Phenotypic and genetic parameters of reproductive traits in Tunisian Holstein cows

Abstract

Various factors influencing reproduction in dairy Holstein cows were routinely evaluated and genetic parameters were estimated for four traits to assess fertility of artificially inseminated cows: Calving to first service interval (CFSI), calving interval (CI), calving to conception interval (CCI) and number of services per conception (NSC). Data used in this investigation consisted of records of insemination and calving events on Tunisian Holstein cows. The data included records from 1994 to 2003 in 150 herds. The aim of the study was to investigate the effects of non-genetic factors on reproductive traits and estimate their heritabilities. The factors examined were: month and year of calving, herd, parity, and year-month of calving. The effect of month and year of calving (or insemination), herd, parity and year-month of calving were included in the model and were significant (P < 0.01) except for the number of lactations that does not have an effect on the NSC. A decreasing efficiency in cow fertility was observed over the last years, with a longer day for first service interval. Heritability for fertility traits was low ranging from 0.027 for NSC to 0.067 for CI. The results suggested that more attention should be paid to herds with too low fertility traits and that monitoring and intervention schemes should be tested in research approaches.Key words: fertility traits, genetic parameters, non-genetic factors, Tunisian Holstein RESUMEN Se evaluaron de manera rutinaria diferentes factores que influyen en la reproducción de las vacas lecheras Holstein y se estimaron los parámetros genéticos de cuatro caracteres para evaluar la fertilidad de las vacas inseminadas artificialmente: el intervalo de parto a primer servicio (IPPS), el intervalo entre partos (IP), el intervalo de parto a concepción (IPC) y el número de servicios por concepción (NSC). Los datos utilizados en esta investigación consistieron de registros de eventos de inseminación y partos en vacas Holstein de Túnez. Los registros fueron tomados desde 1994 hasta 2003 en 150 rebaños para estudiar los efectos de factores no genéticos y estimar las heredabilidades de los caracteres anteriormene señalados de fertilidad. Los factores examinados fueron: mes y año de parto, rebaño, paridad y año-mes de parto. El efecto del mes y año de parto (o inseminación), rebaño, paridad y año-mes de parto se incluyeron en el modelo y fueron significativos (P <0,01) con excepción del número de lactancias que no tiene un efecto sobre el NSC. Se observe una eficiencia decreciente en la fertilidad de las vacas en los últimos años, con un día más largo para el intervalo del primer servicio. La heredabilidad para los caracteres de la fertilidad fue baja en un rango de 0,027 para NSC a 0,067 para el interval entre partos. Los resultados sugieren que debería prestarse más atención a los rebaños con rasgos muy bajos de fertilidad y que los esquemas de vigilancia e intervención deberían ser evaluados con enfoques de investigación, Palabras clave: Caracteres de fertilidad, pa...

Genetic and environmental variance and covariance parameters for some reproductive traits of Holstein and Jersey cattle in Antioquia (Colombia)

“…As for DO, the heritability estimates obtained in this study were 0.082 and 0.090 for Holstein and Jersey cattle, respectively; this is consistent with the results reported by Pantelic et al (2011) and Ghiasi et al (2011). In contrast, some authors report very low heritability values (Estrada-León et al, 2008;M'hamdi et al, 2010;Ríos-Ultrera et al, 2010a).…”

“…These values were higher than those reported by Ojango and Pollott (2001) and Kadarmideen et al (2000). Nevertheless, some authors (Estrada-León et al, 2008;M'hamdi et al, 2010;Ríos-Ultrera et al, 2010a) report higher repeatability values (0.120-0.180). Regarding DO, the repeatability values obtained in both breeds The correlations between CI and DO in this study for Holstein and Jersey cattle were 0.98 and 1.00, respectively.…”

<b>Genetic analysis of fertility traits of Holstein dairy cattle in warm and temperate climate

“…Regarding CI, the repeatability value obtained (0.057) was nearly the same as reported by Ojango and Pollott (2001) (0.06). Nevertheless, Kadarmideen, Thompson, and Simm (2000) obtained lower value (0.049) and some authors (Estrada-León, Magana, & Segura-Correa, 2008;M'hamdi et al, 2010; Ríos-Ultrera, Calderón-Robles, Rosete-Fernández, & Lagunes-Lagunes, 2010a) report higher repeatability values (0.120-0.180). Repeatability for GL was estimated to be 0.181, which was lower than estimated repeatability by Johanson et al (2011) (0.54).…”

Genetic parameters of reproductive traits in Tunisian Holsteins

“…Genetic and environmental factors included in the model were designed to reflect data structure and were as inferred from the literature reporting on reproduction data analyses (Muir et al, 2004;Sewalem et al, 2010;Ghiasi et al, 2011, M'Hamdi et al, 2011. Data were analyzed with a five-trait animal model.…”

“…Estimates of genetic parameters for milk, fat, and protein yields from Tunisian data are reported in several publications (Ben Gara et al, 2006;Hammami et al, 2007Hammami et al, , 2008. However, genetic parameters for fertility traits were rarely investigated (M'Hamdi et al, 2011). Most of the culling has consistently been explained with unsatisfactory fertility performances.…”