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Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)
Beschreibungen/Notizen
Nineteen Jordanian dairy farms selected by stratified random sample were monitored between February 1991 and September 1993 in order (1) to compare milk yield and reproductive performance of imported Friesian dairy cows with the Jordanian Friesian dairy cows and (2) to assess the effect of herd size on the reproductive and productive performance of the type of Friesian on milk yield, days open, lactation length, number of services per conception, rate of repeat breeders, culling rate and days dry. Imported first-calf heifers had significantly more days open, longer lactation length, higher number of services per conception, higher repeat breeder and culling rates and produced more milk in their first lactation compared with the Jordanian Friesian first-calf heifers. In their second lactation, cows imported as pregnant heifers produced about 802 kg more milk than the Jordanian Friesian cows. Cows in herds with more than 59 cows were older on average and had the highest annual culling rate. Cows in these herds produced more milk per cow per lactation than cows in herds with 30–59 cows. Results of this study suggests that farmers should inseminate their cows using semen from proven sires instead of natural services to improve production and reproductive genetic potential of Jordanian Friesian cows. Also, they should put more emphasis on thorough and accurate detection of estrus, especially during the cold weather seasons when cows usually housed, fed and milked in tie stalls 24 h day
−1 with very limited movement. A study pertaining to the economic analysis should be conducted to enable the decision makers to decide whether to continue with the policy of importing Friesian breed or to rely upon the locally raised Friesian cows.