Dias ao Parto de Fêmeas Nelore de um Experimento de Seleção para Crescimento: I - Modelo de Repetibilidade

Mercadante, Maria Eugênia Zerlotti; Packer, Irineu Umberto; Razook, Alexander George; Cyrillo, Joslaine Noely dos Santos Gonçalves; Figueiredo, Leopoldo Andrade de

doi:10.1590/s1516-35982002000700014

Cited by 11 publications

(9 citation statements)

References 23 publications

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“…The Canchim SC12 and W12 means in our study agreed with those previously reported for the same Canchim herd (Gianlorenço et al, 2003;Talhari et al, 2003) and the DC HC , DC PHC , DFC and DFC P means were similar to values reported for Nelore beef cattle (Pereira et al, 2001;Mercadante et al, 2002;Forni and Albuquerque, 2005). Furthermore, the WC mean in our study was similar to that reported for ½ Canchim + ½ Nelore females (Alencar et al, 1999) and the WBS mean was only a little higher than that reported for Nelore cattle (Mercadante et al, 2004).…”

Section: Resultssupporting

confidence: 91%

“…We also found that the model 1 DC estimated heritability calculated without penalized data, was low at h 2 = 0.04 for cows only and h 2 = 0.05 for heifers plus cows (Table 2) and similar to the lower limit (h 2 = 0.02 to h 2 = 0.09) of the heritability estimates reported by Mercadante et al (2002) and Forni et al (2003) using models which included permanent environmental effects. Furthermore, our model 2 DC P heritability estimates using penalized data were also low at h 2 = 0.03 for cows only and h 2 = 0.05 for heifers plus cows (Table 2) and were lower than the h 2 = 0.07 to h 2 = 0.16 reported by other workers (Meyer et al, 1991;Johnston and Bunter, 1996;.…”

Section: Resultssupporting

confidence: 84%

“…Our Canchim DFC (h 2 = 0.22 ± 0.07) and DFC P (h 2 = 0.15 ± 0.05) heritability estimates were higher than the Nelore date of first calving heritability (h 2 = 0.11) obtained by Gressler et al (2000) and the Nelore DFC and DFC P heritability (h 2 = 0.07 in both cases) reported by Mercadante et al (2002). It can be seen that in our study the inclusion of females which did not calve decreased DFC heritability 1072 Genetic analyses of Canchim cattle (Table 2), contrasting with the results reported by Mercadante et al (2002) who found that heritability was the same for both DFC and DFC P . Our DFC heritability estimates suggest that this trait presents sufficient genetic variation to respond to selection.…”

Section: Resultscontrasting

confidence: 73%

“…We also found that with the penalization DFC heritability decreased from h 2 = 0.22 to h 2 = 0.15 (Table 2), but due to high standard errors this difference may not be significant. Mercadante et al (2002) reported that DC heritability increased from h 2 = 0.02 to h 2 = 0.12 with the inclusion of non-calving heifers and cows, although for DFC heritability these workers did not find the effect of inclusion or exclusion of noncalving heifers.…”

Section: Resultsmentioning

confidence: 92%

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Genetic analyses of days to calving and their relationships with other traits in a Canchim cattle herd

et al. 2007

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Heritabilities and genetic correlations in a Canchim beef cattle herd were estimated using data on the following traits: male scrotal circumference at twelve months (SC12); days to first calving (DFC) for heifers; days to calving (DC) for cows; male and female weight (W) at twelve months (W12); heifer weight at the start of the first breeding season (WFBS) and at first calving (WFC); and cow weight at the start of the breeding season (WBS) and at calving (WC). Analyses of the DFC and DC traits were carried out excluding and including penalized (DFC P and DC P ) non-calving females. The restricted maximum likelihood method was used, applying one-trait models for the DFC and DC analyses and two-trait models for analyses of DFC and DC combined with the other traits studied. Statistical models included fixed and additive direct random effects for all traits, maternal permanent environmental random effect for SC12 and W12, and the animal permanent environmental random effect for DC P , WBS and WC. We found that DFC and DC values can be improved by selecting for an increase in the SC12. Genetic correlations between DFC and W12 and between DC and W12 indicated that selection for increased W12 may increase DFC but does not produce significantly correlated responses in DC. Associations of the other body weight traits with DC and DFC suggest that heavier females experience lower reproductive performance.

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Section: Resultssupporting

confidence: 91%

Section: Resultssupporting

confidence: 84%

Section: Resultscontrasting

confidence: 73%

Section: Resultsmentioning

confidence: 92%

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Genetic analyses of days to calving and their relationships with other traits in a Canchim cattle herd

et al. 2007

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“…No ano anterior, as novilhas no período pré-acasalamento, com idade de 18 aos 24 meses, passaram por um longo período seco, com déficit pluviométrico anual de 50%, o que pode ter comprometido o ganho de peso e o desempenho reprodutivo futuro. Mercadante et al (2002), em um rebanho considerado controle, observaram, em maior disponibilidade de forragem, embora sem diferença estatística (P>0,05), menor DPP que o determinado em um rebanho considerado seleção (328 ± 2 x 333 ± 1 dias, respectivamente).…”

Section: Resultsunclassified

Desenvolvimento e desempenho reprodutivo de novilhas Nelore criadas a pasto nos cerrados do Centro-Oeste brasileiro

et al. 2006

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RESUMO -Foi simulado e validado um modelo de cria e recria a pasto de fêmeas Nelore nos cerrados do Centro-Oeste brasileiro. Foram determinados os ganhos de peso médios diários (GMD) durante três anos: na primeira seca após a desmama, em pastagem de Brachiaria brizantha (Hochst) Stapf., no período das águas e na segunda seca, em pastagem de Panicum maximum cv. Tanzânia. Os GMD foram: 0,020; 0,550 e 0,172 kg, respectivamente. No segundo período das águas, fase de cria, as novilhas pastejaram em Brachiaria decumbens Stapf. Aos 24,33 meses de idade, as novilhas apresentaram peso vivo (PV) médio de 299 kg e no início do acasalamento, 25,51 ± 0,99 meses de idade (CV = 3,50%) e PV de 309,33 ± 19,19 kg (CV = 6,20%). A parição ocorreu aos 326,71 ± 19,98 dias (CV = 6,11%) após o início da estação de acasalamento, aos 36,26 meses de idade. A taxa média de prenhez foi de 88,4%. As novilhas prenhes foram 25,58 ± 9,97 dias mais velhas e 9,8 ± 7,04 kg mais pesadas que as não-gestantes. Os pesos vivos e as condições corporais no meio do período de acasalamento foram de 360 ± 31,00 kg e 2,94 ± 0,60; antes da parição, de 436 ± 30,86 kg e 4,57 ± 0,40; e na desmama dos bezerros, de 369 ± 33,89 kg e 3,11 ± 0,64.Verificaram-se taxa média de desmama de 75,6%, PV de 158 ± 20,1 kg e idade dos bezerros à desmama de 202 ± 16,6 dias.Novilhas Nelore recriadas em pastagens, com serviço aos 24/26 meses de idade em pastagem de Brachiaria decumbens, tiveram alta produtividade.Palavras-chave: cria e recria de fêmeas, peso à desmama, peso e idade à primeira cria, taxa de desmama, taxa de prenhez Growth and reproductive performance of grazing females Nellore on cerrado of Central BrazilABSTRACT -A model fitted to grazing females Nellore during the rearing periods of the Cerrado Region of Central Brazil was simulated and validated in this study. Body weight gain (BWG) was determined during three years as follows: 1) first dry season after weaning on Brachiaria brizantha (Hochst) Stapf., 2) rainfall season and 3) second dry season both on Panicum maximum Jacq. cv. Tanzânia and averaged 0.020, 0.550, and 0.172 kg, respectively. In the second rainfall season during the rearing period heifers grazed Brachiaria decumbens Stapf. At 24.33 months of age the heifers body weight (BW) averaged 299 kg while in the beginning of the mating season their age and BW averaged, respectively, 25.51 ± 0.99 months (CV = 3.50%) and 309.33 ± 19.19 kg (CV = 6.20%). On average, animals calved 326.71 ± 19.98 days (CV = 6.11) after the beginning of the mating season and 36.26 months of age. The mean pregnancy rate was 88.4%. The pregnant heifers were 25.58 ± 9.97 days older and 9.8 ± 7.04 kg heavier than those non-pregnant. The mean BW and body condition in the middle of the mating season were 360 ± 31.00 and 2.94 ± 0.60, before calving 436 ± 30.86 kg and 4.57 ± 0.40, and at weaning 369 ± 33.89 kg and 3.11 ± 0.64, respectively.The mean weaning rate was of 75.6%. Calves mean BW and age at weaning were of 158 ± 20.1 kg and 202 ± 16.6 days, respectively.Nellore heifers grazi...

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Evidence of negative relationship between female fertility and feed efficiency in Nellore cattle1,2

Ferreira¹,

Bonilha²,

Monteiro³

et al. 2018

Journal of Animal Science

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The objective of this study was to evaluate phenotypic and genetic relationships between fertility traits and feed efficiency in male and female Nellore cattle. Data from 320 females born between 2004 and 2011 were used for phenotypic evaluation. These animals were evaluated for postweaning residual feed intake (RFI) and classified as negative (RFI < 0, mean = -0.294 ± 0.017 kg DM/d) or positive RFI (RFI > 0, mean = 0.305 ± 0.0189 kg DM/d). Of these, 118 prepuberal heifers were submitted to ultrasonography of the uterus and ovaries for monitoring the presence (or absence) of a corpus luteum and for the measurement of endometrial thickness. The following fertility traits were evaluated in all females: age at first calving, days to calving, first calving interval, calving success, stayability, and longevity. The variance components were estimated by the average information restricted maximum likelihood method under an animal model in 5-trait analysis of backfat and rump fat thickness, scrotal circumference, days to calving, and RFI. The total number of animals with records was 6,718, including 927 males with records of scrotal circumference and RFI and 264 females with records of days to calving and RFI. Negative RFI females consumed 12.5% less DM daily than positive RFI females and had a lower rump fat thickness when evaluated postweaning. Among the fertility traits studied, only first calving interval differed (P = 0.0858) between RFI classes, with the interval of negative RFI females being 45 d shorter than that of positive RFI animals. The heritability estimates were 0.29, 0.34, 0.50, 0.12, and 0.16 for backfat and rump fat thickness, scrotal circumference, days to calving, and RFI, respectively. The genetic correlations between RFI and the other traits studied were unfavorable for selection and were of moderate magnitude with backfat thickness, rump fat thickness, and days to calving (0.53, 0.37, and -0.49, respectively) and close to zero with scrotal circumference (0.07). Scrotal circumference (0.17 and 0.15) and days to calving (-0.10 and -0.22) were weakly and favorably correlated with backfat and rump fat thickness. There is evidence of moderate genetic antagonism between female fertility and feed efficiency, but with no evidence of a genetic correlation between male fertility and feed efficiency. There is also evidence of low genetic synergism between fat thickness and fertility.

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Dias ao Parto de Fêmeas Nelore de um Experimento de Seleção para Crescimento: I - Modelo de Repetibilidade

Cited by 11 publications

References 23 publications

Genetic analyses of days to calving and their relationships with other traits in a Canchim cattle herd

Genetic analyses of days to calving and their relationships with other traits in a Canchim cattle herd

Desenvolvimento e desempenho reprodutivo de novilhas Nelore criadas a pasto nos cerrados do Centro-Oeste brasileiro

Evidence of negative relationship between female fertility and feed efficiency in Nellore cattle1,2

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