Effect of kernel processing and particle size of whole-plant corn silage with vitreous endosperm on dairy cow performance

Kernel processing and theoretical length of cut (TLOC) whole-plant corn silage (WPCS) can affect feed intake, digestibility, performance dairy cows. The objective this study was to evaluate for lactating cows the effects kernel TLOC WPCS with vitreous endosperm. treatments were a pull-type forage harvester without processor set 6-mm (PT6) self-propelled (SP6), 12-mm (SP12), 18-mm (SP18). Processing scores 32.1% (PT6), 53.9% 49.0% 40.1% Twenty-four Holstein (139 ± 63 d in milk) blocked assigned six 4 × Latin squares 24-d periods (18 adaptation). Diets formulated contain 48.5% WPCS, 15.5% citrus pulp, 15.0% dry ground corn, 9.5% soybean meal, 6.8% low rumen degradability 1.8% calcium soap palm fatty acids (FA), 1.7% mineral vitamin mix, 1% urea (dry matter basis). Nutrient composition diets (% matter) 16.5% crude protein, 28.9% neutral detergent fiber, 25.4% starch. Three orthogonal contrasts used compare treatments: effect (PT6 vs. SP6) (particle size; SP6 SP12 SP18). Cows fed produced 1.2 kg/d greater milk yield no changes resulting efficiency compared PT6. also more protein (+36 g/d), lactose (+61 total solids (+94 g/d) than mechanism increased components involved fragmentation, starch glucose availability synthesis by mammary gland. However, had lower chewing time tended have levels serum amyloid A Milk similar SP12, but less time. SP18 total-tract digestibility plasma produce SP12. Compared PT6, feeding raised linear odd-chain FA concentration milk. Similarly, reduction these same occurred SP6. proportion C14:1 C16:1 PT6 Lesser trans C18:1 followed C18:0 concentrations observed SP6, which is an indication complete biohydrogenation rumen. Under conditions study, use recommended from hybrids