ~6 months of age. The average calving interval is ~20 months but varies according to the degree of lactational stress itself partly determined by whether a calf survives. Female giraffes have ~8 calves of which ~3 will reach adulthood. Survival of giraffes as a species depends on fewer adults dying each year than the number of calves reaching adulthood.
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Bruening, Michael W. "The Formation of the Farellian and Calvinist Networks." In Refusing to Kiss the Slipper, 36–64. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780197566954.003.0003.

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Guillaume Farel and later John Calvin insisted that religious reform required uncompromising adherence to a particular set of beliefs, initially focused on the Reformed understanding of the Eucharist. This insistence made working within the existing Church completely untenable, and it put them at odds with Lefèvre, Roussel, and the evangelicals who continued to work for internal reform in France. Farel broke from his old friends when he enthusiastically took the Reformed side in the Lutheran-Reformed quarrels over the Eucharist. He moved to Switzerland, where he became an enthusiastic missionary and wrote the first French Protestant liturgy and theological guide. He and his followers also developed arguments against Nicodemism before Calvin did. When John Calvin arrived in Geneva, he altered some of Farel’s early ideas, especially on the Eucharist, predestination, and moral discipline, but he gained followers, notably Farel himself and Pierre Viret.
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Shuger, Debora. "Elizabethan First Editions." In Paratexts of the English Bible, 1525-1611, 122–216. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780192843579.003.0004.

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Chapter 3 treats the first editions of the major Elizabethan bibles. These are “official” bibles, their translation and paratexts, but also their printing, curated by the period’s competing magisteria: Archbishop Parker, the Marian exiles at Geneva, the leadership of the English College at Rheims and Douai; Theodore Beza, Calvin’s successor at Geneva; Pierre L’Oiseleur de Villiers, minister to London’s Huguenot congregation. As their provenance implies, these bibles were intended to set forth the distinctive theological visions of their respective faith communities; indeed the early Elizabethan ones—the Geneva and Bishops’ in particular—provide the earliest articulation of what in retrospect one instantly recognizes as hardline Calvinism and Hooker-style Anglicanism. The Rheims preface opens with an equally recognizable defense of Catholic traditionalism against the bible-spouting impudence of English heretics, but what follows is a quite sophisticated discussion, one without Protestant counterpart, of manuscript transmission, textual variants, and scribal corruption. The first half of the chapter focuses on the opening paratexts laying out these competing visions. The second turns to the myriad internal ones: to the psalm prologues, for example, where the same patristic homily, in the Bishops’ version, bears witness to the religious value of aesthetic pleasure, in the Douai’s, to the apotropaic power of sacramentalia; and to the Geneva’s prologue to Romans, whose account of predestination differs from that laid out in the Romans glosses that immediately follow.
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Conference papers on the topic "Calving interval"

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Gama, L. T., R. Espigolan, F. S. Baldi, J. P. Eler, E. C. M. Oliveira, R. Nuñez-Dominguez, and J. B. S. Ferraz. "647. Breed differences, heterosis and recombination effects for calving interval in a composite beef cattle breed." In World Congress on Genetics Applied to Livestock Production. The Netherlands: Wageningen Academic Publishers, 2022. http://dx.doi.org/10.3920/978-90-8686-940-4_647.

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