SOME ENVIRONMENTAL AND PHYSIOLOGICAL FACTORS AFFECTING FERTILITY RATES IN ARTIFICIALLY INSEMINATED BUNAJI CATTLE HERDS

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Date
1997-06
Authors
HASSAN, MOHAMMED MAI
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Abstract
The objectives of this study were to determine the following: i) The effect of ambient temperature, humidity and body temperature on fertility rates in Buanji cattle, ii) The incidence of luteal phase inseminations in Bunaji cows, iii) The efficiency and significance of some selected methods of estrus detection aids under field conditions. A total of 524 artificial inseminations in 219 Bunaji cattle were carried out for 2 consecutive years to determine the influence of meteorological variables using the temperature-humidity index (THI) model on conception rate (CR). The effect of body temperature on CR was also evaluated by recording rectal and vaginal temperatures at insemination and approximately 12 hours after in 153 non-suckled Bunaji cows. The mean monthly CRs declined from March to May (37.9%, 26.0% and 19.4%, respectively) which were the hottest months with highest mean monthly THI of 7 5.3, 79.4 and 79.7 and highest mean monthly ambient temperature of 35.8°C, 36.1°C and 35.0°C. The CR appreciated thereafter with decreasing THI. Furthermore, mean monthly CR and mean monthly THI were significantly correlated r= -0.828 (P<0.001). Similarly, the individual daily THI a day following insemination was more closely correlated with CR (r= -0.862; P<0.001) than the other days observed. In addition, elevation of rectal temperature (RT) approximately 12 hours post AI altered the CR significantly (P<0.005). The CR dropped sharply from 48.2% to 7.1% as RT increased from 37.1°C - 39.5°C to 39.6°C - 40.2°C. Thermal stress on spermatozoa, ova, process of fertilization, developing embryo and maternal endocrine system was implicated. It was concluded that heat stress and elevation of body temperature may adversely affect the reproductive performance of Bunaji cattle particularly in artificially inseminated herds. Serum progesterone concentrations at insemination measured by Radioimmunoassay (RIA) technique revealed that out of the 122 inseminations conducted in 93 Bunaji cows, 16 (13.1%) were luteal phase inseminations (LPI). The post-service interval spanning 4-51 days were observed in relation to the LPI. The CR of the affected animals was very poor, although most of the cows conceived eventually. Management and "phantom heats" could contribute to the LPI. Seventy-two (72) Bunaji cows were synchronized using double injection of prostaglandin F2 alpha (PGF2& at 13 days interval. The efficiency of some estrus detection aids and ovarian activity were determined by RIA method from blood collected daily starting day of second PGF2& injection until estrus was observed or continuously for 7 days for "non-responders". At the time of the second injection of PGF2& estrus detection aids namely. Tail painting, KaMar heat mount detectors and chin-ball mating device (CMD) were applied on the test cows. The efficiency of the detection aids was compared with visual observation of standing estrus and serum progesterone concentration (SPC). Serum progesterone (P4) levels recorded 73.6% estrus response rate (ERR) while visual observation registered 61.1%. In relation to the total number of estrus periods observed, unaided visual observation, tail painting, KaMar heat mount detector and CMD respectively recorded 52.2%, 82.6%, 82.6% and 7 6.8% detection rates accurately. Visual observation of standing estrus alone did not detect 47.8% of the estrus periods. Furthermore, 30.4%, 30.4% and 24.6% of the estrus shown by tail painting, KaMar detectors and CMD respectively, were not observed by visual observation. Twentyeight (38.9%) cows showed atypical P4 profile. The possible reasons for the irregularities of the P4, the significance and superiority of the heat detection aids, and the magnitude and factors responsible for the false positives and false negatives observed with the detection aids are further highlighted. It was concluded that estrus detection aids improved the efficiency of estrus detection immensely and tail painting is the most suitable and appropriate aid that justified special emphasis for adoption. The overall findings in this study indicate that environmental and physiological parameters are detrimental and can pose serious negative effect on the reproductive performance of artificially inseminated Bunaji cattle. Improvement on the management system and animal husbandry practices particularly during the critical period of the dry season is recommended so as to enhance their reproductive efficiency.
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A Thesis submitted to the Postgraduate School, Ahmadu Bello University in partial fulfilment of the requirements for the degree of MASTER OF SCIENCE IN VETERINARY SURGERY AND MEDICINE (THERIOGENOLOGY) . DEPARTMENT OF VETERINARY SURGERY & MEDICINE FACULTY OF VETERINARY MEDICINE AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA. JUNE 1997
Keywords
ENVIRONMENTAL,, PHYSIOLOGICAL,, FERTILITY RATES,, ARTIFICIALLY,, INSEMINATED,, BUNAJI CATTLE HERDS
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