Factors affecting fertility of dairy cows in Israel.
The objectives of this review are to describe the reproductive parameters monitored in Israeli dairy herds and to evaluate their changes in recent years. Eighty percent of the cows and 70% of the farms use the Israel Cattle Breeders' Association Herdbook and about 50% of them use pedometry systems. Intensive herd medicine is practiced in 80% of the herds by Hachaklait Veterinary Services Ltd. Herd-health reports monitor calving, production and reproduction. Causal analysis explains the effects and interactions of various risk factors involved. The average of 305 days of milk production per cow increased between 2004 and 2008 from 11,200 to 11,903 kg. At the same time the first A.I. conception rate (C.R) dropped from 43.0 to 40.7% and from 35.6 to 30.5% in primiparous cows (PC) and multiparous cows (MC), respectively. The waiting period (WP) was shortened from 106.2 to 93.4 days in PC and from 99.9 to 87.3 days in MC. The undetected heat rate per herd increased from 30.3 to 38.9% and from 33.9 to 43.9% in PC and MC, respectively. The average of days open per herd dropped from 127 to 118.4 and from 127.5 to 120.5 in PC and MC, respectively. The rate of cows open by 150 days in lactation dropped from 42% (+/- 10.2) to 34.2% (+/- 8.1) and 47.1% (+/- 8.8) to 39.5% (+/- 7.1) in PC and MC, respectively. The ratio between summer inseminations and winter inseminations increased from 0.81 to 1.04 from 2000 to 2008. The calving interval (CI) average fluctuated around 424.5 (+/- 2.0) days and 417.5 (+/- 1.7) days in PC and MC, respectively. The average duration of the dry period in 2008 was 60.7 (+/- 4.7, 47-72) days. From 2004 to 2008, the average herd rate of endometritis increased from 38.1 to 46.0% and from 25.5 to 30.1% in PC and MC, respectively. The milk fat to protein ratio in the first test day of lactation has remained steady during the past 5 years. Genetic trends in the breeding values of fertility and milk showed consistent improvement from 2000 to 2006.


CONCLUSIONS
In recent years there has been a small decline in some reproductive parameters, while at the same time others have remained unchanged. The farmer's economical viewpoint and management practices have contributed to the changes.
Galon
Nadav
N
Hachaklait Veterinary Services Ltd, P.O. Box 3039 Caesarea Ind. Park, Israel. chkl343@netvision.net.il
Zeron
Yoel
Y
Ezra
Ephraim
E
D000818:Animals; D001947:Breeding; D002417:Cattle / Q000502:physiology*; D002418:Cattle Diseases / Q000453:epidemiology; D015984:Causality; D003612:Dairying / Q000379:methods*; D005260:Female; D005298:Fertility / Q000502:physiology*; D007247:Infertility, Female / Q000453:epidemiology / Q000662:veterinary; D007557:Israel / Q000453:epidemiology; D007774:Lactation / Q000502:physiology; D008892:Milk / Q000737:chemistry / Q000378:metabolism; D011247:Pregnancy; D018873:Pregnancy Rate / Q000639:trends; D012098:Reproduction / Q000502:physiology