Gastrointestinal nematode infection in Purunã heifers raised in conventional and integrated livestock forest systems

Barbara Haline Buss Baiak,Jennifer Mayara Gasparina,José Luis Moletta,Raquel Abdallah Da Rocha

doi:10.1590/s1519-99402121152020

Abstract

ABSTRACT The objective of the study was to evaluate the resistance of Purunã heifers to nematode infection in two different production systems. In this study, 29 heifers were divided into eight pickets, four in an integrated livestock forest system (ILF) and four in a conventional pasture system (CPS). Feces were collected monthly to perform the fecal egg count (FEC), evaluate the degree of infection caused by gastrointestinal nematodes in cattle, and carry out coproculture, to identify the genus of the parasites. In addition, animal body weight was determined to evaluate performance. On the same day as the measurements, forage samples were collected to determine the number of infective larvae per kilogram of dry matter (L3/kg DM) in each picket. There were no statistical differences in FECs between the treatments. Although no significant differences were observed in the recovery of L3/kg DM, the contamination was higher in the ILF compared to CPS in December (344 and 37.7 L3/kg DM, respectively) and January (312 and 0 L3/kg DM, respectively). In March, the CPS (321 L3/kg DM) presented higher contamination than the ILF (80.7 L3/kg DM), but with no statistical difference. The weight of the animals was higher for the CPS compared to the ILF treatment throughout the whole experimental period, with a significant difference in December (343.30 kg and 314.08 kg, respectively). The present study demonstrated numerically that greater numbers of L3 were recovered from pasture of the ILF, which could have resulted in higher contamination and lower performance of the animals.

Highlights

Pastures are the most economical source of nutrients for cattle
The L3 counts from the pastures (Figure 2) were higher in December (344 L3/kg dry matter (DM)) and January (312 L3/kg DM) for integrated livestock forest system (ILF) compared to conventional pasture system (CPS) (37.7 and 0 L3/kg DM, respectively)
The coprocultures of the animals kept in different production systems predominantly identified the gastrointestinal nematode Haemonchus spp. (67.75%ILF and 70.53% CPS), followed by Trichostrongylus spp

Summary

Introduction

Pastures are the most economical source of nutrients for cattle. In this ecosystem, the infections caused by gastrointestinal nematodes are considered a sanitary problem (Amarante, 2011). Even though the signs are often subclinical, parasites cause metabolic alterations, with consequent decreases in host performance. Intensity varies with animal age and, especially, with the production system (Stromberg et al 2012). Cattle production can be managed in either conventional or integrated systems. The latter includes the tree component, in which animals benefit from thermal comfort and greater moisture. Adequate environmental conditions such as humidity, luminosity, and temperature, foster the development of infective larvae (L3) (Quadros et al 2010).

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Conclusion