title: Characteristics of digestion of linted and lint-free cottonseed in diets for feedlot cattle.
abstract: Eight Holstein steers (439 kg) with "T" cannulas in the rumen and proximal duodenum were used to evaluate the characteristics of digestion of Pima cottonseed. Treatments consisted of a basal growing-finishing diet containing (DM basis) 1) 15% tapioca, 2) 15% whole linted cottonseed (Delta Pine 61, DP); 3) 15% whole lint-free cottonseed (Pima, PW), and 4) 15% ground Pima cottonseed (PG). Substitution of tapioca with cottonseed decreased (P < .05) ruminal and total tract digestion of OM (10.8 and 3.5%, respectively). Net ruminal microbial N synthesis was also lower (20.5%, P < .10) with cottonseed supplementation. The greater reductions occurred with DP and PG. Characteristics of ruminal and total tract digestion of OM and N were similar for DP and PG. Grinding Pima cottonseed increased ruminal digestion of OM (13%; P < .05) and feed N (18.1%; P < .10). Ruminal digestibility of N in DP, PW, and PG averaged 50.0, 49.4, and 59.3%, respectively. Postruminal digestion of lipid was similar (P > .10) across cottonseed treatments, averaging 76.9%. The comparative DE value of DP, PW, and PG were 4.13, 3.20, and 3.80 Mcal/kg, respectively. It is concluded that the energy value of lint-free Pima cottonseed is similar to that of linted varieties provided that it is ground before feeding. However, grinding will increase ruminal N degradability 20%. Furthermore, depending on the level of incorporation in the diet, grinding Pima cottonseed may decrease ruminal microbial growth and net ruminal protein efficiency.
authors.affiliation: Animal Science Department, Imperial Valley Agricultural Center, University of California, El Centro 92243, USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Zinn
mesh_terms: D000821:Animal Feed / Q000592:standards; D000818:Animals; D002417:Cattle / Q000254:growth & development / Q000502:physiology*; D003369:Cottonseed Oil / Q000378:metabolism*; D004032:Diet / Q000592:standards*; D004063:Digestion / Q000502:physiology*; D004386:Duodenum / Q000502:physiology; D005511:Food Handling; D008297:Male; D011897:Random Allocation; D012417:Rumen / Q000502:physiology
chemical_list: D003369:Cottonseed Oil