Assessment of rearing systems and seasons on nutrient intake and semen freezability in Jamunapari bucks

The present study assessed the semen freezability of Jamunapari bucks reared under 23 rearing systems for 3 consecutive seasons. Bucks (20) were randomly allotted equally to stall feeding (SF) and grazing plus supplementation (GS) systems. Lignin ratio technique was used for nutrients intake determination and indirect indicator method for estimation of total faecal output. Proximate analysis of feeds, forages and faecal samples was done. Semen was collected using artificial vagina twice a week, evaluated and diluted by 2 step method using Tris– eggyolk-citrate-fructose-glycerol diluents having 10% (v/v) egg yolk and 6% (v/v) glycerol. The samples were frozen as per protocol developed at this Institute. The data were analyzed by standard statistical method. The overall dry matter intake, digestible crude protein intake and metabolizable energy intake of GS bucks were significantly higher than the SF bucks. The bucks consumed significantly higher nutrients in winter followed by summer and rainy season. The initial progressive motility varied significantly between rearing systems and among seasons. The overall pre-freeze and post-thaw progressive motility was similar between rearing systems and seasons. Post-thaw progressive motility was significantly lower in summer than the other seasons studied.