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