Efeito da idade de desmame no desempenho reprodutivo de novilhas de corte expostas à reprodução aos 13/15 meses de idade

Vaz, Ricardo Zambarda; Lobato, José Fernando Piva

doi:10.1590/s1516-35982010000100019

Cited by 10 publications

(8 citation statements)

References 24 publications

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“…These heifers were reared from birth to breeding as described by Vaz & Lobato (2010a), and the first breeding season, from 13-15 months of age to pregnancy diagnosis, was described by Vaz & Lobato (2010b). After March 3 rd , 2006, these 44 heifers grazed on native pasture, and were managed for approximately 60 days before calving on Brachiaria (Brachiaria brizantha cv Marandu) pasture.…”

Section: Methodsmentioning

confidence: 99%

Influence of weaning age on the reproductive efficiency of primiparous cows

2010

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-The effects of weaning age (90 days or 156 days) of female beef calves were evaluated on their subsequent performance from the beginning of the first pregnancy and the end of the second breeding season, at 22/24 months of age. During pregnancy, heifers were managed as a single group on Brachiaria brizantha cv. Marandu pasture; after calving, on bristle oats (Avena strigosa Schreb) and ryegrass (Lolium multiflorum Lam.); and on Brachiaria humidicula pasture during the second reproductive period. The characteristics studied were not influenced by calf weaning age. Heifers submitted to early or conventional weaning weighed 354.5 and 351.9 kg in the post-calving, and 363.4 and 359.2 kg when they weaned their calves. Average daily gain during the breeding season was 0.562 kg, and body condition score was 3.10 and 3.93 at the beginning and end of the experiment, respectively. Average calf birth and weaning weights were not influenced by dam weaning age, and were 28.7 ± 0.74; 86.5 ± 3.26 and 27.4 ± 0.92; 90.3 ± 4.04 kg, respectively, for dams submitted to early or conventional weaning. Dystocia, calving, birth, and weaning rates were not different between weaning ages, with mean values of 29.5; 95.3; 77.3 e 73.4%. Conception rates were 47.9% in the initial third and 40.8% in the second third versus 11.3% in the final third of the breeding season. Heifer average age at conception was 438 and 434 days for early weaning and conventional weaning.Pregnancy rates and production efficiency estimates at calving and calf weaning were not affected by heifer weaning age. Heifer early weaning did not affect their subsequent performance until the end of the second breeding season, at 22/24 months of age.Key Words: body condition, early weaning, heifers, pregnancy rate, weaning age, weight gain Influência da idade de desmame na eficiência reprodutiva de vacas primíparas RESUMO -Avaliaram-se os efeitos da idade de desmame (aos 90 dias e aos 156 dias) de bezerras de corte sobre o seu desempenho subsequente entre o início da primeira gestação e o final do segundo período reprodutivo, aos 22/24 meses de idade.Durante a gestação, as novilhas foram manejadas em grupo único em pastagem de Brachiaria brizantha cv. Marandu; após o parto, em pastagem de aveia (Avena strigosa Schreb) e azevém (Lolium multiflorum Lam.); e, no segundo período reprodutivo, em pastagem de Brachiaria humidicula. As características estudadas não foram influenciadas pela idade de desmame das bezerras. Os pesos vivos pós-parto foram de 354,5 e 351,9 kg e, ao desmame de seus bezerros, 363,4 e 359,2 kg para as bezerras submetidas aos desmames precoce e convencional. O ganho de peso médio diário no período reprodutivo foi 0,562 kg e o escore de condição corporal, de 3,10 no início e 3,93 no final do experimento. Os pesos médios dos bezerros no nascimento e no desmame não foram influenciados pela idade de desmame das mães, com valores de 28,7 ± 0,74; 86,5 ± 3,26 e 27,4 ± 0,92; 90,3 ± 4,04 kg, respectivamente, para as mães submetidas aos desmames precoce e con...

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Section: Methodsmentioning

confidence: 99%

Influence of weaning age on the reproductive efficiency of primiparous cows

2010

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“…Body weight loss when cattle are grazing natural pastures during periods of low pasture allowance and quality is normal, mainly due to low allowance (Pilau & Lobato, 2006;Vaz & Lobato, 2010a). Menegaz et al (2008) obtained 0.189-kg/day weight gain during the period of June 11 to July 08, but with an initial allowance of 2520-kg DM/ha.…”

Section: Resultsmentioning

confidence: 99%

“…Increasing body condition reflects the sufficient energy to supply animal requirements, influencing weight gain and accelerating fat deposition. There is a strong relationship between body weight and body condition score in heifers due to the significant need for muscle tissue accretion, as they are still growing (Pilau & Lobato, 2006;Vaz & Lobato 2010a).…”

Section: Resultsmentioning

confidence: 99%

Natural and improved pastures on growth and reproductive performance of Hereford heifers

2012

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-This study evaluated yearling growth and reproductive performance of Hereford heifers at 24-26 months of age grazing on natural pastures at two stocking rates during winter and spring, associated or not to improved natural pastures.Heifers were classified according to three weight groups (Light, Medium and Heavy) and randomly distributed into four feeding management practices: 0.6 AU (1 animal unit = 450-kg body weight) -heifers on natural pastures at a stocking rate of 0.6 AU/ha; 0.8 AU -heifers on natural pastures at a stocking rate of 0.8 AU/ha; 0.6 AUI -heifers on natural pastures at a stocking rate of 0.6 AU/ha and on improved natural pastures between Sept 1 st and Nov 1 st ; 0.8 AUI -heifers on natural pasture at a stocking rate of 0.8 AU/ha and on improved natural pastures between Sept 1 st and Nov 1 st . The stocking rate of 0.8 AU resulted in significant weight loss during winter months (-0.138 and -0.356 kg for 0.6 and 0.8 AU, respectively). Heifers grazing during the spring on improved natural pastures presented higher weight gain before the breeding season and higher body weight and body condition score in the beginning and end of the breeding season in relation to those grazing only on natural pastures. Heifers kept at 0.6 AU/ha obtained 69.7% pregnancy rate, which was significantly higher than the 54.2% of those managed at 0.8 UA/ha.Heifers grazing on improved natural pastures during the spring achieved 83.8% pregnancy rate, whereas those maintained on natural pastures achieved only 40.2%. Light and medium heifers lost less weight during the winter as compared with the heavy ones, but weight differences between groups remained until the end of the breeding season. Heavy heifers have higher pregnancy rates. Heifers submitted to lower stocking rate and those grazing on improved natural pastures conceive earlier.

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“…A reprodução em bovinos de corte está relacionada ao ganho de peso e ao estado corporal das fêmeas. Novilhas prenhes ao final do primeiro período reprodutivo são as mais pesadas e as de melhor condição corporal (Restle et al, 1999b;Semmelmann et al, 2001;Rocha & Lobato, 2002;Vaz & Lobato 2010a).…”

Section: Resultsunclassified

Desempenho de novilhas de corte até o parto recebendo diferentes níveis de suplementação durante o período reprodutivo, aos 14 meses de idade

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RESUMO -Avaliou-se o desempenho de novilhas de corte até o parto submetidas a diferentes níveis de suplementação em pastagem natural durante o primeiro período reprodutivo, dos 14 aos 17 meses. Foram utilizadas 98 novilhas contemporâneas do mesmo rebanho dos grupos genéticos Charolês, Nelore e suas cruzas, com peso médio de 255 kg. As novilhas foram distribuídas em três grupos: sem suplementação; com suplementação de 3,5 g/kg do peso corporal; com suplementação de 7,0 g/kg do peso corporal. O peso ao final e o ganho de peso médio diário durante o período de suplementação foi maior entre as novilhas do grupo com suplementação na proporção de 7,0 g/kg (322 e 0,701 kg) em comparação àquelas sob suplementação na proporção de 3,5 g/kg (302 e 0,464 kg) e sem suplementação (288 e 0,425 kg), que não diferiram entre si. O escore de condição corporal ao final da suplementação diferiu entre os três grupos com 3,07; 3,33 e 3,47 pontos, respectivamente, para novilhas sem suplementação; com suplementação na proporção de 3,5 g/kg do peso corporal; com suplementação na proporção de 7,0 g/kg do peso corporal. A porcentagem de prenhez foi influenciada significativamente pelo nível de suplementação, sendo de 35,0; 34,2 e 70,0%, respectivamente. Os dois grupos sob suplementação tiveram maior taxa de concepção na metade inicial do período reprodutivo. A média de idade das novilhas ao parto foi de 785, 778 e 761 dias, respectivamente. O ganho médio diário e a condição corporal foram semelhantes entre as novilhas dos dois grupos genéticos, porém o peso ao início e ao final do período de suplementação foi maior nas filhas de touros charoleses em relação às de touros nelores, refletindo-se nas taxas de manifestação de estro (68,8 vs. 38,2) e de prenhez (60,9 vs. 26,5). As características relacionadas ao parto das novilhas não foram influenciadas pelos níveis de suplementação durante o período reprodutivo. A suplementação durante o período de acasalamento aumenta o desempenho reprodutivo de novilhas aos 14 meses de idade.Palavras-chave: Charolês, condição corporal, ganho médio diário, Nelore Performance of beef heifers until calving receiving different levels of supplementation during the breeding season, at 14 months of age ABSTRACT -The objective was to evaluate the performance of beef heifers until calving receiving different levels of supplementation on native pasture during the first breeding season, from 14 to 17 months: no supplementation; 3.5 g/kg of body weight; and 7.0 g/kg of body weight. Ninety-eight Charolais, Nellore and their crosses, with average initial weight of 255 kg, were used. Weight at the end and average daily weight gain during the supplementation period were higher for 7.0 g/kg of supplement heifers (322 and 0.701 kg) compared to those with 3.5 g/kg of supplement (302 and 0.464 kg) and heifers without supplementation (288 and 0.425 kg), which did not differ from each other. Body condition score at the end of the supplementation was different between the three treatments, being 3.03, 3.33 and 3.47 points for heif...

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Efeito da idade de desmame no desempenho reprodutivo de novilhas de corte expostas à reprodução aos 13/15 meses de idade

Abstract: Early weaning did not affect the heifer reproductive performance at 13/15 months old.

Cited by 10 publications

References 24 publications

Influence of weaning age on the reproductive efficiency of primiparous cows

Influence of weaning age on the reproductive efficiency of primiparous cows

Natural and improved pastures on growth and reproductive performance of Hereford heifers

Desempenho de novilhas de corte até o parto recebendo diferentes níveis de suplementação durante o período reprodutivo, aos 14 meses de idade

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