Genetic and phenotypic parameters and annual trends for growth and fertility traits of Charolais and Hereford beef cattle breeds in Kenya

Calving records from the Animal Breeding Center of Iran collected from January 1990 to December 2007 and comprising 207,106 first calving events of Holsteins from 2,506 herds were analysed using univariate and bivariate linear sire models to estimate heritabilities and genetic correlations between age at first calving (AFC) and productive performance. Average AFC was 26.48 months in this study. The peak in the frequency distribution of AFC clearly exists coinciding with cows calving for the first time at approximately 25 months of age. Heritability estimate for AFC was 0.34 which was greater than the corresponding values for productive traits. The heritability estimates were low to medium for productive traits which ranged from 0.17 to 0.26 for cows in their first calvings. Except for fat and protein percentages of milk, phenotypic and genetic correlations between AFC and productive performance traits were low to moderately negative. Range of genetic correlations between productive traits was -0.53 to 0.99. Reduction of age at first calving appeared to have a negative effect on first lactation protein and fat percentages; however, it had positive effects on milk yield, fat yield, protein yield and their mature equivalents. It seems that reducing age at first calving to 24-25 months is probably more profitable than reducing age at first calving to an earlier time in Iranian conditions.

Section: Discussionsupporting

confidence: 79%

Estimation of genetic and phenotypic relationships between age at first calving and productive performance in Iranian Holsteins

Hossein-Zadeh

2011

“…Khan et al 1999;Maiwashe et al 2002;Wasike et al 2009). However, positive correlations of 0.47 and 1.00 for BW were reported for Zebu crossbreds in Ethiopia (Demeke et al 2003) and Hereford calves in Kenya (Orenge et al 2009), respectively. The correlation estimated for WW (−0.65) in this study is lower than the estimate of −0.25 reported by Wasike et al (2009) Maiwashe et al (2002) reported an estimate of −0.54 for WW in Bonsmara cattle in South Africa.…”

Section: Resultsmentioning

confidence: 97%

“…In a study on Boran cattle in Kenya, Wasike et al (2009) reported low maternal environmental variance at birth (c 2 =0.16); however, unlike in our study and those mentioned, maternal environmental effects played a great role accounting for a significant variation in pre-weaning growth. The relatively large phenotypic variances for pre-weaning growth performance in tropical cattle breeds under the cow-calf feeding system is a reflection of differences in individual dam's milk production and mothering ability (Orenge et al 2009;Wasike et al 2009), compared to artificial feeding systems where calves are subjected to relatively uniform feeding regimes (e.g. Khan et al 1999;Demeke et al 2003).…”

Section: Resultsmentioning

confidence: 99%

“…Wasike et al (2009) recommended the introduction of heifers in the bullying herds on weight rather than age criteria given the negative correlation between AFC and WW they reported in the Boran beef cattle. Orenge et al (2009) also reported low and negative genetic and phenotypic correlations in Hereford beef cattle population where service age was mainly influenced by heifer's age rather than weight. However in this study (Orenge et al 2009), a unit genetic correlation and 0.11 phenotypic correlations were reported for Charolais beef breed.…”

Section: Genetic and Phenotypic Correlationsmentioning

confidence: 93%

“…Orenge et al (2009) also reported low and negative genetic and phenotypic correlations in Hereford beef cattle population where service age was mainly influenced by heifer's age rather than weight. However in this study (Orenge et al 2009), a unit genetic correlation and 0.11 phenotypic correlations were reported for Charolais beef breed. Genetic and phenotypic correlation between growth traits and milk yield were generally low and positive (ranged from 0.11 to 0.34 and 0.09 to 0.31, respectively, see Table 4).…”

Section: Genetic and Phenotypic Correlationsmentioning

confidence: 93%

See 2 more Smart Citations

Sahiwal cattle in semi-arid Kenya: genetic aspects of growth and survival traits and their relationship to milk production and fertility

Ilatsia

Migose

Muhuyi

et al. 2011

Self Cite

The aim of this study was to estimate genetic and phenotypic parameters for growth and survival traits of Sahiwal cattle in Kenya and determine their relationship to milk production and fertility. Performance records of 5,681 animals were obtained from the National Sahiwal Stud and the traits considered were: birth weight (kilogrammes), weaning weight (kilogrammes), pre-weaning average daily gain (grammes per day), post-weaning average daily gain (grammes per day), yearling weight (kilogrammes), mature weight at 36 months (kilogrammes), pre-weaning survival rate (SR), post-weaning survival rate (PSR), lactation milk yield (kilogrammes), age at first calving (days), and calving interval (days). The data was analysed using univariate and bivariate animal model based on restricted maximum likelihood methods, incorporating all known pedigree relationship among animals. The additive direct effects were more pronounced than maternal genetic effects in early and in post-yearling growth performance. The additive genetic variance and heritabilities were low for SR and PSR. The correlation between direct additive genetic and maternal genetic effect were negative for pre-yearling traits. Genetic and phenotypic correlations among growth traits and between growth and milk yield were positive, whilst those between growth and fertility were weak and negative. Correlations between survival and growth were generally low and positive. The estimates obtained in this study provide the necessary technical parameters for evaluating alternative breeding programmes and selection schemes for sustainable improvement of Sahiwal cattle.

Estimates of phenotypic and genetic parameters for birth weight of Brown Swiss calves in Turkey using an animal model

Şahin

Ulutaş

Adkinson

et al. 2011

A study was conducted to assess the influence of genetic and environmental factors on Brown Swiss calf birth weight, and to estimate variance components, genetic parameters, and breeding values. Data were collected on 1,761 Brown Swiss calves born from 1990 to 2005 in the Konuklar State Farm in Turkey. Mean birth weight for all calves was 39.3 ± 0.09 kg. Least squares mean birth weights for male and female Brown Swiss calves were 40.3 ± 0.02 and 39.0 ± 0.02 kg, respectively. Variance components, genetic parameters, and breeding values for birth weight in Brown Swiss calves were estimated by restricted error maximum likelihood (REML)-best linear unbiased prediction(BLUP) procedures using an MTDFREML (multiple trait derivative free restricted maximum likelihood) program employing an animal model. Direct heritability (h(d)(2)), maternal heritability (h(m)(2)), total heritability (h(T)(2)), r(am) and c(am) estimates were 0.12, 0.09, 0.23, -0.58, and -0.06, respectively. The estimated maternal permanent environmental variance expressed as a proportion of the phenotypic variance (c(2)) was 0.05. Breeding values were estimated for the trait and used to evaluate genetic trends across the time period investigated. The genetic trend linear regression was not different from zero. No genetic trend for birth weight was expected, since there had been no direct selection pressure on the trait. Absence of a trend confirms that there was no change due to selection pressure on correlated traits. Genetic and environmental parameter estimates were similar to literature values indicating that effective selection methods used in more developed improvement programs would be effective in Turkey as well.