Effect of Feeding Limited Roughage and a Comparison between Loose and Pelleted Pineapple Hay on Milk Production, Milk Constituents, and Fatty Acid Composition of Milk Fat

Abstract
Twelve lactating Holstein cows were used to evaluate limited roughage feeding and to compare the feeding value of loose and pelleted pineapple hay in terms of milk production, milk constituents, and fatty acid composition of milk fat. An incomplete block switchback design consisting of 6-wk periods (3-wk changeover and 3-wk comparison periods) was used. Treatments were (1) high concentrate-low roughage (10 lb of pineapple bran), (2) medium concentrate-medium roughage (10 lb of pineapple bran and up to 14 lb. of loose pineapple hay), and (3) medium concentrate-medium roughage (10 lb of pineapple bran and up to 14 lb of pelleted pineapple hay). Data from cows on treatments 1,2, and 3, respectively, were: milk production 31.8a, 30.2b, and 29.0c lb; 4% FCM 27.8a, 31.6b and 30.4b lb; butter-fat 3.2a, 4.3b; and 4.3b%; total solids 11.9a, and 12.8b; SNF [solids-not fat] 8.7a, 8.7a, and 8.7a%; protein 3.5a, 3.6a%. Values in the same categories with different superscripts are significantly different when measured by Duncan''s multiple range test. The fatty acid composition of butterfat was determined using gas chromatography. Significant differences between the limited roughage and medium roughage treatments were observed in the C14, C16, C18, C18 =1 and C18 =2 fatty acid portions.