Path Analysis on Effective Factors Affecting 305-D Milk Yield in Simmental Cattle

Abstract

This study was done to evaluate the relationships between some features that affect milk yield in Simmental cattle and was aimed to determine the direct or indirect effects of these features on 305 days milk yield. In this study, the direct and indirect relationships between Simmental cattle's number of lactation (X-1), the age of animal (X-2), calving season (X-3), dry period (X-4), age in the first conception (X-5), age in the first calving (X-6), with 305 d milk yield (Y) was determined by path analysis. With this aim, milk yield records of 341 Simmental cattle were kept during the period of 2006-2009 at Gokhoyuk state farm. According to the results, the relationships between calving season and 305 d milk yield were found to be weak or unimportant in all years (P > 0.05). It was ascertained that the highest relationship between 305 d milk yield and the age of animal was obtained (r=0.712**). Also, there was a very significant positive relationship between the number of lactation and 305 d milk yield (P < 0.01). It was determined that the number of lactation affects 305 d milk yield in the highest level directly by age variable S and indirectly throughout dry period. It was observed that the strongest one of these effects was direct effect. (C) 2011 Friends Science Publishers