Sheep Ingestion of Water Containing Quebracho or Black Wattle Tannin

Abstract

Ingestion of small amounts of condensed tannin (CT) by ruminants can produce valuable outcomes such as improved nitrogen use and reduced bloating, methane output, and gastrointestinal parasitism. However, many grasses and forbs contain little if any CT. The specific types of CT vary in plants and can have somewhat different effects on ruminants. Individual ruminants can respond differently to CT intake. Not all livestock will consistently consume supplements while grazing, but they all usually drink water daily. Therefore, in order to determine how sheep would respond to CT in their drinking water, eight lambs with the same initial weight of 43 kg were individually penned, fed alfalfa pellets twice daily, and had ad libitum access to two waters. Water intake was measured daily. After an adjustment period to pens, feeding, watering conditions, and water containing CT, three sequential week-long trials were conducted. In Trial 1, lambs chose between tap water and a quebracho tannin (QT)–water mixture (0.19% QT w/w; ca. 1% dry matter intake of QT). In Trial 2, lambs chose between tap water and a QT–water mixture of lower concentration (0.14% QT w/w). In Trial 3, lambs chose between a QT–water mixture and a wattle tannin–water mixture, both with the same concentration (0.14% CT w/w). In Trials 1 and 2, lambs had inconsistent intakes of tannin water and tap water from day to day (P#0.02) and neither preferred nor avoided tannin solutions. They also had inconsistent daily intakes of the two different tannin solutions offered simultaneously (P 5 0.01), and showed no preference for either tannin solution (P$0.15). Results support other observations that sheep will voluntarily consume water with small amounts of CT in it, and provide no evidence that sheep prefer consuming small amounts of QT vs. black wattle tannin in water.