The effect of winter food level on compensatory growth of weaned, suckled calves grazed at two sward heights

Abstract

1986). The effect of winter food level on compensatory growth of weaned, suckled calves grazed at two sward heights. ABSTRACTTwo experiments were conducted with weaned, suckled calves to investigate the effect of feeding level during the post-weaning winter on their subsequent performance when continuously grazed on pasture maintained at two sward heights. Low, medium and high levels of winter feeding resulted in winter live-weight gains of 0-31, 0-58 and 0-79 (s.e. 0-027) kg/day (P < 0-001) during the 152-day winter in experiment 1 and 0-44, 0-69 and 0-84 (s.e. 0-029) kg/day (P < 0-001) for 189 days in experiment 2. During summer (93 days in experiment 1 and 87 days in experiment 2) there was a significant effect of winter food level on performance when live-weight gains were 1-10, 1-02, 0-87 and 1-35, 1-23 and 1-19 (s.e. 0-060) kg/day for the low, medium and high winter food levels on the short and tall swards respectively in experiment 1 (P < 001) and 0-86, 0-66, 0-51 and 1-26, 1-18 and 0-91 (s.e. 0090) kg/day in experiment 2 (P < 0-001). The cattle showing compensatory growth had higher herbage intakes and it is postulated that this occurred because of a negative association between body fat and herbage intake. Sward height had a large positive effect on herbage intake and live-weight gain and it is concluded that for maximum intake on ryegrass swards, herbage height should be at least 8 cm. Lower levels of winter live-weight gain delayed the time to slaughter, but allowed cattle to achieve heavier carcass weights at a fixed level of fatness.It is concluded that there is no single optimum winter food level for weaned, suckled calves but that the choice will depend upon several factors, including availability of winter and summer food resources, the length of the winter feeding period, the desired date of slaughter and type of carcass to be produced.

Feed Supplements for Young Dairy Breed Calves After Turn-Out to Pasture: Effect on Weight Gain and Subclinical Coccidiosis in Organic Production Systems

“…No major weight losses were observed following turn-out to pasture in contrast to what is typically observed about 7-14 days after turn-out (Wright et al, 1986). Supplementation with only small amounts of energy ( 1 2 -1 kg/animal/day) may have reduced or avoided weight losses following turn-out in the present experiment.…”

“…Supplementation with only small amounts of energy ( 1 2 -1 kg/animal/day) may have reduced or avoided weight losses following turn-out in the present experiment. Weight losses following turn-out may generally be small in calves, as the few existing experiments concerning weight loss at this time, show greater relative weight loss with increasing liveweight (Wright et al, 1986;Cazcarra & Petit, 1995).…”

Efeito da suplementação com feno de Leucena (Leucaena leucocephala (Lam) de Wit) durante a estação seca sobre o desenvolvimento ponderal de ovinos

“…Os animais que haviam alcançado desempenhos mais modestos (tratamentos A, B e C), durante a estação seca, passaram a apresentar os melhores resultados na estação das águas e, inversamente, os animais que, em virtude da suplementação, haviam apresentado o melhor desempenho durante a estação seca (tratamento D) passaram ao pior resultado na estação das águas, caracterizando com clareza o fenôme-no conhecido como ganho compensatório. Esse ganho ou crescimento compensatório, já observado com bovinos (WRIGHT et al, 1986), parece decorrer, sobretudo, da maior eficiência dos animais mais magros em consumir e transformar alimentos em peso vivo, quando comparados a animais mais gordos. Efetivamente, sabe-se que, em animais adultos, nos quais os tecidos nervoso e esquelético já completaram sua formação, os nutrientes absorvidos são destinados com prioridade à formação de tecido muscular, enquanto a síntese de gordura, que vai constituir o tecido adiposo, depende da ocorrência de excedentes de energia.…”

“…O emprego de alimentos concentrados para essa finalidade, além de ser limitado e controvertido, devido a seu elevado custo, mostra-se geralmente inadequado quando os animais são mantidos a pasto após o período de suplementação, em virtude da ocorrên-cia de ganho compensatório (WRIGHT et al, 1986).…”

Avaliação das carcaças de novilhos F1 Angus-Nelore em pastagens de Brachiaria decumbens submetidos a diferentes regimes alimentares

“…A escolha depende de vários fatores, como disponibilidade alimentar na seca, idade de abate desejável e tipo de carcaça a ser obtida (WRIGHT et al, 1986). Segundo DROUILLARD et al (1991), a variabilidade de ganho compensatório passa por questões como severidade, natureza e duração da restrição e, principalmente, pela interação dos mesmos.…”