BODY MEASUREMENTS OF PUREBRED AND CROSSBRED SHORTHORN BEEF CALVES FROM BIRTH TO ONE YEAR

Body measurements were recorded at birth, weaning, and one year of age on Shorthorn calves and on crossbred calves out of Shorthorn cows and Angus, Hereford, or Charolais bulls. A total of 254 calves was studied. There were significant breed-of-sire effects in all traits measured. In wither height, body length, and head length, Charolais-sired calves ranked first, followed by calves out of Hereford bulls. Angus-sired calves did not differ from the Shorthorn ones. In heart girth, body depth, and head width, the Shorthorn calves were consistently inferior to the others, while no uniform difference appeared among the three other breeds of sire. Crossbreeding did not modify the relative body measurements, as evidenced by the highly positive between-breed-sire correlations among the traits.

EFFECT OF LIGHT ON THE DEVELOPMENT OF MARKET PIGS AND BREEDING GILTS

A total of 176 Yorkshire pigs (112 barrows and 64 gilts) were raised from weaning to market weight, second estrus or parturition, in a piggery maintained under normal daylight conditions or in darkness. Average daily gain and feed required for gain were not affected by the treatments. There was no significant difference in total backfat or loin eye area between barrows housed in darkness and barrows housed in normal daylight conditions. Gilts raised in darkness reached puberty 11 days earlier than gilts raised in daylight (P < 0.01). Ovulation rate and litter size at birth were not affected by the treatments. Optical enucleation delayed the onset of estrus by 14 days, but had no other detectable effects.