Dynamics of harvesting and feeding Cynodon hybrid Tifton 85 hay of varying maturities to wether kids

Cultivar Tifton 85 bermudagrass [Cynodon dactylon (L.) Pers. x Cynodon transvaalensis Burtt Davy] hay is widely used as a feed for goats in warmer regions of North America. A pen trial compared Tifton 85, harvested as hay at 14, 21, 28 and 35 days regrowth, as the sole feed for Boer by Spanish cross wethers during two consecutive years. Mechanically harvested hay was also compared to hand-clipped samples at these maturities to measure yield, harvest loss, and nutritive value differences. Clipped plant yield for 14-day regrowth was 125% greater (P < 0.05) while 28-clay regrowth was 41% greater (P < 0.05) compared to mechanically harvested hay at the same maturities. Leaf and stem ratios differed (P > 0.05) depending on harvest method and leaf CP concentrations declined (P < 0.05) as plants matured. Wethers left 36% of 21-day hay compared (P < 0.05) to 45% 0135-day hay and selected more against stem as hay matured. In less mature hay, kids selected (P < 0.05) for nutritive value among stems on offer but avoided all stems equally (P > 0.05) in more mature hay, whereas no differences were measured in hay and leftover leaf nutritive values. Wethers gained over 80 g/day on 14- and 21-day hay, nearly double (P < 0.05) the rate of gain for animals on 28- and 35-day hay. Taken as a whole, results indicate that Tifton 85 hay harvested at 21-day regrowth combines the most efficient and productive maturity for feeding growing wethers despite 44% less (P < 0.05) yield than 28-day hay. (C) 2010 Elsevier B.V. All rights reserved.