Comparison of two phenotypical methods to segregate resistant and susceptible lambs to parasitic nematodes

Cruz-Tamayo, Alvar; González-Garduño, Roberto; Torres-Hernández, Glafiro; Becerril-Pérez, Carlos M.; Hernández-Mendo, Omar; Ramírez-Bribiesca, Jacinto Efrén; López-Arellano, María E.; Vargas-Magaña, Juan J.; Ojeda-Robertos, Nadia F.

dc.creator	Cruz-Tamayo, Alvar
dc.creator	González-Garduño, Roberto
dc.creator	Torres-Hernández, Glafiro
dc.creator	Becerril-Pérez, Carlos M.
dc.creator	Hernández-Mendo, Omar
dc.creator	Ramírez-Bribiesca, Jacinto Efrén
dc.creator	López-Arellano, María E.
dc.creator	Vargas-Magaña, Juan J.
dc.creator	Ojeda-Robertos, Nadia F.
dc.date	2020-04-28
dc.date.accessioned	2020-07-14T19:03:36Z
dc.date.available	2020-07-14T19:03:36Z
dc.identifier	http://revistas.uach.cl/index.php/australjvs/article/view/6041
dc.identifier	10.4067/S0719-81322020000100103
dc.identifier.uri	https://revistaschilenas.uchile.cl/handle/2250/143655
dc.description	The objective of this study was to compare two segregation methods to select resistant and susceptible female Pelibuey lambs infected naturally with gastrointestinal nematodes (GINs) in relation to their haematological and immunological response. For 6 months, faeces and blood samples were taken fortnightly from 40 grazing 5-month-old female lambs. The lambs were classified according to two methods using faecal egg count (FEC) as a phenotypical trait. In the first (reference) method (M3SE, n = 22), resistant (RES) lambs had FEC lower than the mean – 3 standard errors, the susceptible (SUS) lambs levels higher than + 3 standard errors(n = 10) and the intermediate (INT) lambs (n = 8) were categorised by having FECs between the two values. The second method (QUM) divided the population, using quartiles, into resistant (RES; 25%), intermediate (INT; 50%), and susceptible (SUS; 25%) lambs. The agreement between both methods was estimated using the Kappa index. The packed cell volume (PCV), total plasma protein (TPP) and peripheral eosinophils (EOS) were determined for each group. Serum was used to evaluate the IgA levels. PCV and TPP values were higher (P<0.01) in the RES lambs (31.5 ± 3.4 and 6.16 ± 0.5 g/dL by QUM, respectively, and 31.5 ± 3.9 and 6.24 ± 0.49 g/dL by M3SE, respectively) than the SUS lambs (28.1 ± 4.7 and 5.94 ± 0.5 g/d, respectively, by both methods). The EOS and IgA values increased with age. M3SE and QUM were in moderate agreement (Kappa = 0.43). We concluded that the two segregation methods allowed for the identification of the same female SUS lambs, but a greater number of animals were categorised phenotypically as resistant using the M3SE method. PCV and TPP can help to identify phenotypically resistant animals.	en-US
dc.description	The objective of this study was to compare two segregation methods to select resistant and susceptible female Pelibuey lambs infected naturally with gastrointestinal nematodes (GINs) in relation to their haematological and immunological response. For 6 months, faeces and blood samples were taken fortnightly from 40 grazing 5-month-old female lambs. The lambs were classified according to two methods using faecal egg count (FEC) as a phenotypical trait. In the first (reference) method (M3SE, n = 22), resistant (RES) lambs had FEC lower than the mean – 3 standard errors, the susceptible (SUS) lambs levels higher than + 3 standard errors(n = 10) and the intermediate (INT) lambs (n = 8) were categorised by having FECs between the two values. The second method (QUM) divided the population, using quartiles, into resistant (RES; 25%), intermediate (INT; 50%), and susceptible (SUS; 25%) lambs. The agreement between both methods was estimated using the Kappa index. The packed cell volume (PCV), total plasma protein (TPP) and peripheral eosinophils (EOS) were determined for each group. Serum was used to evaluate the IgA levels. PCV and TPP values were higher (P<0.01) in the RES lambs (31.5 ± 3.4 and 6.16 ± 0.5 g/dL by QUM, respectively, and 31.5 ± 3.9 and 6.24 ± 0.49 g/dL by M3SE, respectively) than the SUS lambs (28.1 ± 4.7 and 5.94 ± 0.5 g/d, respectively, by both methods). The EOS and IgA values increased with age. M3SE and QUM were in moderate agreement (Kappa = 0.43). We concluded that the two segregation methods allowed for the identification of the same female SUS lambs, but a greater number of animals were categorised phenotypically as resistant using the M3SE method. PCV and TPP can help to identify phenotypically resistant animals.	es-ES
dc.format	application/pdf
dc.language	eng
dc.publisher	Facultad de Ciencias Veterinarias - Universidad Austral de Chile	es-ES
dc.relation	http://revistas.uach.cl/index.php/australjvs/article/view/6041/7163
dc.rights	Derechos de autor 2020 Austral Journal of Veterinary Sciences	es-ES
dc.source	Austral Journal of Veterinary Sciences; Vol. 52 Núm. 1 (2020); 9-18	en-US
dc.source	Austral Journal of Veterinary Sciences; Vol. 52 Núm. 1 (2020); 9-18	es-ES
dc.source	0719-8132
dc.source	0719-8000
dc.title	Comparison of two phenotypical methods to segregate resistant and susceptible lambs to parasitic nematodes	en-US
dc.title	Comparison of two phenotypical methods to segregate resistant and susceptible lambs to parasitic nematodes	es-ES
dc.type	info:eu-repo/semantics/article
dc.type	info:eu-repo/semantics/publishedVersion

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