Genetic and phenotypic correlations among feed efficiency, production and selected conformation traits in dairy cows

Abstract

The difficulties and costs of measuring individual feed intake in dairy cattle are the primary factors limiting the genetic study of feed intake and utilisation, and hence the potential of their subsequent industry-wide applications. However, indirect selection based on heritable, easily measurable, and genetically correlated traits, such as conformation traits, may be an alternative approach to improve feed efficiency. The aim of this study was to estimate genetic and phenotypic correlations among feed intake, production, and feed efficiency traits (particularly residual feed intake; RFI) with routinely recorded conformation traits. A total of 496 repeated records from 260 Holstein dairy cows in different lactations (260, 159 and 77 from first, second and third lactation, respectively) were considered in this study. Individual daily feed intake and monthly BW and body condition scores of these animals were recorded from 5 to 305 days in milk within each lactation from June 2007 to July 2013. Milk yield and composition data of all animals within each lactation were retrieved, and the first lactation conformation traits for primiparous animals were extracted from databases. Individual RFI over 301 days was estimated using linear regression of total 301 days actual energy intake on a total of 301 days estimated traits of metabolic BW, milk production energy requirement, and empty BW change. Pair-wise bivariate animal models were used to estimate genetic and phenotypic parameters among the studied traits. Estimated heritabilities of total intake and production traits ranged from 0.27 ± 0.07 for lactation actual energy intake to 0.45 ± 0.08 for average body condition score over 301 days of the lactation period. RFI showed a moderate heritability estimate (0.20 ± 0.03) and non-significant phenotypic and genetic correlations with lactation 3.5 % fat-corrected milk and average BW over lactation. Among the conformation traits, dairy strength, stature, rear attachment width, chest width and pin width had significant (P < 0.05) moderate to strong genetic correlations with RFI. Combinations of these conformation traits could be used as RFI indicators in the dairy genetic improvement programmes to increase the accuracy of the genetic evaluation of feed intake and utilisation included in the index.

Genetic and phenotypic associations of type traits and body condition score with dry matter intake, milk yield, and number of breedings in first lactation Canadian Holstein cows

“…Veerkamp and Brotherstone (1997) observed a genetic correlation of 0.34 between DMI and body depth which is in agreement with the estimate from the current study and slightly lower than the more recent estimates (0.44 and 0.49) by Manafiazar et al (2016) and ManzanillaPech et al (2016), respectively. The genetic correlation between DMI and stature (0.34) observed in the present study was higher than reported by others (Veerkamp and Brotherstone 1997;Parke et al 1999) but comparable to the estimates reported by Manafiazar et al (2016) and Manzanilla-Pech et al (2016). Vallimont et al (2010) also observed positive genetic correlations between stature and intake traits (0.55-0.63).…”

“…Vallimont et al (2010) also observed positive genetic correlations between stature and intake traits (0.55-0.63). Final score, which represents overall conformation score of a cow, had the lowest genetic correlation with intake traits (0.16) in the present study, which is lower than the estimate (0.25) reported by Manafiazar et al (2016). In other words, genetically taller, deeper, and more angular cows could have increased intake capacity.…”

“…Their genetic correlation estimates were associated with large standard errors, however. More recently, Manafiazar et al (2016) obtained an estimate of 0.44 for the genetic correlation between angularity and lactation total DMI and a similar genetic correlation estimate between DMI and dairy strength (0.50) in Canadian Holstein cows using feed intake data recorded under experimental conditions.…”

“…Heritability estimates for DMI across lactation ranged from 0.21 to 0.40 in a recent study on the firstparity Holstein cows by Manzanilla-Pech et al (2014). Manafiazar et al (2016) obtained higher heritability estimate for lactation total DMI (0.27) in Canadian cows indicating that regulation of feed intake has a substantial genetic contribution and can be successfully altered through selection (Shonka et al 2015).…”

Analysis of pre-weaning feeding policies and other risk factors influencing growth rates in calves on 11 commercial dairy farms

“…Breed was, however, a significant factor in height increase from 1 to 63 days, which was greater for Holsteins than other breeds. Holsteins have been selected for stature, which has positive genetic correlations with milk yield and feed efficiency (Lin et al, 1987;Manafiazar et al, 2016).…”