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Effects of rectal and ambient temperatures and humidity on conception rates
THERIOGENOLOGY EFFECTS OF RECTAL AND AMBIENT TEMPE~TU~S
AND ~IDITY
ON CONCEPTION RATES
A. Y. Zakari,a E.C.I. Molokwu
b
and D. I. K. OsoriC
Ahmadu Be110 University, Zaria, Nigeria, "National Animal Production Research Institute. b Department of Veterinary Physiology & Pharmacology. % epartment of Veterinary.Surgery& Medicine. Received for publication: March 26, 1981 accepted: July 2, 1981 ABSTRACT One hundred and thirteen inseminationswere performed for which rectal temperatureswere taken at the time of inseminations. Climatological factors were also recorded daily. Pregnancy diagnosis by rectal palpation was carried out 3 months post-insemination. Pregnancy rates for all services were related to selected climatologicalmeasurementsand rectal temperatures. The results obtained indicate that elevated rectal, temperature,mean maximum and mean minimum temperaturesand relative humidity were detrimental to conception. The effect of the climatologicalfactor on conception is compounded by feed scarcity during the dry periods of the year.
The detrimental effects of high ambient temperatures,relative humidity and temperature-humidity index on pregnancy rates have been reported (1, 2, 3, 4, 5, 6, 7, 8, 9). Poor reproductiveperformanceassociatedwith thermal stress may be due to high temperatureacting on the developing embryo (10, 11) and or through maternal endocrine imbalance (12, 13).
Acknowledgement: The authors profoundly acknowledge the financial support of the National Animal Production Research Institute for this study. We are also indebted to Yusufu Hassan, Gabriel Opaluwa and Umaru Shehu for their technical assistance.
SEPTEMBER
1981 VOL. 16 NO. 3
331
THERIOGENOLOGY Because of lack of relevant informationfor Nigeria, the study reported here was undertaken to determine the effects of rectal and ambient temperatures and humidity on pregnancy rates following artificial insemination.
MATERIALS AND METHODS Fifty-eight sexually mature Bunaji and Bokoloji (Zebu) cows in the National Animal ProductionResearch Institute (NAPRI) farm at Shika ware used in this study. Five men were employed to detect estrus on a twentyfour-hour basis and a teaser bull was also used to aid effective estrus detection. Cows identified as being in estrus by allowing service were driven to a crush and were artificiallyinseminatedusing chilled semen from the same donor bulls for all services. Deep cervical inseminationwas employed. Approximately1 ml of chilled semen preserved in egg-yolk citrate and kept on ice blocks (S'C) in a flask was withdrawn in inseminatingpipette and deposited into the uterus at each insemination. A total of 113 inseminations for which rectal temperatureswere recorded at the time of insemination was carried out between 1978 and 1979. A centigrade clinical thermometer was used for recording rectal temperatures. Environmentaltemperatures and relative humidity were recorded daily using dry and wet bulbs thermometer. Pregnancy was determined by rectal palpation 3 months after artificial insemination.Correlation coefficientsanalysis, standard partial regression coefficientsanalysis and chi square were used to analyse the results. To determine the effect of weather condition surroundingthe breeding time, mean maximum and mean minimum ambient temperaturesand humidity recorded on the day of inseminationand one day after were correlated to pregnancy rates. The weather conditions for these two days were assumed to be representativeof the critical days in terms of heat sensivity surroundingthe breeding time because there were only relatively small changes in the mean daily weather conditions.
RESULTS Mean relative humidity in the morning and evening of the experimental period were 51.55% and 41.75% and mean maximum and mean minimum air temperatures were 31.15OC and 17.95OC respectively. Over all mean air temperature was 24.6oC. Mean daily duration of sunshine was 8 hours. Analysis of the data by the method of correlation coefficientsshowed that the variation in conceptionrates obtained was accounted for by collective effect of rectal temperature,ambient temperature and relative humidity. This was statistically significant (Pq.01). Standard partial regression coefficientswas used in ranking individual parameter'seffect on conceptionrates (CR). Comparison of the effect of climatologicaldata with that of rectal temperature revealed that closest associationwith pregnancy rates was shown by the mean rectal temperatureat the time of insemination (Pq.01) followed by the mean maximum and mean minimum ambient temperatures (Pc.05) one day post inseminationand finally by relative humidity one day post insemination (PX.05). Chisquare analysis (Table I) showed that as rectal temperatureincreased frQm 88*2'C to 4D.D°C, pregnancy rates decreased from 52% to 12% and this was
332
SEPTEMBER
1981 VOL. 16 NO. 3
THERIOGENOLOGY
TABLE RECTAL TEMPERATURE
Number Pregnant
Rectal Temperature'C
<
37.9
38.2 - 39.1
RELATED TO CONCEPTION
Expected Values
Number not Pregnant
RATES
Expected Values
Total Obser.,>+innE
15 (36%)
9
10
16
25
22 (52%)
18
27
31
49
15
34
24
39
42
71
71
113
5 (12x)**
39.2 - 40.0
42
Total
1
** PC.01
TABLE II EFFECT OF SEASON ON CONCEPTION
Mean Relative Humidity (X)
Season Jan. - March
(Dry)
Mean Air Temperature
24.7
April - May (Prerainy)
61.7
27.5
June - September (Rainy)
79.4
24.3
39.2
23.0
(Pre-dry)
SEPTEMBER
1981 VOL. 16 NO. 3
Daily Mean sunshine (Hours)
Conception Rate (%)
(OC)
20.2
Oct. - December
RATE
u (24)
21
( (17)
18
6.6
(27) (47)
57
8.6
( (25)
28
8.8
333
The level highly significant (PL. .Ol). by seasonal changes (Table II).
of
fertility
was also
affe’cte.d
OISCUSSION Rectal temperatures in cows above 39.7’C at the time of breeding Thisofinding agrees with the resulted in reduced fertility (4, 6). of above 39 C reduced conception from present study whgre temperature 52% at 38.2-39.1 C to 12% at 39.2-40°C, Average and maximum ambient temperatures the day after insemination were found to be related more closely to conception rate in heifers,, and.dairy cows than same measurement on the day of insemination (7). In another study it was found that there was a closer negative correlation between conception and average.temperatuce-humidity index i;HIh)of the second day before breeding thanoother days of the cycle No Hereford heifers exposed to 32.2 C for 72 hours after brLedi;g were pregnant as compared to 48% of those exposed to 21oC c.14). These authors concluded that in cattle the critical heat sensitivity Heat stress beginning 10 appears to last for 10 days post breeding. days after breeding during cool weather months did not decrease The percentage of hours during a LO-day fertility in cows (5, 12). period which were in excess of 26.6’C was importantin considering the effects of season on fertility (151. The stressful effects of diurnal temperature were found to-be.not only the result of the average maximum and minimum temperatures, but.also.the result of hours of exposure to heating. temperatures above..26.6’C and cooling temperatures below 21°C (16). Another study -revealed the need for a verification of the effect of humidity and maximum daily ambient temperature in fertility works f4). The results of our study regarding the adverse effects humidity on conception rate. factors are only secondary in temperature. The effects of co&eption.rate are likely to which influence the levels of nutrition for the animals is June to September, and worst January to March and April to
are in agreement with the above studies of ambient temperature and .relative However, our findings reveal that these importance to the effect of rectal these climatoloaical parameters on be complicated-by seasons of the year feed availability. The plane of at its best during the rainy season, during the dry and pre-rainy.seasons, May respectively (Table III.
The factors causing the decrease in fertility in the present study is complicated but it suggests that high rectal temperatures the experimental animals, elevated environmental temperatures and humidity are all contributing factors compounded with feed scarcity in the dry and pre-rainy seasons.
334
SEPTEMBER
1981 VOL. 16 NO. 3
of
THERIOGENOLOGY REFERENCES 1.
2.
Erb, R. E., Wilbur, J. W., and Hilton, J. H. (1940). Some factors affecting breeding efficiency in dairy cattle. J. Dairy Sci. -23: 549 Branton, C., Griffith, W. S., Hall, J. G., Johnston, J. E., and Patrick, T. E. (1954 - 55). Breeding difficulties of dairy cattle in Louisiana. Agr. Exp. Sta., Ann. Rept.
3.
Branton, C., Griffith, W. S., Norton, H. W., and Hall, J. G. (1956). Influence of heredity and environment on fertility of dairy cattle. J. Dairy Sci. -39: 933.
4.
Long, C. R., Nipper, W. A., and Vincent, C. R. (1969). Body temperature and estrous control of beef cattle. J. Ani. Sci. -28: 146.
5.
Wiersma, F., and Stott, G. H. (1969). New concepts in the physiology of heat stress in dairy cattle of interest to engineers. Trans. of ASAE. -12(l), 130
6.
Gwazdauskas, F. C., Thatcher, W. W., and Wilcox, C. J. (1972). Physiological, Environmental, and Hormonal Factors at Insemination which may affect conception. Ann. Meet. of the Am. Dairy Sci. Ass.
7.
Gwazdanskas, F. C., Wilcox, C. J. and Thatcher, W. W. (1975). Environmental and management factors affecting conception rate in subtropical climate. J. Dairy Sci. -58: 88.
8.
Ingraham, R. H., Gillette, D. D., and Wagner, W. C. (1974). Relationship of temperature and humidity to conception rate of Holstein cows in subtropical climate. J. Dairy Sci. -57: 476
9.
Ingrahm, R. H., Stanley, R. W., and Wagner, W. C. (1976). Relationship of temperature and humidity to conception rate of Holstein cows in Hawaii. J. Dairy Sci. 2, (12), 2086.
0.
Alliston, C. W., Howarth, B., and Ulberg, L. C. (1965). Embryonic mortality following culture in vitro of one and two-cell rabbit eggs at elevated temperatures. J. Reprod. Fert. 9: 337.
SEPTEMBER
1981 VOL. 16 NO. 3
335
THERIOGENOLOCY
11.
Burfening, P. J., Alliston, C. W., and Ulberg, L. C. (1969). Gross morphology and predictability for survival of 4-day
rabbit embryos following stress during the first cleavage division. J. Exp. Zool. 1'70:55. 12.
Wiersma, F., and Stott, G. H., 1966. Microclimate.modificatior ,forhot-weather stress relief of dairy cattle. Transactions of ASAE. 2, (31, 309.
13.
Stott, G. H., and Williams, R. J. (1962). Causes of low breeding efficiency in dairy cattle-associated with seasonal. high temperatures. J. Dairy Sci. 45: 1369-1375.
14.
Dunlap, S. E., and Vincent, C. K. (19711. Influence of postbreeding thermal stress on conception rate in beef cattle. J. Ani. Sci: '32:1216.
15.
Kelly, M. S., and Hurst, V. (19631. The effect of season on fertility of the dairy bull and dairy cow. J. Amer. Vet. Med. Awn. 243: 40.
16,
Brody, S., Bagsdlale, A. C., Yeck,.R. G., and Dorothy, W. (1955). Environmental physiology and shelter engineering with-special reference to domestic animals. XXXIII. Milk production, feed and water consumption, and body weight of Jersey and Holstein cows in relation to several diurnal temperature rhythms. MO. Agr. Expt. Res, Bull. 791.
336
SEPTEMBER
1981 VOL. 16 NO. 3
AND ~IDITY
ON CONCEPTION RATES
A. Y. Zakari,a E.C.I. Molokwu
b
and D. I. K. OsoriC
Ahmadu Be110 University, Zaria, Nigeria, "National Animal Production Research Institute. b Department of Veterinary Physiology & Pharmacology. % epartment of Veterinary.Surgery& Medicine. Received for publication: March 26, 1981 accepted: July 2, 1981 ABSTRACT One hundred and thirteen inseminationswere performed for which rectal temperatureswere taken at the time of inseminations. Climatological factors were also recorded daily. Pregnancy diagnosis by rectal palpation was carried out 3 months post-insemination. Pregnancy rates for all services were related to selected climatologicalmeasurementsand rectal temperatures. The results obtained indicate that elevated rectal, temperature,mean maximum and mean minimum temperaturesand relative humidity were detrimental to conception. The effect of the climatologicalfactor on conception is compounded by feed scarcity during the dry periods of the year.
The detrimental effects of high ambient temperatures,relative humidity and temperature-humidity index on pregnancy rates have been reported (1, 2, 3, 4, 5, 6, 7, 8, 9). Poor reproductiveperformanceassociatedwith thermal stress may be due to high temperatureacting on the developing embryo (10, 11) and or through maternal endocrine imbalance (12, 13).
Acknowledgement: The authors profoundly acknowledge the financial support of the National Animal Production Research Institute for this study. We are also indebted to Yusufu Hassan, Gabriel Opaluwa and Umaru Shehu for their technical assistance.
SEPTEMBER
1981 VOL. 16 NO. 3
331
THERIOGENOLOGY Because of lack of relevant informationfor Nigeria, the study reported here was undertaken to determine the effects of rectal and ambient temperatures and humidity on pregnancy rates following artificial insemination.
MATERIALS AND METHODS Fifty-eight sexually mature Bunaji and Bokoloji (Zebu) cows in the National Animal ProductionResearch Institute (NAPRI) farm at Shika ware used in this study. Five men were employed to detect estrus on a twentyfour-hour basis and a teaser bull was also used to aid effective estrus detection. Cows identified as being in estrus by allowing service were driven to a crush and were artificiallyinseminatedusing chilled semen from the same donor bulls for all services. Deep cervical inseminationwas employed. Approximately1 ml of chilled semen preserved in egg-yolk citrate and kept on ice blocks (S'C) in a flask was withdrawn in inseminatingpipette and deposited into the uterus at each insemination. A total of 113 inseminations for which rectal temperatureswere recorded at the time of insemination was carried out between 1978 and 1979. A centigrade clinical thermometer was used for recording rectal temperatures. Environmentaltemperatures and relative humidity were recorded daily using dry and wet bulbs thermometer. Pregnancy was determined by rectal palpation 3 months after artificial insemination.Correlation coefficientsanalysis, standard partial regression coefficientsanalysis and chi square were used to analyse the results. To determine the effect of weather condition surroundingthe breeding time, mean maximum and mean minimum ambient temperaturesand humidity recorded on the day of inseminationand one day after were correlated to pregnancy rates. The weather conditions for these two days were assumed to be representativeof the critical days in terms of heat sensivity surroundingthe breeding time because there were only relatively small changes in the mean daily weather conditions.
RESULTS Mean relative humidity in the morning and evening of the experimental period were 51.55% and 41.75% and mean maximum and mean minimum air temperatures were 31.15OC and 17.95OC respectively. Over all mean air temperature was 24.6oC. Mean daily duration of sunshine was 8 hours. Analysis of the data by the method of correlation coefficientsshowed that the variation in conceptionrates obtained was accounted for by collective effect of rectal temperature,ambient temperature and relative humidity. This was statistically significant (Pq.01). Standard partial regression coefficientswas used in ranking individual parameter'seffect on conceptionrates (CR). Comparison of the effect of climatologicaldata with that of rectal temperature revealed that closest associationwith pregnancy rates was shown by the mean rectal temperatureat the time of insemination (Pq.01) followed by the mean maximum and mean minimum ambient temperatures (Pc.05) one day post inseminationand finally by relative humidity one day post insemination (PX.05). Chisquare analysis (Table I) showed that as rectal temperatureincreased frQm 88*2'C to 4D.D°C, pregnancy rates decreased from 52% to 12% and this was
332
SEPTEMBER
1981 VOL. 16 NO. 3
THERIOGENOLOGY
TABLE RECTAL TEMPERATURE
Number Pregnant
Rectal Temperature'C
<
37.9
38.2 - 39.1
RELATED TO CONCEPTION
Expected Values
Number not Pregnant
RATES
Expected Values
Total Obser.,>+innE
15 (36%)
9
10
16
25
22 (52%)
18
27
31
49
15
34
24
39
42
71
71
113
5 (12x)**
39.2 - 40.0
42
Total
1
** PC.01
TABLE II EFFECT OF SEASON ON CONCEPTION
Mean Relative Humidity (X)
Season Jan. - March
(Dry)
Mean Air Temperature
24.7
April - May (Prerainy)
61.7
27.5
June - September (Rainy)
79.4
24.3
39.2
23.0
(Pre-dry)
SEPTEMBER
1981 VOL. 16 NO. 3
Daily Mean sunshine (Hours)
Conception Rate (%)
(OC)
20.2
Oct. - December
RATE
u (24)
21
( (17)
18
6.6
(27) (47)
57
8.6
( (25)
28
8.8
333
The level highly significant (PL. .Ol). by seasonal changes (Table II).
of
fertility
was also
affe’cte.d
OISCUSSION Rectal temperatures in cows above 39.7’C at the time of breeding Thisofinding agrees with the resulted in reduced fertility (4, 6). of above 39 C reduced conception from present study whgre temperature 52% at 38.2-39.1 C to 12% at 39.2-40°C, Average and maximum ambient temperatures the day after insemination were found to be related more closely to conception rate in heifers,, and.dairy cows than same measurement on the day of insemination (7). In another study it was found that there was a closer negative correlation between conception and average.temperatuce-humidity index i;HIh)of the second day before breeding thanoother days of the cycle No Hereford heifers exposed to 32.2 C for 72 hours after brLedi;g were pregnant as compared to 48% of those exposed to 21oC c.14). These authors concluded that in cattle the critical heat sensitivity Heat stress beginning 10 appears to last for 10 days post breeding. days after breeding during cool weather months did not decrease The percentage of hours during a LO-day fertility in cows (5, 12). period which were in excess of 26.6’C was importantin considering the effects of season on fertility (151. The stressful effects of diurnal temperature were found to-be.not only the result of the average maximum and minimum temperatures, but.also.the result of hours of exposure to heating. temperatures above..26.6’C and cooling temperatures below 21°C (16). Another study -revealed the need for a verification of the effect of humidity and maximum daily ambient temperature in fertility works f4). The results of our study regarding the adverse effects humidity on conception rate. factors are only secondary in temperature. The effects of co&eption.rate are likely to which influence the levels of nutrition for the animals is June to September, and worst January to March and April to
are in agreement with the above studies of ambient temperature and .relative However, our findings reveal that these importance to the effect of rectal these climatoloaical parameters on be complicated-by seasons of the year feed availability. The plane of at its best during the rainy season, during the dry and pre-rainy.seasons, May respectively (Table III.
The factors causing the decrease in fertility in the present study is complicated but it suggests that high rectal temperatures the experimental animals, elevated environmental temperatures and humidity are all contributing factors compounded with feed scarcity in the dry and pre-rainy seasons.
334
SEPTEMBER
1981 VOL. 16 NO. 3
of
THERIOGENOLOGY REFERENCES 1.
2.
Erb, R. E., Wilbur, J. W., and Hilton, J. H. (1940). Some factors affecting breeding efficiency in dairy cattle. J. Dairy Sci. -23: 549 Branton, C., Griffith, W. S., Hall, J. G., Johnston, J. E., and Patrick, T. E. (1954 - 55). Breeding difficulties of dairy cattle in Louisiana. Agr. Exp. Sta., Ann. Rept.
3.
Branton, C., Griffith, W. S., Norton, H. W., and Hall, J. G. (1956). Influence of heredity and environment on fertility of dairy cattle. J. Dairy Sci. -39: 933.
4.
Long, C. R., Nipper, W. A., and Vincent, C. R. (1969). Body temperature and estrous control of beef cattle. J. Ani. Sci. -28: 146.
5.
Wiersma, F., and Stott, G. H. (1969). New concepts in the physiology of heat stress in dairy cattle of interest to engineers. Trans. of ASAE. -12(l), 130
6.
Gwazdauskas, F. C., Thatcher, W. W., and Wilcox, C. J. (1972). Physiological, Environmental, and Hormonal Factors at Insemination which may affect conception. Ann. Meet. of the Am. Dairy Sci. Ass.
7.
Gwazdanskas, F. C., Wilcox, C. J. and Thatcher, W. W. (1975). Environmental and management factors affecting conception rate in subtropical climate. J. Dairy Sci. -58: 88.
8.
Ingraham, R. H., Gillette, D. D., and Wagner, W. C. (1974). Relationship of temperature and humidity to conception rate of Holstein cows in subtropical climate. J. Dairy Sci. -57: 476
9.
Ingrahm, R. H., Stanley, R. W., and Wagner, W. C. (1976). Relationship of temperature and humidity to conception rate of Holstein cows in Hawaii. J. Dairy Sci. 2, (12), 2086.
0.
Alliston, C. W., Howarth, B., and Ulberg, L. C. (1965). Embryonic mortality following culture in vitro of one and two-cell rabbit eggs at elevated temperatures. J. Reprod. Fert. 9: 337.
SEPTEMBER
1981 VOL. 16 NO. 3
335
THERIOGENOLOCY
11.
Burfening, P. J., Alliston, C. W., and Ulberg, L. C. (1969). Gross morphology and predictability for survival of 4-day
rabbit embryos following stress during the first cleavage division. J. Exp. Zool. 1'70:55. 12.
Wiersma, F., and Stott, G. H., 1966. Microclimate.modificatior ,forhot-weather stress relief of dairy cattle. Transactions of ASAE. 2, (31, 309.
13.
Stott, G. H., and Williams, R. J. (1962). Causes of low breeding efficiency in dairy cattle-associated with seasonal. high temperatures. J. Dairy Sci. 45: 1369-1375.
14.
Dunlap, S. E., and Vincent, C. K. (19711. Influence of postbreeding thermal stress on conception rate in beef cattle. J. Ani. Sci: '32:1216.
15.
Kelly, M. S., and Hurst, V. (19631. The effect of season on fertility of the dairy bull and dairy cow. J. Amer. Vet. Med. Awn. 243: 40.
16,
Brody, S., Bagsdlale, A. C., Yeck,.R. G., and Dorothy, W. (1955). Environmental physiology and shelter engineering with-special reference to domestic animals. XXXIII. Milk production, feed and water consumption, and body weight of Jersey and Holstein cows in relation to several diurnal temperature rhythms. MO. Agr. Expt. Res, Bull. 791.
336
SEPTEMBER
1981 VOL. 16 NO. 3