Abstract
Abstract
This study aimed to determine the effect of different dairy breeds and seasons on reproductive, productive and economic efficiency of dairy farms under Egyptian conditions. This study was carried out through field survey in different regions of Egypt that includes (El Behira, Alexandria and Kafr El-Shaikh) province during the period extended from summer 2012 to winter 2014 on random samples of dairy production sectors. These sectors were Farmers (Fallahy), Private farms (special) and Governmental. The dairy breeds included were Balady (local breed), Holstein-Friesian (exotic breed) and Cross-bred (Balady X Friesian). The reproductive, productive and economic data were collected from cross-sectional and longitudinal and field survey. During the data collection, the researcher was in intimate contact with dairy holders and managers. The dairy farms were visited two times at least, once in summer and the other in winter. The results of our survey concluded that the breed significantly affected (P<0.01) all productive and reproductive traits. Holstein-Friesian cows had highest milk yield, longest lactation period; they maintained their superiority over the other breeds for milk yield in all parities. Despite lower fertility of Holstein-Friesian cows expressed in highest estimate of number of services per conception, days open, calving interval they surpassed all other breeds in the mean milk yield/day of calving interval and average net profit (17273.63 LE/cow/winter season and 4060.96 LE/cow/summer season). Moreover, a significant variation in lactation milk yield in cows calved during different seasons. This could be due to the seasonal influences as well as the type of feed, temperature, humidity and management which varies greatly during different seasons.

Key words: efficiency, reproductive, productive, economic, dairy.