title: Adjustment of pig or litter weights to a 21-day basis in Duroc, Landrace, and crossbred swine.
abstract: A total of 457 Duroc, 137 Landrace, 131 Duroc x Landrace, and 110 three-and four-breed crossbred pigs were used to estimate multiplicative adjustment factors. Sixty-one Duroc, 24 Landrace, 18 Duroc x Landrace, and 16 three- and four-breed crossbred litters were weighed every 3 or 4 d from 13 to 30 d of age. Prediction equations for estimating pig weights from birth to 30 d and from 13 to 30 d of age are presented. Multiplicative adjustment factors for adjusting pig or litter weights to a 21-d basis for pigs or litters that are weighed between 13 and 30 d of age for different breeds and crossbred combinations are listed. Breed, litters within breed, and pigs within litter x breed effects adjusted for age at weighing were different (P less than .01). Quadratic regression coefficients of weight on age of pig from 13 to 30 d of age did not differ (P greater than .10) from zero for Landrace and three- and four-breed crossbred pigs but were significant for Duroc and Duroc x Landrace pigs.
authors.affiliation: Dept. of Anim. Sci., Ohio State University, Columbus 43210.
authors.forename: K M
authors.initials: KM
authors.lastname: Irvin
authors.forename: G A
authors.initials: GA
authors.lastname: Peterson
authors.forename: N D
authors.initials: ND
authors.lastname: Stewart
mesh_terms: D000818:Animals; D001724:Birth Weight; D001835:Body Weight; D001947:Breeding; D003433:Crosses, Genetic; D005260:Female; D016018:Least-Squares Analysis; D008297:Male; D012044:Regression Analysis; D013552:Swine / Q000254:growth & development*