The effect of two levels of dietary protein on resistance and resilience of dairy goats experimentally infected with Trichostrongylus colubriformis: comparison between high and low producers

Numerous studies have examined the interactions between protein nutrition a nd the response to nematode parasitism in sheep, but very few in goats. Com pared with other ruminants, goats are less resistant to nematode infection. In addition, in dairy goats, high producing animals have been shown to be less resistant and less resilient to infection compared to low producing on es. The objective of the present study was to examine the consequences of p rotein supplementation on both resistance and resilience of daily goats to nematode trickle infection, taking into account the initial level of milk p roduction of the animals. During a 14-week period, 40 milking goats receive d a high protein (HP) diet supplying 130% of the protein requirements, and 38 goats were fed a intermediate protein (IP) diet (120% of the protein req uirements). In addition, half of each group was given a weekly trickle infe ction with Trichostrongylus colubriformis larvae, the other part of the flo ck remained non-infected. Faecal egg counts (FEC), eosinophil counts and pa thophysiological data (urea, albumin and inorganic phosphate concentrations in the serum) were measured twice a month. Milk production data (milk yiel d, protein and fat contents) were also recorded every 15 days. The results showed that FECs were lower (p < 0.05) and eosinophil counts higher (p < 0. 05) in the animals receiving the HP dirt suggesting that resistance was enh anced by protein supplementation. Meanwhile, milk parameters (related to re silience) were not affected by the level of protein in the diet when consid ering the whole groups. In contrast, in the high producing goats, the milk production and milk composition parameters were improved with the HP diet. To conclude, we have seen that the expression of both resistance and resili ence did not appear when the coverage of the protein requirements was insuf ficient. Because the milk production is dependent on the protein supply, we suggest that there it: a competition in the use of the protein between the development of resistance and the milk production.