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This study aimed to evaluate the effects of pasture allowances on forage production, milk yield and composition, and grazing behaviour of Holstein cows during autumn. Thirty-six Holstein cows calving in the autumn were allocated to blocks considering: calving date, bodyweight, and body score. Treatments consisted of three pasture allowances as follows: high (HA; 38.4 kg DM/cow.day), medium (MA; 30.3 kg DM/cow.day), and low (LA; 26.8 kg DM/cow.day) pasture allowances. Forage mass and forage height pre-grazing were similar (P > 0.05) for all grazing targets. Pasture-use efficiency was affected (P < 0.05) by the pasture allowance. The highest and lowest efficiency was obtained with treatments LA and HA, respectively. The neutral detergent fibre content of forage harvesting was affected (P < 0.05) by the pasture allowance, with average of 44.8, 47.0, and 49.4 to HA, MA, and LA, respectively. There was an effect of pasture allowances (P < 0.05) on the milk yield per hectare and milk yield per cow. The highest production was observed in LA (438 L/ha.day) and the lowest in HA (314 L/ha.day). The percentage of milk fat, milk protein, and milk fat (g/cow.day) did not differ (P > 0.05) among pasture allowances. There was effect (P < 0.05) of pasture allowance with higher grazing time (369 min) and lower rumination time (23.3 min) observed to HA. Pasture allowances affected (P < 0.05) the total number of bites/day and bites/min, but did not affect (P > 0.05) bite mass. The pasture managements with low (26.8 kg DM/cow.day) pasture allowances provided better conditions for milk yield per area, likely due to the better grazing efficiency. However, pasture allowance provide little measurable changes on grazing behaviour. This experiment deals with grazing management effects on milk production and grazing behaviour of dairy cows, which is an area of interest to those involved in pasture-based dairy industries. This study aimed to evaluate the effects of pasture allowances on forage production, milk yield and composition, and grazing behaviour, so that the pasture managements with low pasture allowances provided better conditions for milk yield per area and provide little measurable changes on grazing behaviour. Thus, farmers may increase stocking rate to reach higher milk production when lactating dairy cows graze mixed pasture swards. However, the impact of higher stocking rates on the persistence of pasture species needs to be investigated. [ABSTRACT FROM AUTHOR]

Avaliaram-se os efeitos dos níveis de substituição do milho (MI) pela farinha de varredura de mandioca (FV) (25, 50, 75 e 100%) em rações para ovinos, sobre consumo voluntário, digestibilidade total dos nutrientes, balanços de nitrogênio (BN) e de energia (BE), pH e concentração de nitrogênio amoniacal (N-NH3) do líquido ruminal. Foram utilizados quatro carneiros machos, castrados, sem raça definida, com peso médio de 41,4 kg de peso vivo em um ensaio de digestibilidade utilizando o método de coleta total de fezes e urina. Os animais foram mantidos em gaiolas metabólicas, distribuídos em delineamento experimental quadrado latino 4x4. O líquido ruminal foi obtido por meio de sonda esofágica, nos tempos de zero, 2, 4, 6 e 8 horas após à alimentação da manhã. Não houve efeito dos níveis de substituição para os consumos de matéria seca (MS), matéria orgânica (MO), fibra em detergente neutro (FDN), energia e nitrogênio (N), para os coeficientes de digestibilidade da MS, MO, PB, FDN, amido e energia bruta (EB), e para o BN e os teores de NDT. O consumo de amido e EB apresentaram efeito quadrático crescente até o nível de 75% de FV na ração. A concentração de N amoniacal e o pH do líquido ruminal não diferiram em função do nível de substituição do MI pela FV. Concluindo-se que a FV pode substituir totalmente o MI nas rações de ovinos.