Losses caused by gastrointestinal nematode infections in Dorper lambs under two nutritional status

Abstract

The aim of this study was to evaluate the effect of two nutritional statuses on the productive performance of Dorper lambs naturally infected with gastrointestinal nematodes. Thirty-two lambs, grazing together on the same pasture, were allocated into four experimental groups: (G1) infected-supplemented diet, (G2) control-supplemented diet, (G3) infected-basal diet, and (G4) control-basal diet. Control animals received suppressive treatment with monepantel every two weeks, while precautionary anthelmintic treatments were given to all lambs of the infected groups with packed cell volume (PCV) <23%. There was reduction in the PCV means of all groups, which was more pronounced in the infected lambs that also presented reduction in total plasma protein values in comparison with the controls. Weight gain was affected by diet and infection status (P < 0.05). Daily body weight gain was 0.170 kg in the G1, 0.205 kg in the G2, 0.085 kg in the G3, and 0.116 kg in the G4. The cold carcass weight was 4.1% and 13.7% higher in controls in comparison with infected lambs, respectively, in the supplemented and basal diets. The infected groups, despite receiving precautionary anthelmintic treatments to prevent deaths due to haemonchosis, presented reduction in the production parameters in comparison with the controls.

Performance of lambs under four levels of dietary supplementation and artificially mix-infected with Haemonchus contortus and Trichostrongylus colubriformis

“…These results are in agreement with reports from studies carried out on lambs experimentally infected with H. contortus, in which increased resilience was seen among the supplemented animals (Wallace et al, 1995;Bricarello et al, 2005;Carvalho et al, 2015). In field studies conducted in Brazil on young lambs, benefits from supplementation have also been demonstrated: the animals became more resistant/resilient to natural infections with GINs, with increased productive performance (Louvandini et al, 2006;Melo et al, 2017;Starling et al, 2019).…”

“…In a study on grazing Dorper lambs that were naturally infected with GINs and subjected to two nutritional statuses, it was demonstrated that supplemented lambs that underwent suppressive treatment with an anthelmintic (control group) showed a daily body weight gain 17.1% higher than that of the infected group counterpart that underwent targeted selective treatment with an anthelmintic. Among the lambs that received the baseline diet, the difference between the infected and control groups was the largest, at 26.7% (Starling et al, 2019).…”

“…Therefore, as a continuation of the study on Dorper lambs (Starling et al, 2019), the present experiment was carried out with the aim of determining, under controlled conditions of infection and nutrition, what influence four levels of dietary supplementation would have on the performance of Dorper lambs that were serially infected with H. contortus and T. colubriformis.…”

Comparative study on pathological changes in sheep and goats experimentally infected with Haemonchus Contortus

“…Body weight reduction was more marked in goats and can be related to the reduced appetite, loss of serum protein and digestion problems linked to disturbances in gastric secretion (Fox 1997). Similar reduction in body weights have been documented by previous studies in sheep and/goat (Kelkele et al 2012;Starling et al 2019).…”

Prophylactic Effects of Ivermectin and Closantel Treatment in the Control of Oestrus ovis Infestation in Sheep

“…Also drew attention the fact that the treatment against oestrosis did not influence the weight gain of the animals, demonstrating the benign character of the disease in lambs. The treatment with anthelminthics, including in those lambs from control group, avoided the interference of helminthiasis in the body weight gain of the lambs, which were around 190 g per day, within the expected for grass fed male lambs supplemented with concentrate ( 30 ). However, more studies are necessary to evaluate the influence of oestrosis on sheep productivity in our environmental conditions, especially in older animals continuously exposed to the parasitism.…”