Effect of short period feed supplementation during early lactation on performance of cows and calves raised in extensive system

Abstract

-Thirty-two multiparous Angus cows at moderate body condition score (3 in a 1-5 scale) received feed supplementation at the beginning of lactation for a short time to determine the effect on milk yield and composition and on performance of cows and calves. Supplementation started on days 22 ± 3.2 after calving. The cows were randomly distributed into two groups (n =16), one group receiving feed supplementation for 35 days (supplemented group), and the other without supplementation (control group). Each cow received 0.6% of its body weight in individual troughs daily. Both groups were kept in native pasture condition during supplementation period. Milk yield evaluation, performance of cows and calves were controlled on day 0 (initial), day 14 (middle) and day 35 (final) of the supplementation period. There was no effect of feed supplementation on milk yield or on any other milk component in both groups, and on calf performance as well. Milk composition differed among periods, when fat was the highest in the middle of supplementation and lactose was the highest in the end of the period. Supplemented cows presented more daily average weight gain at the final period of supplementation than cows from the control group. Beef cow with moderate body condition score can gain weight during the lactation period as a response to increase of energy availability in a short period without any influence on milk production and composition as well as a consequence on calf performance.Key Words: milk yield, post-calving performance, supplementation Efeito da suplementação alimentar por um curto period durante o início da lactação sobre o desempenho de vacas e bezerros de corte criados extensivamente RESUMO -Trinta e duas vacas Angus multíparas em escore de condição corporal moderada (3 em escala de 1 a 5) receberam suplementação alimentar no início de lactação, por um período curto, para determinar o efeito sobre a produção e composição do leite e o desempenho de vacas e bezerros. A suplementação teve início aos 22 ± 3,2 dias após o parto, as vacas foram distribuídas aleatoriamente em dois grupos (n = 16), um recebendo de suplementação alimentar durante 35 dias (grupo suplementado), o outro sem suplementação (grupo controle). Cada vaca recebeu diariamente 0,6% de seu peso corporal em cochos individuais. Ambos os grupos foram mantidos em condição de pastagem nativa durante o período de suplementação.A avaliação da produção de leite, desempenho ponderal de vacas e bezerros foram controlados no dia 0 (início); dia 14 (meio) e dia 35 (final) do período de suplementação. Não houve efeito da suplementação alimentar na produção de leite ou de qualquer componente do leite em ambos os grupos, bem como sobre o desempenho de bezerros. Composição do leite foi diferente entre os períodos, onde a gordura foi maior no meio da suplementação e lactose foi maior no final deste período. Vacas suplementadas apresentaram maior ganho de peso médio diário no período final da suplementação do que as vacas do grupo controle. Vacas de corte em esc...

Performance Efficiency of Pasture-raised Primiparous Beef Cows of Three Different Biotypes and Two Milk Production Levels

“…Although this difference was not significant (P < 0.05), it something that should be consider in the whole system. This result is in accordance with several studies which suggested a lower reproductive efficiency in cows that produce more milk [2,9,18]. According to NRC [27], the energy requirement for maintenance of higher milk production cows is greater than that of lower milk production.…”

“…It is expected that each cow in herd wean approximately 50 to 60% of their weight, which would represent one calf/cow/year to be considered efficient. This production level is difficult to reach in range systems once the nutritional plan can be limited by climate influences and the low forage production, which are reflected by high stocking rates used by producers [9]. Therefore, it is important to understand how different beef cows respond to the pre and postpartum management process, their requirements as well as, their adaptation to range systems, which will eventually contribute to increase in conception rates during the following breeding season.…”