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The present study aimed to evaluate the effects of Trypanosoma vivax infection on the shape of the lactation curve and the milk quality of dairy goats experimentally infected with T. vivax. In total, twenty Saanen goats, aged 26-30 months and the same number of calving (two calvings), were divided into two experimental groups: an infected group, consisting of ten goats intravenously infected with 0.5 ml of blood containing approximately 1.25 × 10(5) trypomastigotes of T. vivax and ten uninfected animals as the control group. Clinical tests and hematocrit, parasitemia, and serum biochemistry evaluations were performed on all of the goats. Milk production was measured daily for 152 days by hand milking the goats and weighing the milk. Every seven days, physiochemical analyses were performed to evaluate the milk. Wood's nonlinear model was used to analyze the lactation curve parameters. The infected goats had high levels of parasitemia and hyperthermia, significantly reduced hematocrit, serum total protein, albumin, and glucose levels and increased cholesterol and urea concentrations. Wood's model indicated that the milk production of goats in the infected group declined sharply over a short period of time and produced a flattened yield curve and significant difference (P < 0.05) in the rate of increase of peak milk production, rate of decrease of milk production after the peak, day of peak milk production, and maximum peak milk production compared with that of the control group. Trypanosomiasis also affected the persistency of lactation, which was significantly reduced in goats in the infected group. In addition, the physico-chemical properties of the milk, including the fat content, defatted dry extracts (DDE) and protein content, decreased significantly (P < 0.05) in the goats in the infected group compared with those in the control group. The T. vivax-infected goats showed reduction in milk production, persistence of lactation, and fat levels, the defatted dry extract (DDE) content, and protein, changing the quality of milk., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Thirty-six West African Dwarf (WAD) goats were used to assess the effects of an experimental Trypanosoma congolense infection on their reproductive system. Estrous cycles were synchronised and when confirmed pregnant (n = 31), the does were randomly allocated into control and trypanosome-infected groups. After infection, the animals were carefully observed till parturition. Trypanosome infection caused an increase of rectal temperature, a significant drop in PCV (infected: 23.3 +/- 0.3%; control: 28.5 +/- 0.4%; P < 0.0001) and abortions in 27.8% of the infected does. Kids born from infected does had a lower birth weight than kids born from control goats (0.9 +/- 0.1 kg versus 1.6 +/- 0.1 kg; P < 0.0001). Eight out of 13 kids (61.5%) that were born alive from infected does died during their first week of life. Plasma pregnancy-associated glycoprotein (PAG) and progesterone concentrations were lower in the infected animals than in the controls. In general, PAG concentration in does which aborted dropped before abortion. Our results revealed that artificial T. congolense infection affected reproductive performance of WAD goats with abortions, premature births and perinatal losses being observed. Neither transplacental transmission of T. congolense nor histopathological lesions of the placenta could be demonstrated.

Ten West African Dwarf (WAD) does and 12 Djallonké ewes were artificially infected with a West African strain of Trypanosoma congolense and observed over two years. The infected animals showed a chronic anaemia together with a persistent parasitaemia but very low mortality and increase in body weights was not significantly different from the control. In the infected sheep significant differences were found in offspring production at three and five months due to a higher mortality among the lambs. The infected goats had more abortions and stillbirths and period to first kidding, total number of parturitions, production at birth, one, three and five months were significantly different from the controls. A productivity index was calculated and revealed that a chronic T congolense infection significantly decreases the productivity of WAD goats during two years whereas in Djallonké sheep, the loss in productivity is recovered after one year. Although both species are regarded as trypanotolerant, the Djallonké sheep show a better tolerance to a chronic T congolense infection that the WAD goats.

The present study investigated the influence of supplementation with cotton seed cake on the resistance of the Small East African breed of goats to primary and secondary challenges with Trypanosoma congolense and on their response to chemotherapy with diminazene aceturate. The supplemented group received 300 g of cotton seed cake per day in addition to about 500 g of fresh napier grass which was available to the unsupplemented group. It was observed that the supplemented infected (SI) group tended to sustain higher intensities of parasitaemia than the unsupplemented infected (USI) group particularly during the primary challenge and both groups showed longer prepatent periods to secondary challenge than to primary challenge. Infection caused a significant reduction in the rate of live body weight gain in the USI group compared with the unsupplemented control (USC) group whilst the SI group grew at the same rate as the supplemented control (SC) group. This effect was observed both during primary and secondary challenges. Following primary challenge, both infected groups developed similar degrees of anaemia, but the packed red cell volume (PCV) levels in the SI group improved towards the end of the first challenge and were also significantly higher than those of the USI group during the second challenge. After treatments at 56 and 126 days after infection (DAI), the greatest response was observed in PCV values. The response of the SI group was superior to that of the USI group and by 4 weeks after treatment the PCV values of the SI and SC groups were similar while those of the USI group were significantly lower than those of the USC group. It is concluded that supplementation with cotton seed cake plays an important role in the rate of live weight gain, and rate of recovery from anaemia produced by trypanosome infection in goats.

The relationships between heat production, body temperature, and body posture (standing/lying) were studied in goats suffering from trypanosomiasis. Sixteen goats were selected and infected with 1 x 10(6) Trypanosoma vivax parasites and 8 goats served as controls. In week 2, 4, and 6 after infection heat production, body posture, and body temperature were measured at 15-minute intervals. Heat production was higher (P < 0.01) in infected animals compared with control animals (342, respectively 306 kJ.kg- 0.75.d-1), body temperature was also higher (P < 0.001) in infected goats (39.78 degrees C, respectively 38.51 degrees C). The standing related energy costs per day were lower in infected animals (27 respectively 36 kJ.kg-0.75.d-1). Infected animals, therefore, masked part of the energy costs of infection by reducing the standing time. The heat production of infected animals was increased by 21 kJ.kg-0.75.d-1 per 1 degree C fever (7% increase). During periods of standing, body temperature increased with time, whereas during lying periods, it decreased. The number of standing periods was increased in infected animals. It was discussed whether postural behaviour is influenced by thermoregulatory mechanisms.

Twenty-three mature dwarf goats were used to study whether there is a relationship between the decrease in feed intake for individual goats and infection with T.congolense and T. vivax. Furthermore, it was investigated how rectal temperatures and blood parameters were affected by the T. congolense infection and how changes in these parameters can be used to predict the effect of a T. vivax infection on feed intake. For individual goats a ranking correlation was found between relative dry matter intake and infection (r = 0.59; p < .05). Animals with the most marked decrease in dry matter intake during the T. congolense infection showed a smaller increase in urea and a higher increase in non esterified fatty acids and beta-hydroxy butyrate levels in their blood. Evidence was obtained that the relative decrease in dry matter intake for individual goats during a T. vivax infection can be predicted on the basis of urea and creatinine responses measured in the blood during a previous infection with T. congolense infection.

Thirty-two mature dwarf goats weighing between 16 and 30 kg (22.7 +/- 3.7, SD) were used to study the effect of Trypanosoma vivax infection on rectal temperature (RT), feed intake (DMI), and metabolic rate. Sixteen of the goats were infected intravenously with 14 X 10(6) T. vivax each; the 16 others served as controls. Animals were fed at about 1.1 times maintenance. Heat production was measured from 1 wk preinfection to 6 wk postinfection. From data on successive 9-min periods, heat production was calculated per 24-h period and separately for 0700 to 2000 (day period) and for 2000 to 0700 (night period). Rectal temperature was measured twice weekly. Compared with controls, animals infected with T. vivax developed and maintained a 1 degree C higher RT and a higher metabolic rate. After the prepatent period of 5 to 7 d, during which RT remained normal, all infected goats had a period of about 7 d with constant high temperatures. After that initial episode, RT fluctuated. Heat production of infected animals was increased by 15.6 kcal.d-1.kg-.75, or about 16%. This increase in heat production was greater during the night (22 kcal.d-1.kg-.75) than during the day (14 kcal.d-1.kg-.75). After T. vivax infection, large differences in DMI among animals were apparent. In four animals, a clear relation between DMI and RT was noted, but in 12 animals no such relationship was apparent.

The effects on the fertility of small East African male goats of intravenous infection with Trypanosoma (t) (b) evansi were studied. Six infected bucks developed erratic, low but persistent parasitaemia, the packed cell volume dropped gradually but significantly (p less than 0.001) and they became emanciated. Half of these bucks developed clinical orchitis. Two bucks died of the disease during the experiment. Semen from all the infected bucks deteriorated in quality and quantity and those with clinical orchitis became totally aspermic. Spermatozoal abnormalities and the number of dead spermatozoa rose significantly. Later in the disease, the testicles of the infected bucks atrophied. Histologically, the testicles from the infected animals became devoid of spermatozoa, the testicular blood vessels contained microthrombi and there was infiltration of inflammatory cells. Subsequently, diffuse calcification set in, with calcium deposits obliterating most of the seminiferous vesicles and ducts and also the epididymal ducts.