title: The feeding value of extruded corn grain in a corn silage-based ration for high-producing Holstein cows and heifers during mid lactation.
abstract: The objective of this study was to investigate the feeding value of extruded corn in a corn silage-based ration for high-producing Holstein cows during mid lactation. Sixteen multiparous and 8 primiparous Holstein cows (106 +/- 49.7 d in milk; 43.7 +/- 5.27 kg of milk/d) were paired based on parity, days in milk, milk production, and body condition score and assigned to 1 of 2 dietary treatments in a randomized block design for 10 wk including a 2-wk adaptation period. Cows were fed a total mixed ration and milked 3 times per day. Diets contained 44% forage (3:1; corn silage:grass silage), 44.7% grain, and either extruded corn (EXC) or finely ground corn (FGC) at 11.3% of ration dry matter. No significant differences were detected in dry matter intake, milk protein yields, fat-corrected milk yields, or body condition score between cows fed FGC and cows fed EXC. Multiparous cows fed EXC produced more milk during wk 3 through 8 with a reduced milk fat content compared with multiparous cows fed FGC. Milk protein content was greater for primiparous cows fed EXC during wk 5 through 8 compared with primiparous cows fed the FGC ration. The major effect of feeding 2.7 kg/d of EXC compared with FGC was an increase in milk production and a reduction in milk fat content for multiparous cows, and an increase in milk protein content for primiparous cows.
authors.affiliation: Department of Animal Science, University of Connecticut, Storrs 06269-4040, USA.
authors.forename: P
authors.initials: P
authors.lastname: Rezamand
authors.forename: S M
authors.initials: SM
authors.lastname: Andrew
authors.forename: T A
authors.initials: TA
authors.lastname: Hoagland
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001824:Body Constitution / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D002417:Cattle / Q000378:metabolism*; D003612:Dairying; D004032:Diet / Q000662:veterinary*; D004435:Eating / Q000502:physiology; D005223:Fats / Q000032:analysis; D005260:Female; D007774:Lactation / Q000502:physiology*; D008892:Milk / Q000737:chemistry; D008894:Milk Proteins / Q000032:analysis; D010298:Parity / Q000502:physiology*; D011247:Pregnancy; D011897:Random Allocation; D012820:Silage; D013997:Time Factors; D014508:Urea / Q000032:analysis; D003313:Zea mays / Q000378:metabolism*
chemical_list: D005223:Fats; D008894:Milk Proteins; D014508:Urea