Veterinary Obestrics and Gynaecology

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Browsing Veterinary Obestrics and Gynaecology by Author "Fekadu Regassa"

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    Association of Subclinical Mastitis and Lameness with Reproductive Performance and Subclinical Endometritis in Zebu X Friesian Crossbred Dairy Cows In And Around Jimma Town Dairy Farms, Ethiopia
    (Addis Ababa University, 2023) Nuraddis Ibrahim; Fekadu Regassa
    A longitudinal observational study was conducted to assess the association of subclinical mastitis and lameness with reproductive performance and subclinical endometritis in crossbred dairy cows. The California Mastitis Test and cytobrush technique were used to screen for subclinical mastitis and subclinical endometritis, respectively. Samples positive for subclinical mastitis were subjected to bacteriological analysis. Lameness in cows was also assessed using a 5-point locomotion scoring system. Analysis of progesterone and cortisol concentrations in blood serum of cows was performed using electrochemiluminescence immunoassay “ECLIA”. A total of 84 clinically healthy cows were tested for subclinical mastitis using the California Mastitis Test. The prevalence of subclinical mastitis at cow level was 51.2% (43/84). The prevalence of subclinical mastitis in 108 lame cows was 53.7% (58 of 108). Based on the results, the 192 cows according to the study were divided into the following four groups: Group I (n=43) cows with subclinical mastitis, Group II (n=50) are lame cows, Group III (n=58) lame cows with subclinical mastitis and Group IV (n=41) healthy cows (control group). Lame cattle are also classified as no lameness, mild lameness, moderate lameness, lameness, and severe lameness. Mean number of days from calving to first mating interval was highly significantly longest in lame cows with subclinical mastitis (122.71±28.6) than for lame cows (120.98±31.3), subclinical mastitis cows (120.51±24.5) and healthy cows (85.15±28.3) (P<0.05). Mean number of services per conception was significantly highest in lame cows with subclinical mastitis (3.66±1.31) than lame cows (3±1.6), subclinical mastitis cows (2.51±0.83) and healthy cows (1.59±0.81) (P<0.05). Cows clinically lame had a longest calving to first service interval when compared with cows which were never lame and those mildly lame. The difference was significant (P<0.05). Lowest conception and pregnancy rates at first services were observed in lame cows with subclinical mastitis. Cows that were clinically lame had a lowest conception rate at first services than cows that were never lame and mildly lame, although the difference was not statistically significant (P>0.05). Clinically lame cows had a lowest pregnancy rate at first services than cows that were never lame and mildly lame (P<0.05). Risk factors analysis revealed that prevalence of subclinical mastitis, lameness and in lame cows with subclinical mastitis significantly differed with the parity and body condition score (P<0.05). The present study revealed that subclinical mastitis and lameness were significantly and directly associated with subclinical endometritis (P<0.05). Progesterone concentrations highly decreased in lame cows with subclinical mastitis than in subclinical mastitis and lameness alone while the cortisol concentrations also highly increased in lame cows with subclinical mastitis. The major bacterial isolate was Staphylococcus aureus. In conclusion these results provide further evidence that combined occurrence of subclinical mastitis and lameness inflict harmful effects on fertility and hormonal profiles of dairy cows than those diagnosed with mastitis and lameness alone, emphasizing the relevance of mastitis and lameness control programs in dairy farms.
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    Bovine Viral Diarrhea Virus (BVDV) Exposure in Dairy Cattle in Southern and Central Ethiopia and Potential Association with Reproductive Performance
    (Addis Ababa University, 2022) Kassaye Aragaw; Fekadu Regassa
    Bovine viral diarrhea virus (BVDV) is an important viral pathogen of cattle with a worldwide distribution. Although infection with the virus is usually subclinical, it may cause wideranging clinical conditions in cattle. Its main economic significance results from its effect on reproductive performance of cattle. It causes embryonic mortality and absorption, abortion, stillbirth, fetal malformation and birth of weak calves depending on stage of pregnancy during infection. In cetain outbreaks it may cause severe morbidity and mortality in susceptible herds depending on the strain of the virus. Despite the economic importance of the virus in almost every major cattle producing countries of the world only few studies have so far been conducted in Ethiopia. Those few works were also mostly limited to serological studies in limited geographic areas. There is lack of reports regarding occurrence of active disease or outbreaks associating infection with clinical conditions and losses. There is also so far no published work on the genotype of the virus prevalent in the country. Therefore this study was designed with aims to estimate the seroprevalence, identify associated risk factors and assess association of BVDV serostatus with reproductive wastage in dairy cows in Ethiopia. The study also attempted to detect and characterize BVDV nucleic acid in samples collected from bovine abortions and sera collected from selected animals. Accordingly, sera were collected from 954 randomly selected cattle from 98 dairy herds in southern and central Ethiopia. These sera samples were tested for BVDV antibodies using a commercial ELISA. Fetal tissue samples and placenta from 30 bovine abortions and sera from 26 selected cattle were also collected for detection of BVDV nucleic acid using reverse transcription (RT)-PCR. Among screened sera samples 20.9% (95%CI, 18.4, 23.6) were tested positive to BVDV antibodies. The herd prevalence was 50% (95%CI, 40.1, 59.9) and the intra-herd prevalence ranged between 2.6% and 100% (mean = 31.4%) in positive herds. Geographic region, herd size and animal arrangement in the farm had significant association with serostatus (p <0.05). Cattle from southern Ethiopia and herds of large size had 2.8 (95%CI; 1.9, 4.2) and 2.6 (95%CI; 1.5, 4.6) times higher odds of being seropositive compared to their counterparts, respectively. Serostatus to BVDV was associated with history of anestrus, repeat breeding (RB), mastitis and extended calving interval (CI) (p <0.05). Animals with history of extended CI and mastitis were 1.7 (95%CI; 1.0, 2.7) and 2.2 (95%CI; 1.5, 3.2) times more likely to be seropositive compared with those with normal CI and no history of mastitis, respectively. On the other hand, animals with history of anestrus and RB were less likely to be seropositive to BVDV compared to cattle with no such history. All samples tested with RT-PCR were negative for BVDV nucleic acid. Our study highlights the association of BVDV infection with some important reproductive performance traits and potential risk factors. The study also demonstrated high occurrence of reproductive health problems in dairy cattle in Ethiopia and that the reproductive performance of dairy cattle in the study herds is suboptimal.
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    Subclinical Endometritis and its Effect on Reproductive Performance of Crossbred Dairy Cows in Debre Zeit
    (2007-06) Bacah Belachew; Fekadu Regassa
    In this study 59 postpartum crossbred dairy cows were selected from three different farming scales (smallholders, medium sized and large scale dairy farms). Each cow had a normal parturition and had no abnormal uterine discharge by vaginoscopy or no abnormality in rectal palpation. Then the cows were examined for subclinical endometritis by examination of endometrial lavage sample for the presence of neutrophils at the 4th and 8th weeks postpartum. The prevalence of cytologically diagnosed subclinical endometritis was 47.5% at the 4th and 30.5% at the 8th weeks of postpartum. In the three farming scales the prevalence of subclinical endometritis was 64.7% in small holders, 40.7% in medium sized and 40.0% in large-scale farms at the 4th week of postpartum (P = 0.240). While prevalence of 41.2%, 26.7% and 25.9% was recorded at the 8th week of postpartum (P = 0.526) in small, medium and large scale dairy farms respectively. Parity did not influence the prevalence of subclinical endometritis at the 4th week of postpartum (P = 0.492). Cytologically diagnosed subclinical endometritis was greatly associated with impaired reproductive performance. Cows that had subclinical endometritis at the 4th week postpartum required a mean of 2.4 services per conception compared to 1.7 services per conception for normal cows (P = 0.000) where as at the 8th week postpartum 2.7 services per conception were required for cows with subclinical endometritis, compared to 1.7 for normal cows (P = 0.001). For cows with subclinical endometritis at the 4th weeks postpartum the median calving to first service interval were 96 days and 80 days for normal cows (P = 0.000) while at the 8th week postpartum it was100 days for cows with subclinical endometritis and 82 days for normal cows. For cows with subclinical endometritis at the 4th weeks postpartum the median days open were 174 and 152 for normal cows (P =0.001) while at the 8th week of postpartum it was 178 for cows with subclinical endometritis and 155 days for cows without subclinical endometritis (P = 0.000). Also, there was a significant difference in first service conception rate between cows with and without subclinical endometritis at the 8th week of postpartum (3.4 versus 27.1%; P < 0.05). From those cows diagnosed negative for subclinical endometritis at the 8th week postpartum Proportionally 51% of cows confirmed to be pregnant with in 180 days, whereas from those positive cows for subclinical endometritis only 2% confirmed to be pregnant. The proportion of cows confirmed to be pregnant with in 180 days were 41 and 12% for normal cows and cows with subclinical endometritis at the 4th week of postpartum respectively. These results also indicated that there was an association between subclinical mastitis and IX subclinical endometritis at the 4th (P = 0.012) and 8th (P = 0.031) week of postpartum. From the follow up findings, it was observed that risk factors like poor body condition scores at the 4th week of postpartum had an association with subclinical endometritis (P = 0.017). Dairy cows with no regular exercise had a higher prevalence of subclinical endometritis than those exercising regularly (53.6 versus 46.4%; P = 0.026). In conclusion subclinical endometritis diagnosed by endometrial cytology in the postpartum period had a detrimental effect on current reproductive performance.