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Effect of novidium chemotherapy on elevated values of spermatozoa morphological abnormalities consequent to Trypanosoma vivax or Trypanosoma congolense infection was investigated in Zebu bulls. Six of the 12 infected animals were treated with novidium at the end of the twelfth week post-infection and studied for a period of 12 weeks post-chemotherapy. Parasites disappeared from the bloodstream within 3 days post-chemotherapy, but elevated values of spermatozoa morphological abnormalities which also decreased gradually within a period of 12 weeks post-chemotherapy were still significantly (P < 0.001) higher than the pre-infection values, values for control bulls and also considerably higher than the optimum value of 20% for most fertile bulls. Therefore, novidium chemotherapy was not effective at 12 weeks post-treatment in reducing the elevated values of spermatozoa morphological abnormalities to values found in fertile bulls and to the pre-infection levels for the bulls. The results showed that the infected bulls might still be sub-fertile 12 weeks after novidium chemotherapy owing to elevated spermatozoa morphological abnormalities.

Summary The effect of the trypanocidal drug Novidium R on elevated ejaculation time and deteriorated semen characteristics was studied in Zebu cattle infected with T. vivax and T. congolense . Two groups, comprising six bulls per group, were infected with Trypanosoma vivax or Trypanosoma congolense while three bulls served as controls. Chemotherapy was carried out 12 weeks post-infection on three bulls from each group, leaving three bulls untreated while three bulls served as uninfected controls. Blood samples from treated bulls were all negative for trypanosomes 3 days post-chemotherapy. The animals also had normal body temperature. As the study progressed, clinical signs associated with trypano-somiasis, such as anaemia and cachexia, disappeared gradually in treated bulls. There was some improvement in semen characteristics of some of the bulls at 10 weeks post-chemotherapy with Novidium R . However, all bulls infected with T. vivax or T. congolense irrespective of Novidium chemotherapy still had poor semen characteristics manifested by all or some of the following: decreased volume of semen, oligospermia, azoospermia and elevated incidence of spermatozoa morphological abnormalities. They were thus unsuitable for breeding.

Mild acid-hydrolysis of erythrocyte surface sialic acids of the trypanotolerant Ndama and the trypanosusceptible White/Fulani Zebu breeds of cattle was performed. The cleaved sialic acids from the two breeds of cattle were simultaneously subjected to polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate (SDS-PAGE), along with commercial standard N-acetylneuraminic acid (MW 309.28), blank gel and plasma proteins. The cleaved sialic acids migrated in the globulin fractions, as shown by the plasma protein electrophoresis. While the Ndama and the Zebu erythrocytes had one migrating band each of which coincided with the standard N-acetylneuraminic acid, the Ndama had another trailing band of sialic acid, of an estimated molecular weight of 30 kDa, which may account for the higher erythrocyte sialic acid concentrations of the Ndama. This additional band was absent in the Zebu. All these bands were readily reproducible.

Twenty-four Zebu bulls were used in a 12-wk long study. Eight bulls were infected with T. vivax , eight others with T. congolense and eight bulls served as controls. All the infected bulls developed chronic trypanosomiasis. Mean percentage base-line values prior to infection for acrosomal, sperm-head, detached heads, proximal cytoplasmic droplets, distal cytoplasmic droplets, sperm-tail, midpiece and total sperm morphological abnormalities ranged between 0.1±0.1 for acrosomal and 8.7±3.4 for total morphological abnormalities in the semen of the bulls. These values were very low and within the range of those for fertile bulls. Following infection, there was a progressive increase in the mean values of all the abnormalities. Peak percentage mean values recorded for total sperm morphological abnormalities in the course of the investigation in the bulls infected with T. vivax and T. congolense and in the controls were 95±7.2, 100±0 and 7.9±5.0, respectively. Mean percentage values throughout the duration of the investigation for control bulls were low and within the normal range for fertile bulls. These values differed (P The results indicate that trypanosomiasis due to either T. vivax or T. congolense infections can cause a marked increase in morphological abnormalities of spermatozoa which can, in turn reduce the fertility of breeding bulls.

A comparative study of haematological changes subsequent to Trypanosoma vivax and Trypanosoma congolense infections was carried out using 24 Zebu bulls during a period of 12 weeks. Eight bulls were infected with T. vivax, another eight with T. congolense and eight served as controls. Infected bulls developed chronic trypanosomiasis which was characterized by many clinical manifestations including intermittent pyrexia. Elevated rectal temperatures of up to 105 and 106°F were recorded, respectively, in all bulls infected with T. vivax or T. congolense. Mean parasitaemia was higher and more chronic in T. congolense-infected bulls and ranged between means of 0 and 3.06 in all infected bulls. There was a slight and transient drop in packed cell volume (PCV) of T. vivax-infected bulls as against a marked and more chronic drop in T. congolense-infected bulls. mean PCV of T. vivax- and T. congolense-infected bulls and controls ranged between 28 and 38, 17 and 38, and 31 and 38%, respectively. Haemoglobin (Hb) concentrations also decreased in infected bulls. The decrease was greater and more chronic in the T. congolense-infected bulls. Values ranged between means of 10.47 and 13.84, 5.44 and 14.16, and 10.24 and 14.12 g dl−1 in T. vivax- and T. congolense-infected and control bulls, respectively. Total plasma proteins also decreased in infected bulls; this was more marked in the T. congolense-infected group. Values for T. vivax-infected, T. congolense-infected and control bulls ranged between means of 7.66 and 8.99, 6.26 and 8.81, and 7.94 and 8.78 g dl−1, respectively. The results indicate that T. congolense was more pathogenic than T. vivax and caused more severe and chronic pyrexia, parasitaemia, and anaemia (as indicated by a greater decline of PCV and Hb concentrations and total plasma proteins). For all parameters studied, the T. vivax-infected bulls differed significantly from the control group (P

Differences in the distribution and concentration of O-acetyl and glycolyl groups in erythrocyte sialic acids of trypanotolerant N'dama and trypanosusceptible Zebu cattle were investigated. Erythrocyte surface sialic acid concentrations were 25.4 +/- 5.5 mg per dl and 5.9 +/- 0.97 mg per dl in N'dama and Zebu animals, respectively. In N'damas, O-acetyl and glycolyl groups were present in concentrations of 16.4 +/- 4.3 mg per dl and 12.8 +/- 2.9 mg per dl, respectively, whereas the corresponding values in Zebus were 2.8 +/- 5.0 mg per dl and 7.6 +/- 1.7 mg per dl, respectively. The differences between N'dama and Zebu cattle in surface sialic acids and in O-acetyl and glycolyl groups were significant (P0.01 to0.001). N'dama erythrocyte sialic acids had more O-acetyl than glycolyl groups while those of Zebus had less O-acetyl than glycolyl groups. These findings may be relevant to the trypanotolerance of N'dama cattle.

Erythrocyte surface sialic acid concentrations were measured in the trypano-tolerant Ndama and trypano-susceptible Zebu breeds of cattle. All animals were uninfected and had no records of previous exposure to infection by African pathogenic trypanosomes. Ndama adults had significantly (P less than 0.001) higher erythrocyte surface sialic acid concentrations than Ndama calves. Ndama adults and calves had significantly (P less than 0.001) higher erythrocyte surface sialic acid concentrations than Zebu adults. There were no significant differences between the packed cell volume (PCV), haemoglobin (Hb) concentrations and total leukocyte counts (WBC) of these breeds. The finding of much higher erythrocyte surface sialic acid concentrations (about 7-fold) in the Ndama than in the Zebu is discussed in relation to the induction of anaemia by trypanosome sialidase in both breeds and to how a relative trypano-tolerance may occur in the Ndama.

Sixty zebu heifers were divided into three equal groups and reared on isocaloric diets but on different levels of protein. The protein levels were 19.17% (high), 13.37% (medium; NRC recommendations) and 8.3% (low). All animals were examined weekly per rectum for the presence of follicles and corpora lutea and also checked daily for standing heat. The presence of a mature corpus luteum was considered to indicate the attainment of puberty. Body weight and pelvic dimensions were taken at biweekly intervals. Intact bulls were introduced to heifers after they reached puberty and once they reached 200 kg live weight. Pregnancy diagnosis was carried out at 60, 90 and 120 days following introduction of bulls. Mean age at puberty for heifers in the high protein group (570.4 days), medium protein group (640.8 days) and low protein group (704.2 days) differed significantly (P

Eight Zebu cattle were infected with Trypanosoma vivax stock Y58, while 8 served as uninfected controls. The infected animals developed early leukopenia due to concomitant lymphopenia and neutropenia. It is suggested that an increase in trypanosomal antigens and neuraminidase in the infected cattle at this time may have an effect on peripheral leukocytes.

Haemoglobin-binding protein (Haptoglobin, Hp) was assayed in the sera of control and zebu calves with acute T. vivax infection. Hp in control Zebu calves ranged between 123.5 and 236.5 mg dl −1 while Hp in the infected calves was too low to measure or absent. It was suggested that absence of Hp in the infected calves may be as a result of gradual intravascular haemolysis and removal of the Hp-Hb complex by the reticulo-endothelial system.

The effect of trypanosomiasis on reaction time and semen characteristics of 24 Zebu bulls was studied. Eight of the bulls were infected with T. vivax , another eight with T. congolense and the remaining eight bulls served as controls. The preinfection mean value of the rectal temperature was 101.0 °F, and this rose to a mean of between 104·5 and 105·5 °F in the infected animals. Concurrently the latter animals exhibited signs of anaemia shown by pale mucous membranes and decreased PCV, weight loss, lethargy, weakness and dullness. The reaction time of semen collection significantly increased from a pre-infection mean value of 24·3–60·13 seconds to a mean of 14·25–267·25 seconds 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 abnormal sperm cells. By the sixth week, the 16 infected bulls were unfit for breeding because of very poor semen characteristics. Deterioration continued to the end of the investigation. The present results indicate that T. congolense appeared more virulent and devastating in its effect on the reaction time (ejaculation time) and on the destruction of germinal epithelium which resulted in poor semen quality. This is of particular significance to livestock farmers in trypanosome endemic regions, the practical implication being infertility in infected bulls.

The variations with age in serum iron concentration and iron-binding capacity in zebu cattle were investigated. Serum iron concentration was lower in calves from birth to four weeks of age than in older cattle. Total iron-binding capacity decreased while percentage saturation increased with advancing age.