ABSTRACT The objective of this study was to evaluate the effect of quantitative feed restriction level on nutrient intake and digestibility, nitrogen balance, efficiency and feeding behavior, and productive performance of F1 Holstein × Zebu cows in late lactation. Sixty F1 Holstein × Zebu cows were used at the stage of late lactation (183.0±17.5 days of lactation) and with initial body weight (BW) of 499±30 kg. The experimental arrangement adopted was the completely randomized design, with five feed restriction levels (3.39, 2.75, 2.50, 2.25, and 2.00% of BW) and twelve cows as replicates for each treatment. The roughage:concentrate ratio was of 75:25 in the total dry matter of the diet. The restriction of dietary supply from 3.39 to 2.0% of BW linearly reduced dry matter intake by 51.74%. The restriction in diet supply linearly increased dry matter digestibility in 13.76%. For each 1% BW restriction in the diet supply for the animals, there was a linear reduction of 3 h in feeding time. Restriction in diet supply of crossbred cows from 3.39 to 2.0% of BW reduced milk production by 24.84%. For each 1% restriction on supply, 2.17 L of milk were not produced. Milk production corrected to 3.5% fat was not altered with the feed restriction. Final BW decreased 41 kg for each percentage unit of diet restriction. Feed efficiency increased 28.72% with feed restriction. For F1 Holstein × Zebu cows in the late lactation, the restriction of dietary supply up to 2.0% of body weight decreases nutrient intake, nitrogen balance, rumination time, and milk production; however, it improves nutrient digestibility and feed efficiency of the animals.

RESUMO. Este trabalho foi realizado para avaliar o comportamento ingestivo de vacas F1 Holandesas x Zebu alimentadas com crescentes níveis de casca de banana. As dietas foram constituídas de 0, 15, 30, 45 e 60% de substituição da silagem de sorgo pela casca. O delineamento experimental foi dois quadrados latinos 5 x 5. As vacas foram submetidas à observação visual após período de adaptação de cada período experimental. Os tempos despendidos com alimentação (4,13 a 5,58 horas dia-1) e ócio (10 a 12,53 horas dia-1) apresentaram efeito quadrático. O tempo gasto com ruminação, número e duração dos períodos de ruminação, mastigações por bolo e bolos ruminados por dia não foram influenciados pelos níveis de casca. O tempo total de mastigação apresentou efeito quadrático, com ponto máximo no nível de 18,58%. Os níveis de casca de banana não influenciaram consumo, ruminação nem mastigação da fibra em detergente neutro. Consumo, ruminação e mastigação da matéria seca apresentaram efeito linear decrescente. A substituição da silagem de sorgo em até 60% por casca de banana na dieta de vacas em lactação reduz o tempo de alimentação e melhora as eficiências de alimentação e ruminação da matéria seca, mantendo a produção de leite das vacas.

ABSTRACT. This study evaluated the feeding behavior of F1 Holstein x Zebu cows fed increasing levels of banana peel. Diets contained 0, 15, 30, 45 and 60% replacement of sorghum silage with banana peel. The experimental design was two 5x5 Latin squares. Cows were subjected to visual observation after adaptation of each trial period. The times spent in feeding (4.13 to 5.58 hours day-1) and in idle (10 to 12.53 hours day-1) presented quadratic effect. The time spent ruminating, number and duration of rumination periods, chews per cud, and numbers of cuds per day were not affected by treatments. The total chewing time showed a quadratic effect, with peak at 18.58% replacement. The banana peel levels did not affect consumption, rumination and chewing neutral detergent fiber. Intake, rumination and chewing of dry matter showed a decreasing linear effect. The replacement of sorghum silage with banana peel up to 60% in the diet for lactating cows reduces the time spent in feeding and improves feeding and rumination efficiencies of dry matter, keeping the milk production of cows.