The effects of trypanosomosis on sperm morphology in Zebu x Friesian crossbred bulls.

Detailed studies of sperm morphological abnormalities were carried out on 12 Zebu x Friesian crossbred bulls used in a study of the effects of trypanosomosis. Four bulls were infected with T. vivax, another four with T. congolense, while four served as controls. The infected bulls developed chronic trypanosomosis. All the bulls initially had very low sperm morphological abnormalities that were within acceptable limits for fertile animals. After infection there was a rapid and progressive increase in all sperm abnormalities. Spermatozoa of infected bulls were highly deformed with multiple morphological defects. Mean percentage pre-infection baseline values prior to infection for acrosomal, sperm-head, detached heads, proximal cytoplasmic droplets, distal cytoplasmic droplets, sperm-tail, midpiece and total sperm morphological defects ranged between 0.1 +/- 0.1 for acrosomal and 8.3 +/- 3.2 for total morphological abnormalities in the semen of the bulls. All the infected bulls developed sperm morphological abnormalities of more than a mean of 40.0% from the 4th week after infection until the end of the investigation and were considered unfit for breeding. At 7 weeks post-infection (PI) until the end of the study (12 weeks PI), the controls had a mean of less than 5% sperm morphological defects, while the infected bulls had 100%. Mean percentage values of sperm morphological defects throughout the duration of the investigation for control bulls were low and within the normal range for fertile bulls. These values differed significantly (p<0.001) from the elevated values of the infected bulls. The results show that trypanosomosis due to T. vivax or T. congolense infection can render Zebu x Friesian crossbred bulls unfit for breeding within a very short time. The resultant infertility could be of economic importance in trypanosomosis-endemic sub-Saharan Africa where Zebu x Friesian crossbred bulls are kept.

Effects of Trypanosoma vivax and Trypanosoma congolense infections on the reaction time and semen characteristics of Zebu (Bunaji) x Friesian crossbred bulls.

The effect of trypanosomosis on reaction time and semen characteristics of 12 Zebu (Bunaji) x Friesian crossbred bulls aged between 3 and 5 years was studied for a duration of 12 weeks. Four of the bulls were infected with Trypanosoma vivax, another four with Trypanosoma congolense and the remaining four bulls served as controls. Rectal temperatures and haematological parameters were monitored twice weekly. The pre-infection mean value of the rectal temperature was 38.3 degrees C, and this rose to a mean of between 40.5 and 41.1 degrees C in the infected animals. Concurrently, the infected animals exhibited signs of anaemia shown by pale mucous membranes and decreased packed cell volume (PCV), weight loss, lethargy, weakness and dullness. The reaction time (ejaculation time) of semen collection significantly increased from a pre-infection mean value of 20.46-25.14 s to a mean of 290.33-301.15 s within 12 weeks post-infection. Semen characteristics deteriorated progressively within the same period in the infected bulls. There were highly significant and drastic decreases in sperm concentration and volume of semen and increases in sperm morphological defects. By the third week, all the infected bulls were unfit for breeding because of very poor semen characteristics. Deterioration, also characterized by oligospermia at 6 weeks post-infection in all bulls which later culminated in azoospermia in two bulls infected with T. vivax and two bulls infected with T. congolense continued to the end of the investigation. The present results indicate that trypanosomosis due to T. vivax and T. congolense infections is very pathogenic and devastating in its effect on the reaction time (ejaculation time) and semen characteristics which resulted in very poor semen quality. The practical implication is infertility and sterility in Zebu x Friesian crossbred bulls in trypanosome endemic areas.

Effects of Trypanosoma vivax on pregnancy of Yankasa sheep and the results of homidum chloride chemotherapy.

Three groups of pregnant Yankasa ewes, made up of six ewes in each group were assigned at random to first, second and third trimester of pregnancy studies. The ewes were experimentally infected with T. vivax to study the effects of the infection on pregnancy and the results of Novidium Chemotherapy. Three pregnant uninfected ewes served as controls. Fourteen days post infection, the ewes in each trimester study, were paired by weight and assigned to two groups of three ewes each. One group was treated with Novidium while the other group remained untreated. Of the three ewes in each group, one ewe was killed humanely at 21 days post infection and another at the end of the trimester period. In the first trimester, a ewe with partial fetal resorption was observed among the untreated ewes. Fetal death in-utero and expulsion of an autolyzed fetus was observed among the treated ewes. In the second trimester, abortion and almost complete fetal resorption were observed among the untreated ewes. Fetal death in-utero and expulsion of an autolyzed fetus was observed among the treated ewes. In the third trimester, abortions were observed among the untreated ewes. Abortion of a live fetus and a case of dystocia were observed among the treated ewes. Ewes in the second and third trimesters of pregnancy were more susceptible to the infection, with ewes in the third trimester being most susceptible, as measured by the number of abortions and death of ewes. Fetuses from the untreated ewes in the three trimesters of pregnancy were lower in body weights, than the fetuses from the treated ewes. The uninfected control ewes carried the pregnancies to term. Novidium chemotherapy at 14 days post infection was not beneficial in ameliorating the pathogenicity of T. vivax infection on pregnancy in Yankasa ewes. T. vivax infection of only 14 days was enough to cause irreversible pathology in Yankasa fetuses evidenced by death of fetuses in-utero, dystocia and abortions irrespective of Novidium chemotherapy.

Prevalence of bovine campylobacteriosis in indigenous cattle of three states in Nigeria.

A survey of bovine campylobacteriosis in breeding bulls and cows was carried out in the states of Kaduna, Kano and Borno. Six hundred and eighty nine cattle composed of 585 and 104 breeding bulls and cows respectively were sampled. Campylobacter fetus subsp. venerealis was isolated from 12 bulls while Campylobacter fetus subsp. fetus was isolated from three of them. Campylobacter fetus subsp. fetus was isolated from four cows while Campylobacter fetus subsp. veneralis was isolated from one cow. The overall prevalence of campylobacteriosis in the three states was 2.9% (20/689). The result of the study identifies Campylobacter fetus subsp. venerealis as the agent of enzootic infertility in Nigeria and suggests that it may be a significant problem.

Campylobacter fetus subsp. jejuni in poultry reared under different management systems in Nigeria.

Cloacal swabs from 487 live birds in 36 flocks and 70 poultry carcasses were cultured for Campylobacter fetus subsp. jejuni. It was isolated from 12.3% of the birds in 19 flocks. Chickens, turkeys, and guinea fowl differed from one another in isolation rates of the organism. Management system affected its occurrence, and only 7.1% of eviscerated carcasses yielded it. It was concluded that bird species, management system, and immersing slaughtered poultry in boiling water before dressing affect recovery of C. fetus subsp. jejuni from live birds and carcasses.