Resumen

AGUIRRE-VALVERDE, Judyana; VARGAS-LEITON, Bernardo  y  ROMERO-ZUNIGA, Juan José. Efecto de la endogamia sobre parámetros productivos en vacas Holstein y Jersey de Costa Rica. Agron. Costarricense [online]. 2013, vol.37, n.2, pp.31-44. ISSN 0377-9424.

Effect of inbreeding on productive parameters in Costa Rican Holstein and Jersey cows. A retrospective longitudinal study was conducted with 208 148 records of Holstein and Jersey cows from 545 specialized dairy herds present in the VAMPP Bovino National Data Base, of the Regional Center of Informatics for Sustainable Animal Production (CRIPAS), School of Veterinary Medicine, National University, from  1995  to  2010.  The  effect  of  inbreeding on the 305-day-corrected milk yield (PC305d) and productive life--calculated according to the USDA formula--, was analyzed by multiple linear regression, using a mixed model. A cut-off point value of ≥6.25% for the coefficient of inbreeding (F) was used to delimit high F levels. In addition, the possibility for a cow with F≥6.25% having low  productive  parameters  was  calculated  by non conditional logistic regression. The survival analysis,  using  the  Weibull  distribution,  was used to determine the effect of inbreeding on the productive life. A 17.9% of animals with inbreeding was found, being Holstein the race with more inbred cows, although Jersey had, on the average, the highest inbreeding levels. Cow with low F produced +140.4 kg PC305d compared to those having elevated F levels (p<0.01). Cows with high F had increased risk of PC305d <5000 kg (Jersey) and <6500 kg (Holstein) than those with low inbreeding coefficient (OR=1.3; IC95%: 1.2-1.4). It was observed, +10.3 months and +19.3 months of productive life (USDA) for Holstein and Jersey cows with low inbreeding coefficient. We conclude that there is a negative effect of elevated inbreeding coefficient on the productive life (USDA) and the PC305d of Holstein and Jersey cows in Costa Rican dairy farms.

Palabras clave : Inbreeding; 305 day milk yield; dairy cattle; Costa Rica.

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