Drinking water intake, milk production, and grazing behaviour of alpine dairy goats in response to daytime water restriction on temperate pastures

Abstract

Certain local breeds of goats have adapted to severe water restriction in arid and semi-arid regions, but little is known about the adaptability of high-producing dairy goats to water restriction while grazing under temperate conditions. The aim of this study was to assess effects of water restriction of lactating Alpine goats during the daytime at pasture (8 h/d) on herd-level drinking water intake and individual milk production and grazing time. Goats remained in the barn between evening and morning milkings, where each animal was offered 600 g of concentrate and 400 g of hay each day, with free access to water. Twenty four goats were used in a crossover design, for two consecutive 14-d periods. The study was conducted in early summer, with a daily mean ambient temperature of 18.2 ± 3.5 °C (range of 13-27 °C over all the study days), a mean temperature-humidity index of 64 ± 4.9 (range of 56-76). Goats had access to a high-quality multispecies pasture with a mean of 216 ± 44 g DM/kg fresh matter. Total drinking water intake averaged 5.57 L/d and did not differ significantly between treatments. Goats with water access at pasture drank a mean of 1.88 L of water per day during the grazing period, but drank 2.24 L less per day in the barn than goats without water access at pasture. Drinking water intake increased by 0.57 L per day for each °C increase in daily mean ambient temperature. Daily milk production, milk composition, body weight, and daily grazing time did not differ between treatments. Only the duration of the first morning meal at pasture differed significantly between treatments. Thus, water restriction for 8 h per day during grazing periods does not seem to influence the variables measured for Alpine dairy goats under temperate conditions.

Keywords: Dairy goat; Drinking; Grazing pattern; Lifecorder; Temperature.