Diferentes horários de fornecimento de ração para vacas em lactação durante a época quente do ano

Abstract

The objective was to evaluate the effect of different schedules of feed delivery (14h00; 14h00 and 20h00, 16h00, 18h00) during the hot time of year in the semiarid region, on the ingestive behavior and physiological parameters, intake and digestibility of nutrients, milk production and composition, microbial protein production in dairy cows. Regardless of the schedules of feed delivery, all animals received the first feeding of the day at 6h00. Eight crossbred cows with average body weight of 600 kg, with average daily production of 20.0 kg of milk and average initial lactation period of 70 days were used. The schedules of feed delievery did not affect (P> 0.05) the feeding times (313.9 min/day), idleness (502 min/day), rumination (563.6 min/day), and water intake (60.5 min/day). There was no effect of feed delivery schedules on intake and digestibility of dry matter (19.75 kg/day and 67.7%), crude protein (3.17 kg/day and 70.94%), organic matter (18 73 kg/day and 69.35%), NDF (6.05 kg/day and 44.5%). Milk production (20.6 kg/day), milk production corrected for 4% fat (20.63 kg/day), fat (4.03%) and protein (3.57%) contents, plasma urea (31.95 mg/dL), milk urea (10.74 mg/dl), microbial protein production (1314.9 g/day), efficiency of microbial protein synthesis (92.83 g CP/kg TDN), rectal temperature (38,49 °C), respiratory rate (53.82 mov/min), sweating rate (104.6 g/ m²/hour) were not affect by feed delievery schedules. However, at 14h00 and 16h00 the cows showed higher temperatures epidermis and hair coat surface (P <0.05), with mean values of 33.5 °C and 32.35 °C, respectively. It is recommended to feed delivery at any of the studied times.