Influence of penning type and feeding level on sexual behavior and feet and leg soundness in boars.

Ninety-six Yorkshire males at 28 d of age were placed on a pre-test feeding regimen (22% CP) of either ad libitum (A) access to feed or a restricted (R, 85% of A) diet. All pigs were housed in groups of four until approximately 30 kg body weight. The boars were then placed under test and assigned to a group pen (GP) containing eight boards or to individual pens (IP) and fed a 16% CP diet at A or R levels. Feeding types during pre-test and test phases were, therefore, ad libitum followed by ad libitum (AA), ad libitum: restricted (AR), restricted: ad libitum (RA), and restricted: restricted (RR) for each of the two (IP and GP) housing types. All boars were weighed every 2 wk to determine the feeding level and ADG. The pen floors were partly slatted with water nipples in the slatted areas. Areas available for each board were 1.63 and 2.15 m2 in IP and GP, respectively. Sexual behavior, semen characteristics, and feet and leg scores were recorded between 150 and 240 d of age. The IP boards required longer (P < .05) contact with receptive gilts before mating, made more (P < .01) ano-genital sniffings, and attempted more (P < .10) incorrect mounts than GP boars. The GP boards had a higher (P < .01) mating score, younger (P < .001) age at completion of the mating test, and lower (P < .01) total sperm count and sperm concentration (P < .001) than IP boars. The AA boards exhibited less (P < .10) chomping and salivation than boars on other feeding regimens.(ABSTRACT TRUNCATED AT 250 WORDS)