Gastrointestinal nematode infection in beef cattle of different genetic groups in Brazil

Abstract

Resistance to natural infection by gastrointestinal nematodes was compared in 67 female calves of the following genetic groups: Nelore (NX); 1/2 Senepol+1/2 Nelore (SN); and 1/2 Aberdeen Angus+1/2 Nelore (AN). The NX (n=26), SN (n=23) and AN (n=18) animals were monitored for 14 months, during which they remained without treatment, allowed to graze in a tropical environment. Eggs per gram of feces (EPG), coprocultures and packed cell volume (PCV) were carried out monthly. No significant effects of the interaction between the genetic groups and month/year of collection and the genetic group on the EPG were found, but there was a significant influence of the month of collection (P<0.01). The monthly PCV measurements did not differ for the animals of the three genetic groups and there was no association found between the EPG and PCV. The animals of the SN and NX groups showed similar numbers of EPG with results zero, while for the AN group these numbers were significantly lower (P<0.05). Although the NX group had a large number of EPG with results zero, it also contained many animals with high counts, meaning this group had higher averages during the entire study period. The following nematode genera were found in the coprocultures: Haemonchus, Cooperia, Oesophagostomum and Trichostrongylus, the latter in smallest proportion. There was no significant difference between the genetic groups for averages of all parasites identified, except Cooperia, which were present in higher numbers in the animals of the NX group (P<0.05). The results obtained in this experiment suggest that the use of Bos taurus x Bos indicus crossbreeds can be a good strategy to reduce the use of chemical control in Brazil.

Weight gain and resistance to gastrointestinal nematode infections in two genetically diverse groups of cattle

“…Although it has been shown that cattle with diverse genetics vary in their susceptibility to GIN (Oliveira et al, 2009(Oliveira et al, , 2013, which could be mediated via immunity to GIN (Forbes et al, 2008) there is little evidence associating the variation in productivity with differences in resistance to GIN. The lack of such evidence hinders the incorporation of such traits in breeding indices in cattle and the use of crossbreeding as means of improving performance and disease resistance into cattle.…”

Gastrointestinal helminths in calves and cows in an organic milk production system

“…However, because of the emergence of resistance and the presence of residues in meat and milk, it has become necessary to develop alternative control methods (OLIVEIRA et al, 2009). Among these methods is the use of parasitological techniques to identify susceptible animals and thus allow selective application of anthelmintics or even replacement of such susceptible animals within a herd (VERCRUYSSE et al, 2009).…”

Short Communication Single nucleotide polymorphisms in candidate genes associated with gastrointestinal nematode infection in goats

“…Two generations of crosses produced 229 F2 animals at Embrapa Caprinos e Ovinos (Sobral, Ceará, Brazil). Samples were obtained to determine the fecal egg count per gram feces according to a previously method described (Oliveira et al, 2009). The data were transformed into log 10 (n + 1), where n is the number of eggs per gram feces, and analyzed using the mixed model procedure of the SAS program (2002/2003).…”