Comparing the phenotypic susceptibility of Pelibuey and Katahdin female lambs against natural gastrointestinal nematode infections under hot humid tropical conditions

Abstract

This study compared the phenotypic susceptibility of Pelibuey and Katahdin female lambs against gastrointestinal nematodes (GINs) under grazing conditions in the hot humid tropics of Mexico. The study was performed during the rainy season (August to October, 2014). It included 27 Pelibuey and 12 Katahdin female lambs from 6 months of age and live weight of 21.0 ± 3.7 and 23.3 ± 3.6 kg, respectively. Lambs were reared free of GIN infection before the study. The study lasted 91 days. Animals were weighed and sampled (blood and feces) on days 0 and 28 and every 7 days onwards. Fecal samples were obtained to determine fecal eggs of GIN per gram (EPG), and blood samples were used to determine the packed cell volume (PCV), the peripheral eosinophil counts (PECs), and optical densities (ODs) for IgA. The EPG counts were significantly lower for Pelibuey lambs compared to Katahdin throughout the study (P < 0.001). Similarly, Pelibuey lambs had higher mean PCV (P < 0.01) and PEC (P < 0.05) than Katahdin lambs during the study. The total weight gain and OD for IgA were similar between breeds (P > 0.05). Negative associations (P < 0.05) between EPG and PCV or PEC were moderate to strong for the lambs of both breeds. No association was found between EPG and IgA. In conclusion, Pelibuey lambs showed phenotypic evidence of higher resistance to natural GIN infections compared to Katahdin lambs sharing the same grazing conditions in the hot humid tropics. The most accurate phenotypic markers to identify a difference in susceptibility were EPG and PEC.

Genetic parameters for fecal egg counts and their relationship with body weights in Katahdin lambs

“…Hair sheep breeds have been reported to be more resistant to parasite infection than wool breeds (Courtney et al, 1985;Zajac et al, 1990; Burke and Miller, 2004;Vanimisetti et al, 2004b). The Katahdin, a composite breed developed from crosses between temperate wool and Caribbean hair breeds, has also been shown to have greater parasite resistance than wool breeds but to be less parasite resistant than Caribbean hair sheep breeds (Vanimisetti et al, 2004b;Palomo-Couoh et al, 2017). The NSIP Katahdin breeders measure FEC in lambs at weaning (between 45 and 90 d of age) and postweaning (usually between 90 and 150 d of age but occasionally up to 240 d of age) to assess variations in innate and acquired resistance to parasites (Notter, 2013).…”

Identification of somatic proteins in Haemonchus contortus infective larvae (L3) and adults

“…Somatic proteins such as HC23 and their recombinant version (rHC23), rHcp26/23 and recombinant galectin (rHco-gal-m and rHco-gal-f) have been used for inducing partial protection against of H. contortus infection (Yanming et al, 2007;García-Coiradas et al, 2010;González-Sánchez et al, 2018). In the same way, a potential use of H. contortus somatic proteins could be to generate immunodiagnostic antigens to identify early and late H. contortus infections in sheep, similar to the reported in goats (Naqvi et al, 2020), or as an alternative method to identify specific antibodies of resistant sheep that contribute with the traditional method of faecal egg count (FEC) to identify resistant animals (Palomo-Couoh et al, 2016;Palomo-Couoh et al, 2017;Cruz-Tamayo et al, 2020). In this study, we report a list of somatic proteins of H. contortus and a comparative analysis between somatic proteins from L 3 and adult parasites recovered from an infected lamb.…”

“…Since anthelmintic resistance has been described in several spe-cies of parasites (Pandey and Sivaraj, 1994;De Albuquerque et al, 2017), new strategies to control the infections and their adverse effects have been developed. Among these, the selection of animals with resistance to GI parasites has been in the spotlight (Palomo-Couoh et al, 2017;Aguerre et al, 2018;Estrada-Reyes et al, 2019;Zaragoza-Vera et al, 2019 ). Thus, the study of protein molecules (involved mainly in secretion-excretion) focused on the parasite-host interactions and the identifi cation of targets to elaborate new drugs or vaccines (Gadahi et al, 2016;Wang et al, 2019a).…”

Physiological, immunological and genetic factors in the resistance and susceptibility to gastrointestinal nematodes of sheep in the peripartum period: A review

“…The resistance of some genotypes depends largely on conditions of environmental origin (Alba-Hurtado & Muñoz-Guzmán, 2013) and flock management. Generally, native genotypes such as Red Maasai (Wanyangu et al, 1997), Santa Inés (Rocha et al, 2004;Albuquerque et al, 2019), Crioula Lanada (Bricarello et al, 2004, Barbados Blackbelly (Yazwinski et al, 1981;Zaragoza-Vera et al, 2019), Florida Native (Courtney et al, 1984, 1986Díaz-Rivera et al, 2000), Castellana (Gómez-Muñoz et al, 1999), Pelibuey (Morteo-Gómez et al, 2004;Palomo-Couoh et al, 2017), and Mexican creole (Alba-Hurtado et al, 2010) are more resistant to H. contortus. Native genotypes, which for many years have thrived in unfavourable environments with poor zootechnical management and without exposure to anthelmintic treatments have proven to be more resistant (Alba-Hurtado & Muñoz-Guzmán, 2013).…”