DRY MATTER, ETHER EXTRACT, ASH AND MINERAL COMPOSITION OF TOE HORN-WALL FROM CROSSBRED BOARS AS INFLUENCED BY NUTRITION AND AGE

Abstract

The effects of dietary energy level (ad libitum and 75% of ad libitum) and mineral-vitamin intake (100 and 150% of NAS-NRC daily recommendations) on dry matter, ether extract, ash and mineral composition of hard horn-wall taken from front and rear and inside and outside toes were studied in crossbred boars necropsied at 15-day intervals from 85 to 295 days on test starting at 35 days of age. With the exception of Ca and P contents which were higher for restricted-fed boars, restricted energy level and elevated mineral-vitamin intake had little or no effect on horn-wall composition, when expressed on a weight-corrected basis. Horn-wall dry matter, ether extract and Zn content increased over time while ash, P, Mg, Cu, Mn and Fe content decreased with little change in Ca content. Front toes had a lower ether extract, Fe and Mn content than hind toes, and outside toes had a higher content of P, Mg and Mn and a lower content of Cu and Zn than outside toes. Toe size (area and volume) was directly correlated with dry matter, Ca, P, Mg and Zn content, but was inversely correlated with ash, Cu, Fe and Mn content of horn-wall. There appeared to be no relationship between toe size and ether extract content of horn-wall. Horn-wall composition changes occurred over time with only minor effects of nutrition treatments. Although composition of horn-wall varied due to location and size of toe, there appeared to be no relationship between horn-wall composition and toe lesion scores. Key words: Swine, nutrition, toe horn-wall composition, minerals