Seasonal variation in time budgets and milk yield for Jersey, Friesland and crossbred cows raised in a pasture-based system.

The time budgets and daily milk yield of Jersey and Friesland cows and their crosses were compared in a pasture-based system by recording the time spent grazing, drinking, lying, standing and walking in four seasons of the year (cool-dry, hot-dry, hot-wet and post-rainy). Observations were made from 0800 to 1400 hours on seven cows per breed. Seven observers monitored the cows at 10-min intervals for 6 h using stop watches. Time spent standing was higher (P < 0.05) for Friesland compared to Jersey cows and the crossbred cows during the hot-wet season. Time spent walking differed among the three genotypes with the Jersey spending more time (P < 0.05) in both hot-wet and cool-dry seasons. No differences were noted on time spent lying down (P > 0.05) across the genotypes in the hot-wet season. In the cool-dry season, differences in time spent grazing (P < 0.05) were noted with the Jersey cows spending more time. The Friesland and the crossbred spent more time lying down (P < 0.05) than the Jersey cows in the cool-dry season. No time differences were noted for time spent standing (P > 0.05) in the same season. The Jersey cows spent the longest time walking (P < 0.05) during the cool-dry period. There were seasonal differences in time spent in all activities (P < 0.05). Time spent on grazing was longest in post-rainy season and lowest in hot-wet season. Differences were observed in the time spent lying down (P < 0.05). The longest period was observed in the hot-dry season and lowest in the hot-wet season. Daily milk yield varied (P < 0.05) with breed with the Friesland and Jersey producing higher yields than the crosses. The highest amount was produced in hot-dry and the least in hot-wet season. Milk yield and lying down were positively correlated (P < 0.05) in Jersey and Friesland cows. Standing was negatively correlated with milk yield (P < 0.05) in both Friesland and Jersey cows. No significant relationship was observed for the crossbred cows. It was concluded that the genotypes show different levels of sensitivity to seasons and that a relationship exists between milk yield and time budgets.