D. Ogwu

Effects of experimental Trypanosoma vivax infection on first-, second-, and third-trimester pregnancy in heifers.

The effects of Trypanosoma vivax on pregnancy were studied in 18 heifers. The heifers were bred by a proven bull and divided into three groups of six heifers each. In the first group, four heifers were infected with T . vivax on Day 60 (first trimester) of pregnancy; two other pregnant heifers were uninfected controls. The second and third groups were similarly infected in the fourth (second trimester) and seventh (third trimester) month of pregnancy. One infected heifer in the first-trimester group aborted 39 days postinfection (p.i.); the remaining three had relatively normal gestation and parturition. In the second-trimester group, the pregnancies were carried to term with normal deliveries. In the third-trimester group, three infected heifers (75%) had premature deliveries while the fourth died about three hours after the full-term calf was pulled out. All of the control heifers had normal gestation and parturition. No gross abnormalities were seen in the placentae of the infected heifers, but histological sections of the heifers infected in the third trimester of pregnancy revealed more mononuclear cells than in those of the uninfected controls. Postmortem examination of the dead premature calves showed lymphadenopathy, splenomegaly, serous atrophy of perirenal and pelvic fat, epicardial petechiae, and blood-tinged peritoneal and pericardial fluids. Histologically, there were slight myocardial haemorrhages and edema. T. vivax was recovered from the blood of one of the premature calves. Both birth weights and PCV were affected by the experimental maternal infection in the first- and third-trimester calves. The birth weights and PCV of calves of infected dams were lower than those for the calves of the control heifers. This work therefore demonstrates transplacental transmission of T. vivax in heifers.

Effects of experimental Trypanosoma vivax on fertility of heifers

Abstract Six heifers were used in a series of experiments to study the effects of experimental Trypanosoma vivax infection on bovine reproduction. Four three-year-old Zebu heifers were intravenously inoculated with T. vivax-strain Y58 — on days 14 and 16 of their estrous cycle and two control heifers in the same phase of estrus were not infected. All the heifers were bred in the research pens with a proven bull. The four infected heifers were bred at the first wave of parasitemia and the onset of pyrexia which characterised the infection. All the heifers were examined rectally 40 days after breeding. The four infected heifers were not pregnant but the two controls were. The infected heifers later became anestrous during the experimental period of more than five months. It is concluded that trypanosomiasis may contribute to high infertility rates in cattle kept in endemic areas.

Effects of Trypanosoma vivax on pregnancy of Yankasa sheep and the results of homidium 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.

Genital lesions in experimental Trypanosoma congolense infection in heifers

A group of normocyclic heifers experimentally infected with Trypanosoma congolense (strain 2295) became anoestrous within 50 days of infection. This followed a dramatic loss of body condition which characterised the onset of parasitaemia, pyrexia and anaemia. Grossly, the ovaries of the infected heifers were atrophic and weighed significantly less than those of the controls (P < 0.05). Histopathological sections revealed multiple follicular cystic degeneration and a complete absence of corpora lutea. In the uterus, there was massive endometrial mononuclear cell infiltration, glandular atrophy, periglandular cell infiltration, myometrial atrophy and fibroplasia. There was cellular infiltration into the cervix which had non-secretory desquamated mucosa. The vaginal lesions were characterised by mononuclear cell infiltration and necrosis. The severity of the lesions was directly related to the duration of infection.

Effects of the reproductive status in Zebu heifers on the immunoglobulin M and G levels in bovine Trypanosoma vivax infection

Immunoglobulin M and G levels in bovine Trypanosoma vivax infection were compared in non-pregnant, first, second and third trimester pregnant heifers. All the infected heifers showed a significant rise in IgM levels when compared to the non-infected controls. 7–8 fold increases were recorded. There were however differences in the rate of increases and ability to maintain peak level response (P <0.01) between the groups. Infected pregnant heifers in the first and second trimester responded better than infected non-pregnant and infected heifers in the third trimester pregnancy. In all the groups, the differences between the infected and control heifers were highly significant (P <0.001). The IgG levels showed a similar pattern of increases in infected heifers though response was gradual. In the different groups 1.4–2.5-fold increases were recorded. These were significantly different from levels in the control (P <0.01). Again, pregnant heifers responded better than non-pregnant heifers except those in the third trimester pregnancy. The results correlated with the observation that given the same conditions, clinical manifestation of T. vivax infection is more severe in non-pregnant than in pregnant heifers except those in advanced pregnancy.

Bovine streptothricosis and reproduction in Northern Nigeria: a case study.

A group of cows, which were naturally infected with streptothricosis, was observed for 17 months. The genitalia were examined per rectum, at least twice monthly to determine the ovarian activity. During the period of observation, 83.3% of the lightly affected cows were pregnant or had calves, while only 33.3% of the moderately/severely affected cows had calves. It is suggested that streptothricosis, like any other debilitating disease, affects reproductive performance, and in the case of severe, localized, perineal infection, the disease results in mechanical interference with mating.

Effect of different husbandry systems on the reproductive development of post-weaning ram lambs under tropical conditions

Two groups of three-to four-month-old weaning ram lambs were studied for 20 months, beginning with weaning at between three and four months. Group 1 was comprised of nine ram lambs which were reared under an intensive husbandry system, and given standard nutrition and mineral supplements throughout the study. Group 2 was comprised of nine rams which were reared under the traditional nomadic/extensive management system, in which the only source of feed was the available pasture. The reproductive traits studied include: age, weight and scrotal circumference at puberty and at all corresponding ages up to 23 months, libido and sexual dexterity and semen characteristics at puberty and all corresponding ages. In the intensively managed rams, the average age at puberty was 6.4+/-0.5 mos. The averages of the other parameters at puberty were: body weight (BW), 21.7+/-2.5kg; scrotal circumference (SC), 18.5+/-1.3cm; libido score, 1.7+/-0.7 and sexual dexterity, 1.7:0.8. In the extensively managed rams, the average age at puberty was 7.8+/-0.3 mos. The average values of the various parameters at puberty were: BW, 17.3+/-1.2kg; SC, 15.2+/-1.4cm; libido score, 3.2+/-0.6 and sexual dexterity, 3.2:1.8. The inter- and intra-group variations in all the parameters at puberty and at all corresponding ages were significant. The average morphological sperm cell abnormalities at puberty were: 25.2+/-3.4% and 31.6+/-8.3% for rams reached puberty and at all corresponding ages than the extensively reared flock. Certain factors that influence post-weaning reproductive development and performance are discussed.

Cryptorchidism and malformations of the scrotum and testes of donkeys.

Scrotal palpations of 274 donkeys revealed 74 cases of cryptorchidism, which is an incidence of approximately 30%. Three donkeys were found without scrotum evident and with ectopic testes. The histological changes in the ectopic testes were noted.

Effect of Brucellaabortus infection on spermatogenesis in three Zebu bulls (Bosindicus). A case report

Abstract This case report addresses the occurrence of Brucellosis and its effect on the cattle in developing countries. Three Zebu bulls ( Bos indicus ) are presented and the clinical and pathologic signs are described. Conception rates declined following an abortion storm in one herd and without prior abortions in another herd. Semen collected by electro-ejaculation was found to be azoospermic or with very few spermatozoa. B. abortus was isolated from seminal vesicles, testes and epididymides. Organs affected and showing microscopic lesions were testes, epididymides and seminal vesicles. The latter were not consistently affected. None of the bulls showed impairment of libido or breeding capacity.

Effect of chemotherapy on semen characteristics of Balami rams infected with Anaplasma ovis

Six intact Balami rams were experimentally infected with Anaplasma ovis. Another six were infected one month after splenectomy and six others served as controls. Clinical manifestations of the disease, first observed between 5 to 7 days post-infection, were more severe and prolonged in the splenectomised-infected than in the intact-infected group. There was progressive deterioration in semen quality, which was also significantly more severe and prolonged in the splenectomised than in the intact-infected rams. Following treatment with long-acting terramycine, clinical recovery occurred earlier in the intact-infected (1–4 weeks) than in the splenectomised-infected group (5–7 weeks). A similar pattern was observed in post-treatment improvement in the spermiogram. However, although the infected animals recovered clinically by 1–7 weeks post-treatment, restoration of the reproductive potential did not occur for 20 to 25 weeks. It appears that stress factors may aggravate the deliterious effects of anaplasmosis.