Application of the Two-Factor Mixed Model in Discrimination Between Buffalo Breeds Regarding Productive and Reproductive Parameters

Proper reproductive performance in buffaloes is the key to dairy economics. Additionally, the reproductive indices are fundamental indicators for the validation of breeding efficiency. A frequent design in animal science is the analysis of data involving repeated observations collected on animals (experimental unit) assigned to different treatments over time. Therefore, this research investigated the effects of four buffalo breed groups and five levels of parity on lactation yield (LY) and lactation length (LL) as productive traits, as well as calving interval (CI), dry period (DP), days open (DO), and days to first breeding (DFB) as reproductive traits, using data from a dairy buffalo farm in Egypt's Ismailia governorate. The results revealed that parity, breed and their interactions showed a highly significant (P < 0.05) effect. The balady breed exhibited the lowest yield features among the breeds (LY=1894.43 kg and LL=233.5 days) with shorter periods up to 13.26 months, 5.14 months, 133.53 days, and 60.78 days for CI, DP, DO, and DFB, respectively. The yield traits of 50% Italian cross-breed buffaloes were the highest (LY=2286.17kg and LL=241.69 days), and the reproductive traits of more than 50% Italian cross-breed buffaloes were the highest (CI=14.05 months, DP=5.75 months, DO=164.45 days, and DFB= 80.48 days). The second parity was the highest across breeds for the productive attributes, but the first parity was the highest for reproductive traits. Buffaloes that produce more milk have poor reproductive performance. Furthermore, animals after the fourth parity performed poorly in both productive and reproductive activities.