Effects of short-term exposure to drinking water contaminated with manure on water and feed intake, production and lying behaviour in dairy cattle

Abstract

This study aimed to assess the effects of water quality (contamination with manure) on water and feed intake and subsuquent milk production, and lying behaviour in dairy cattle. Fifteen lactating Holstein-Friesian cows were provided one of three water treatments in a cross-over design; clean (tap) water, or water contaminated with either 0.5 mg or 1 mg fresh manure/g water. Cows were managed individually in indoor pens and milk production, feed and water intake (free and via feed) and lying behaviour were recorded daily. Live weight was recorded before and after each treatment exposure. Cows were in their pens for 5 days with clean water (baseline) before given one of the three water treatments for 4 consecutive days. Between each baseline/treatment period the cows were managed as one group on pasture for 5 days with clean water to minimize any carry-over effects. This was repeated until all cows had undergone all treatments. Data were analysed using analysis of variance of the 4-day treatment averages and repeated measures analysis of variance to examine day trends within treatment phases. There was an overall treatment effect on free water intake (P < 0.001, SED: 2.34); cows drank more of the clean water (78.0 L/day, range: 49.2–118.0 L) compared to when it was contaminated with 0.5 mg (68.4 L/day, range: 53.5–82.8 L) or 1 mg manure/g water (67.0 L/day, range: 50.6–86.8 L). The water intake of the two contaminated water treatments increased over the 4 days to be the same as the clean water treatment by day 4 (treatment * day interaction, P = 0.002). The cows obtained considerable amount of water from their feed (on average 48 L/day), however, there was no treatment effect on this water intake (P = 0.511). There was no treatment effect on feed intake, live weight or lying behaviour (P ≥ 0.064). Our results show that cows are sensitive to manure contamination of their drinking water. Cows consumed less contaminated water for the first three days of exposure, however, this was not evident on day four, and the reasons for this are unclear. Water quality did not influence feed intake, production or lying behaviour, however, this could be due to the relatively low levels of contamination used, and/or the high water intake from the feed (cut pasture) may have contributed to meeting metabolic requirements to maintain milk production.