title: Relationship of milk production, milk expected progeny difference, and calf weaning weight in angus and simmental cow-calf pairs.
abstract: Milk EPD, used to predict the milk production potential of a parent's daughters, have been reported by all major cattle breed associations. Our objectives were to determine the relationship of milk EPD of a dam to actual milk production (both fluid and components) and offspring weaning weight. Angus (AN; n = 114) and Simmental (SM; n = 82) cows were machine-milked at approximately 60, 104, and 196 d postpartum after overnight calf removal. In addition, one herd of AN was also milked at approximately 35 and 145 d postpartum. A lactation curve was fitted to these measurements to estimate total milk production during lactation. Simple correlations between 205-d total milk yields (TMY) and adjusted 205-d calf weaning weight (WW) were .30 (P < .001) and .47 (P < .001) for AN and SM, respectively. Furthermore, milk EPD was positively correlated to adjusted WW (r = .38 P < .001; r = .39, P < .001) and TMY (r = .32, P < .001; r = .44, P < .001) for AN and SM cows, respectively. A 1-kg change in TMY changed WW by .014 +/- .006 kg (P < .001) in AN and by .032 +/- .009 kg (P < .001) in SM. A 1-kg change in milk EPD resulted in a 4.85 +/- 1.14 kg change in WW (P < .001) in AN and a 3.74 +/- 1.73 kg (P < .05) change in SM. Corresponding changes in TMY were 42.1 +/- 16.6 kg (P < .01) and 69.3 +/- 16.0 kg (P < .001) for AN and SM, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Animal Science and Industry, Kansas State University, Manhattan 66502.
authors.forename: T T
authors.initials: TT
authors.lastname: Marston
authors.forename: D D
authors.initials: DD
authors.lastname: Simms
authors.forename: R R
authors.initials: RR
authors.lastname: Schalles
authors.forename: K O
authors.initials: KO
authors.lastname: Zoellner
authors.forename: L C
authors.initials: LC
authors.lastname: Martin
authors.forename: G M
authors.initials: GM
authors.lastname: Fink
mesh_terms: D000818:Animals; D000833:Animals, Suckling / Q000254:growth & development*; D001835:Body Weight; D001947:Breeding; D002417:Cattle / Q000254:growth & development / Q000502:physiology*; D005260:Female; D007774:Lactation / Q000502:physiology*; D016018:Least-Squares Analysis; D008892:Milk / Q000737:chemistry / Q000378:metabolism; D009752:Nutritional Status; D014886:Weaning; D015430:Weight Gain