Early lactation responses of Holstein cows fed a rumen-inert fat prepartum, postpartum, or both.
Primiparous (n = 22) and multiparous (n = 41) cows were randomly assigned by calving date and parity to one of four dietary sequences of supplemental fat from 14 d prepartum to 151 d postpartum. Partially hydrogenated tallow was added to diets at 0% prepartum and postpartum (control); 1% prepartum and 2% postpartum; 0% prepartum and 2% postpartum; and 0% prepartum, 0% from 1 to 34 d postpartum, and 2% from 35 to 151 d postpartum. Inclusion of partially hydrogenated tallow did not influence yields of milk or 3.5% FCM, milk composition, or DMI during the first 151 d postpartum. During the first 35 d postpartum, cows receiving partially hydrogenated tallow starting at parturition yielded milk with a higher fat content than those receiving fat prepartum and postpartum. Addition of partially hydrogenated tallow to diets starting 35 d postpartum resulted in cows being more persistent in yields of milk and 3.5% FCM from 60 to 151 d postpartum. Reproduction parameters measured were unaffected by time of fat addition to diets. Our data suggest that delaying the addition of partially hydrogenated tallow to diets until 35 d postpartum may improve the persistency of lactation.
Salfer
J A
JA
Department of Animal Science, University of Minnesota, St. Paul 55108, USA.
Linn
J G
JG
Otterby
D E
DE
Hansen
W P
WP
Johnson
D G
DG
D000818:Animals; D001835:Body Weight; D002417:Cattle / Q000097:blood / Q000502:physiology*; D003612:Dairying / Q000379:methods; D004041:Dietary Fats / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D007774:Lactation / Q000502:physiology*; D008892:Milk / Q000737:chemistry; D010298:Parity / Q000502:physiology; D049590:Postpartum Period / Q000502:physiology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D012098:Reproduction / Q000502:physiology; D013223:Statistics as Topic; D013997:Time Factors
D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified