FOOT AND LEG MEASUREMENTS, TOE LESIONS, SOUNDNESS SCORES AND FEEDLOT PERFORMANCE OF CROSSBRED BOARS AS INFLUENCED BY NUTRITION AND AGE

Abstract

The effects of reduced energy intake (ad libitum and 75% of ad libitum) and elevated mineral-vitamin intake (100 and 150% of NAS-NRC daily recommendations) on foot and leg development, incidence and severity of toe lesions, structural soundness scores and feedlot performance were studied in crossbred boars from 35 to 330 days of age (295 days on test). Toe measurements increased over time with little effect of elevated mineral-vitamin levels. At an equal age, ad libitum-fed boars had larger foot measurements; however, weight-correction usually produced larger values for limit-fed boars relative to body weight at 85 and 190 days on test. Incidence and severity of pad and horn lesions were generally not affected by the dietary treatments, but incidence of lesions was generally greatest for the hind outside toe. Limit-fed boars had higher (P < 0.05) soundness scores compared with ad libitum-fed boars, while dietary mineral-vitamin level had no effect. Daily gain of limit-fed boars was 76% that of ad libitum-fed boars with no overall affect on feed per gain ratio. Feedlot performance was similar between mineral-vitamin levels. The findings of this study indicate that elevating mineral and vitamin intake above that recommended by the NAS-NRC (1979) had no effect on toe, foot and leg development or the resulting structural soundness. Restricting feed intake produced boars with slightly larger toes which appeared more structurally sound when examined at an equal weight. Toe lesion scores, however, were similar between energy levels and there appeared to be no relationship between toe lesion scores and structural soundness scores. Key words: Boars, energy intake, minerals, vitamins, toe measurements, toe lesions, soundness