Gene frequencies were estimated in a sample of Baladi cattle for milk proteins, blood proteins and blood groups. Gene frequency estimates of Bos taurus, Bos indicus and Sanga breeds were assembled from the literature. The gene frequencies were utilized for estimating the genetic distance between the breeds and breed groups. The Egyptian Baladi cattle appeared to be closer to Bos taurus breeds than to the Sanga. They are far removed from Zebus.

The introduction of large numbers of European dairy cattle in the Arab world in the last decade, and up till now, aims at increasing the animal protein output of these countries to face the animal-protein gap in human diet. Available reports and research on the performance of these cattle under the adverse conditions in their new habitat, feed, health and management beside the hot summer weather, show clearly that the productivity and reproductivity of these exotic breeds deteriorate, that is when compared to the European standards of performance (see AOAD 1983, for a comprehensive review of cattle production in the Arab world). The stressful environment may arrest the full expression of the exotic genotypes. Also, animals of relatively high milk yield, that is higher than a certain limit dictated or tolerated by the environment, may be rejected earlier, and consequently will have shorter longevity compared to those of lower production. This would imply developing a negative relationship between milk yield of the earlier lactations and both longevity and reproductive efficiency. Negative correlations were reported by several investigators (CAR-MAN 1955; EVERETT, ARMSTRONG and BOYD 1960;SPADLING, EVERETT and FOOTE 1975) between lactation yield and reproductive efficiency. GILL and ALLAIRE (1976) found that each increment in yield of first lactation above a certain level leads to negative differences in herdlife.In this work comparisons are made in each lactation between the means of milk production, lactation length and average daily milk yield, of cows staying on the farm to produce the next record and of those discarded after completing that particular lactation. If no selection pressure is exerted on milk yield and no relationship exists between milk yield and herdlife time, no differences between trait means are expected. Records on Friesian, Jersey, Pinzgauer and buffalo are utilized. Data and analysisThe data utilized in this work comprise four sets of records including information on actual milk yield and the number of days in milk (from which a third trait was calculated: the average daily milk yield):1. The Frzesiun recoids: Records commencing within the period from 1975 till April 1982 inclusive were collected on the Friesian herds of three Libyan farms (in Tripoli, Benghazi and Sebha). A detailed description of these data will be published soon by two of the present authors (M. A. M. and A. A. N.) and their coworkers. The total of 3318 records used was distributed among the first five lactations (in their respective order) as follows: 1511, 823, 457,322 and 205. Sebha farm did not contribute to the records of the fifth lactation. U.S.

No abstract

The Baladi cattle in Egypt are kept mainly for draft work and meat production; their milk yield is really very humble. As such, this breed fits the needs of the farmer, and performs comparatively well under the standards of feeding and hushandry prevalent in the Egyptian village.With the introduction of mechanization, however, animals will be exempted from most of the draft work and the purpose of keeping cattle is thus expected to change towards milk and beef production. Baladi cattle would not compete with the exotic beef or dairy breeds, and most of their present population have to be changed to serve the new goals. The treatment of high milk producers would not be an easy job for a farmer used to a cow ofvery low milk production or to a buffalo of an average milk yield of less than 1.5 tons/lactation. A transition period to acquire the skills to the proper treatment of high milk producers is needed. Crossbreeding and grading up with dairy breeds would be an obvious way, whereby the farmer's skills could be graded up in time with the increase of exotic blood in his cattle. This work presents the results of grading up Baladi cattle in Egypt with Friesian on milk production of the first two lactations. Material and methodsData were collected from the Serw Farm belonging to the Ministry of Agriculture. The farm is situated north-east of the Nile Delta. Records on the 305-days milk yield of the first (999 records) and the second (784 records) lactations were obtained beside age at first and second calving. These data represent Baladi cattle (Damietta strain), pure Friesians and the first five Friesian grades (%, %, %, I%&, '%I). Grades of higher orders were all included in the % group. The available data covered the period from 1940 till 1971, and were classified, for analysis, in groups each of two years, except the first group which included theobservations till 1944 in the first lactation and till 1948 in the second lactation, thus having 15 year groups in the first case and 13 in the second. Table A presents the number of first lactations distributed by genotype and year. &kl = P + g, + s, + yk + e,,kl, where X,,kl is the milk yield of the I& animal, in the k& year group in the j& season of calving of the i& genotype, The model used for milk yield reads: t deceased. U.S.