Nineteen Jordanian dairy farms selected by stratified random sample we
re monitored between February 1991 and September 1993 in order (1) to
compare milk yield and reproductive performance of imported Friesian d
airy 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, numb
er of services per conception, rate of repeat breeders, culling rate a
nd days dry. Imported first-calf heifers had significantly more days o
pen, longer lactation length, higher number of services per conception
, higher repeat breeder and culling rates and produced more milk in th
eir first lactation compared with the Jordanian Friesian first-calf he
ifers. In their second lactation, cows imported as pregnant heifers pr
oduced about 802 kg more milk than the Jordanian Friesian cows. Cows i
n herds with more than 59 cows were older on average and had the highe
st 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 stu
dy suggests that farmers should inseminate their cows using semen from
proven sires instead of natural services to improve production and re
productive genetic potential of Jordanian Friesian cows. Also, they sh
ould put more emphasis on through and accurate detection of estrus, es
pecially during the cold weather seasons when cows usually housed, fed
and milked in tie stalls 24 h day-1 with very limited movement. A stu
dy pertaining to the economic analysis should be conducted to enable t
he decision makers to decide whether to continue with the policy of im
porting Friesian breed or to rely upon the locally raised Friesian cow
s.