INFLUENCE OF BREED OF SIRE, DIETARY INTAKE AND HOUSING FACILITIES ON THE ATTAINMENT OF PUBERTY IN CROSSBRED GILTS

Abstract

The role of diet intake and type of confinement pen in the stimulation of puberty was determined with 483 gilts from a Landrace (L) × Yorkshire (Y) rotational cross over 4 yr. At 160 d of age, gilts were housed either in stalls (S) or groups (G) of eight per pen. They were fed a diet intake level to provide approximately 0.4 kg gain d−1 for the duration of the experiment (C) or 0.0 kg d−1 for the first 2 wk (R) and then as for C. Gilts were checked for estrus once daily with vasectomized boars. AU S gilts had 30 min d−1 of in-pen exposure to mature boars, while G gilts had constant pen line exposure to mature boars. Over the 8-wk period 73.5% of the gilts attained puberty. Diet intake restriction and group penning had similar effects on the mean interval to puberty, with C and R gilts averaging 13.6 ± 1.0 and 17.4 ± 1.0 d (P < 0.01), and S and G gilts averaging 12.3 ± 0.9 and 18.7 ± 1.1 d (P < 0.01). Both the Rand G treatments resulted in a delay in the attainment of puberty as compared to S-penned C gilts. This difference was apparent within 3 d. The delay in puberty associated with diet intake restriction was found only in S-penned gilts and was eliminated 10 d after the R gilts were placed on the C level of diet intake. The group penning delay in attaining puberty was evident for 31 d in Y-sired gilts and to the end of the experiment in L-sired gilts. In L-sired gilts 85.3 and 55.6% of the S and G gilts, respectively, attained puberty (P < 0.05) as compared to 74.6 and 76.9% of the Y-sired gilts. Thus, the ability of the gilt to attain puberty in response to boar exposure is dependent on the breed of gilt, diet intake and pen type, with stalls and an adequate growth rate required for the greatest response. Key words: Gilts, puberty, breed, diet intake, pen type