Effects of Chestnut Hydrolysable Tannin on Intake, Digestibility, Rumen Fermentation, Milk Production and Somatic Cell Count in Crossbred Dairy Cows

SIMPLE SUMMARY: Mastitis is a disease that has a significant impact on the global dairy industry, including productivity, quality and farmer income. There are several methods for preventing mastitis. The use of secondary substances (hydrolysable tannins) to prevent the development of mastitis in dairy cows is one example. Hydrolysable tannins have been shown to reduce the bacteria that cause mastitis in the udder. A previous study report discovered that hydrolysable tannins could eliminate both Gram-positive and Gram-negative bacteria that cause mastitis. The aim of this study was to determine how chestnut hydrolysable tannins (CHT) supplemented at levels of 0, 3.15, 6.30 and 9.45 g/day in milking cows affected intake, digestibility, rumen fermentation, and milk yield and quality. As result, CHT supplementation was found to have a promising effect on nutrient apparent digestibility and rumen fermentation. Furthermore, the somatic cell count (SCC) in milk was reduced, indicating lower bacterial contamination in milk. ABSTRACT: This study was conducted to determine the effects of chestnut hydrolysable tannin (CHT) on intake, digestibility, rumen fermentation, milk yield and somatic cell count in crossbred dairy cows (>75% Holstein Friesian). Four crossbred dairy cows (467.6 ± 35.2 kg BW) were assigned to be supplemented with one of four levels of CHT according to a 4 × 4 Latin square design. Dietary treatments included the control (without CHT supplementation) and CHT treatments that consisted of supplementation with 3.15, 6.30 and 9.45 g CHT/day. Rice straw was given ad libitum. The results showed that increasing levels of CHT tended to quadratically decrease rice straw intake (p = 0.06). However, total dry matter intake (DMI) and other nutrients were not different (p > 0.05) among the dietary treatments. The apparent digestibility of DM, organic matter (OM) and crude protein (CP) in cows with CHT treatments were higher (p < 0.05) than those of control cows. Milk yield and milk composition were not different (p > 0.05) among treatments. Lactose yield tended to increase linearly (p = 0.09) as CHT supplementation increased. Ruminal pH and ammonia nitrogen (NH(3)-N) were not different (p > 0.05), but total volatile fatty acids (VFAs) increased linearly (p < 0.05) as CHT levels increased. The somatic cell count (SCC) and somatic cell score (SCS) in the CHT treatments were different (p < 0.01) than those in the control treatment. In conclusion, it appears that CHT supplementation improved feed utilization and influenced SCC in crossbred dairy cows. Long-term research is needed to confirm the benefit of CHT supplementation.