Nutrition during mid to late pregnancy does not affect the birthweight response to mid pregnancy shearing

Abstract

This study was designed to determine whether dam nutrition during mid to latepregnancy influences birthweight responses from pregnancy shearing.Romney-cross ewes were either shorn during mid pregnancy(n = 68) or left unshorn (n= 66). Ewes were offered either a maintenance level of feed (a level ofnutrition that enabled the dam to maintain conceptus-free liveweight) or aed to apparenthomogeneity by using various biochemical fractionation procedures, such assolubilization with Triton X-100, sephadex gel filtration chromatography,concanavalin A–sepharose affinity chromatography anddiethylaminoethyl–cellulose ion-exchange chromatography. The isolatedPPase has a molecular mass of approximately 36 kDa and an isoelectric point of5.95. Sperm surface topography of the enzyme was investigated usingfluorescein isothiocyanate-conjugated antibody of the purified PPase. Theimmunofluorescent studies have demonstrated that the isolated PPase islocalized on the external surface of viable sperm. Immunocytochemical studiesalso revealed a marked topographical alteration of ecto-PPase duringepididymal transit of the male gametes. Immunoreactivity was observed all overthe surface of caput sperm, but was restricted primarily to the anterior tipof the head in the corpus sperm and to the posterior part of the head in caudasperm cells. The maturation-dependent decrease in PPase activity was alsoconfi