Title: Cattle and sheep develop preference for drinking water containing grape seed tannin Authors
|Schauer, C -|
Submitted to: Animal-The International Journal of Animal Biosciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 16, 2013
Publication Date: September 1, 2013
Citation: Kronberg, S.L., Schauer, C.S. 2013. Cattle and sheep develop preference for drinking water containing grape seed tannin. Animal. 7(10):1714-1720. Interpretive Summary: Some types of forage legumes contain natural compounds called condensed tannins. Ingestion of small amounts of condensed tannins by cattle and sheep can benefit animal nutrition and growth and potentially reduce ammonia emissions to the atmosphere. Practical methods are needed, however, for feeding these tannins to livestock. Condensed tannins are soluble in water, thus we reasoned that adding tannins to livestock drinking water may be a practical method. We conducted two trials with cattle and sheep to determine if they would learn to voluntarily drink water containing small amounts of grape seed tannin. We measured liquid intakes and the concentration of blood urea as a measure of nitrogen use efficiency. Both sheep and cattle developed preferences for the tannin solutions over water. Of the tannin solutions offered, both sheep and cattle drank more of the solution with the highest tannin concentration than tap water on more trial days. Ingestion of water with the highest concentration of tannin reduced blood plasma urea concentration in the cattle by 9 to 14%. These results suggested that the cattle and sheep preferred drinking the solutions with the highest concentrations of grape seed tannin because it improved their protein nutrition and reduced ammonia concentrations in the rumen. The results also indicated that a practical approach would be to provide livestock with both tap water and one or two solutions of tannin so that they could adjust their daily intake of tannin depending on the quality and quantity of feedstuffs on offer.
Technical Abstract: Ingestion of small amounts of some types of condensed tannins by ruminant livestock can provide benefits to the animals, their producers and the environment. However, practical methods are needed to make these tannin more available to livestock. Results from previous trials with crude quebracho and black wattle tannin did not indicate that cattle and/or sheep would readily drink water with small amounts of these tannins. Therefore, we conducted preference trials to determine if cattle and sheep would learn to drink water containing small amounts of purified grape seed tannin. After gradual exposure to increasing amounts of this tannin in water during a pre-trial period, five adult ewes and 5 yearling heifers fed alfalfa (Medicago sativa) pellets (19% CP) were offered tap water and several concentrations of grape seed tannin solutions for either 15 (ewe trial) or 20 d (heifer trial). We measured intake of all liquids daily. Concentrations of blood urea were also measured for heifers when they drank only tannin solutions or water. Both ewes and heifers developed preferences for the grape seed tannin solutions over tap water (P < 0.01) although this preference appeared earlier in the trial for the ewes than for the heifers. Both ewes and heifers drank more of the solution with the highest tannin concentration than of tap water on more trial days (P < 0.05). Ingestion of water with the highest concentration of grape seed tannin reduced blood plasma urea concentration in the heifers by 9 to 14% (P = 0.10) and suggested that the cattle and sheep preferred drinking the solutions with the highest concentrations of grape seed tannin because this improved their protein nutrition and/or reduced ammonia concentrations in their rumens.