Abstract

AGUIRRE-VALVERDE, Judyana; VARGAS-LEITON, Bernardo  and  ROMERO-ZUNIGA, Juan José. Efectos de la endogamia sobre parámetros Reproductivos en vacas holstein y jersey de Costa Rica. Agron. Mesoam [online]. 2013, vol.24, n.2, pp.245-255. ISSN 2215-3608.

Effects of inbreeding on reproductive parameters of Costa Rican Holstein and Jersey cows. The objective of this study was to analyze the effect of high inbreeding (F) levels (≥ 6.25%) on reproductive parameters of Holstein and Jersey cows born between Jan 1995 and Dec 2010 in specialized dairy herds in Costa Rica. Data on age at first calving (AFC), open days (DO) and services per conception (SPC) from (n=263 804) from the VAMPP national data base, at the Veterinary School of the Universidad Nacional, was used. An F value ≥ 6.25% (high/risk) was used as a cut-off point. The data were processed using descriptive statistics, multiple linear regression (mixed model), and logistic regression. A 17.9% of animals had some inbreeding, with an F average of 0.42% (0.49% and 0.55% for Holstein and Jersey). 22.6% of Holstein and 20.3% of Jersey were inbreed; however, in Jersey, there were cows with higher F. Cows with some inbreeding have an average F of 2.16% for Holstein and 2.98% for Jersey. Furthermore, cows with low F had 18 d less of AFC (p<0.01) compared to those with high F. Regarding the DO, there were +0.53 d for animals with low F (P= 0.71); while the cows with low F had +0.08 SPC (P<0.01). There was no risk of DO or SPC in animals with F ≥ 6.25%; which occurred for AFC (OR = 1.23; 95% CI: 1.10-1.38). According to this study, inbreeding did not affect the DO, but slightly affects the SPC and the AFC in Holstein and Jersey cows.

Keywords : inbreeding; age at first calving; services per conception; open days; dairy cattle.

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