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Milk performance and grazing behaviour of dairy cows in response to pasture allowance

Author:
Zanine, A. M., Motta, G. P. R., Ferreira, D. J., de Souza, A. L., Ribeiro, M. D., Geron, L. J. V., Fajardo, M., Sprunk, M., Pinho, R. M. A.
Source:
Animal production science 2019 v.59 no.4 pp. 749-756
ISSN:
1836-0939
Subject:
Holstein, autumn, body weight, calving, dairy cows, forage, forage production, grazing, harvesting, milk, milk fat, milk proteins, milk yield, neutral detergent fiber, pasture management, pastures, rumination
Abstract:
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.
Agid:
6315748