الفهرس 
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Abstract
The current study was conductedon (693) Holstein dairy cows to investigatethe incidence of metritis and endometritis in dairy farms during the post-partum period, moreover, to determine the collective impact of metritis and endometritis in dairy farms on reproductive performance and milk yield.
The lactating Holstein cows included in the current study were between 2 and 10 years. Cows generally were fed according to (National Research Council, 2001).
The cows were routinely vaccinated against all infectious diseases according to programs of vaccination; FMD, Lumpy skin disease, Rift Valley Fever, infectious bovine rhinotracheitis (IBR), bovine viral diarrhea (BVD), parainfluenza3 (PI3), bovine respiratory syncytial virus (BRSV), Brucellosis (RB-51®) and Clostridia species.
All cows were milked three times a day. All cows appeared healthy and had body condition scores between 2.5 and 5 (scale 1 to5).
Cows were examined immediately postpartum. Data at the time of examination including parity, calving history and incidence of postparturient disorders were recorded. Estrus detection was performed by the herd manager and the staff of the farm by visual observation.
All herds used artificial insemination (AI) exclusively after a voluntary waiting period of approximately 50 days postpartum (range 45 to 60 days).
The obtained results showed that metritis and lameness represented the most prevalent disorders among primiparous cows of 19 and 18%, respectively. While primiparous cows with both subclinical and clinical mastitis and those with metritis and endometritis represented the lowest prevalence (4% for both).Prevalence of metritis and RFM accounted for 25% of the overall prevalence of infertility problems among primiparous cows.
In pluriparous cows, postpartum lameness followed by clinical mastitis and subclinical mastitis were the highest recorded problems. As compared to primiparous herd-mates, prevalence of metritis and RFM accounted only for 12% of the total infertility problems in pluriparous cows.
No clear effects of infertility problems studied in our work were observed on peak milk production in primiparous cows. Peak milk fluctuated between 40.18 Kg in cows with subclinical mastitis and 43.71 Kg in cows with early endometritis.Primiparous cows suffering from late endometritis peaked earlier (48.78 days) than other cows including control cows (66.67 days). Interestingly, cows with early endometritis or with metritis and endometritis reached peak production at delayed DIM (67.29 and 67 days, respectively).
Pluriparous cows with RFM expressed the most delayed peak production day (53.6 Kg) when compared to other infertility problems. Nearly all pluriparous cows peaked above 50 kg milk except for cows with RFM (48 Kg), cows with late endometritis (47.91 Kg) and those metritis and endometritis (49.19 Kg).
It was clear that endometritis possessed the severest negative effects on postpartum reproductive performance of studied cows, followed by mastitis, compared to other diseases and to normal cows. Moreover, the impact of these diseases was higher in primiparous cows, compared to their pluriparous herd-mates.
Advancing parity in the present work was associated with a lower incidence of RFM in the studied Holstein cows.
Incidence of endometritis was increased with advancing parity in the current study varying from 14.04% for primiparous cows to 21.88% for 4th lactation cows.
Metritis in the present work did not show any association with parity in Holstein cows (R2=0.006).
Moreover, the impact of endometritis was higher in primiparous cows, compared to their pluriparous herd-mates. Days to first estrus tended (P=0.06) to be increased in primiparous cows suffering from endometritis (89.19±12.12 days) compared to normal cows (59.45±3.30 days) or those suffering from metritis (65.37±4.92 days).
While in pluriparous cows, the negative effects of endometritis did not show any tendency for prolonged days to first estrus, when compared to normal cows. Endometritis had significantly (P<0.01) negative impacts on postpartum cyclicity in primiparous cows (89.19±12.12 days), compared to 56.32±3.15 days in pluriparous cows.
Endometritis, significantly negatively (P<0.05) impacted days to first AI in both primiparous cows (105.63±12.95 days, compared to 65.97±2.63 days for normal cows and pluriparous cows (76.19±3.64 days), compared to 66.61±1.44, days for normal cows.
Advancing parity was associated with significantly (P<0.05) higher days open for cows suffering from endometritis only.