Factors That Affect Energy Efficiency and Indirect Response of Selection for Efficiency on Related Traits

Manafiazar, Ghader; McFadden, T.B.; Goonewardene, L. A.; Okine, E. K.; Wang, Zhiquan

doi:10.5772/50776

Cited by 2 publications

(3 citation statements)

References 47 publications

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“…Our results suggested that LFCR was most likely influenced by production (LFCM) rather than by intake (LDMI), which is also supported by the results reported by Parke et al (1999) and Spurlock et al (2012). The above mentioned results indicated that phenotypically and genetically, LFCR would favour the animals with reduced BW to support her milk production, and selection for FCR would not necessarily improve feed efficiency and utilisation (Manafiazar et al, 2012). RFI, however, had strong (P < 0.05) positive genetic (0.51) and phenotypic (0.49) correlations with LDMI, which is supported by reports from other dairy researchers (Van Arendonk et al, 1991;Vallimont et al, 2011).…”

Section: Heritabilitiessupporting

confidence: 88%

“…In the present study, LFCM had a positive phenotypic correlation (0.17) with ABW. However, a wide range of genetic correlations (−0.42 to 0.48) between LFCM and BW were reported in the literature (Veerkamp and Emmans, 1995;Parke et al, 1999;Vallimont et al, 2010;Manafiazar et al, 2012). These results all together indicate that large cows may not necessarily produce more milk, and this conclusion is supported by VandeHaar (1998), whose results suggested an optimum point of relationship exists between milk production and BW.…”

Section: Heritabilitiesmentioning

confidence: 80%

“…The positive correlation between ABCS and LFCR in our study suggests that on average, losing BCS may be accompanied with an improvement (decrease) in LFCR. This improvement is supported in a review by Bewley and Schutz (2008) who summarised that losing one unit of BCS would increase milk production by around 2000 kg over a 305 days lactation period, and increase LGEE by 1.5 % (Manafiazar et al, 2012). However, improved LFCR could also be a drawback due to animal losing BCS to support milk production, possibly causing health and reproductive related issues in the animals (Vallimont et al, 2010;Spurlock et al, 2012).…”

Section: Heritabilitiesmentioning

confidence: 93%

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

Manafiazar

Goonewardene

Miglior

et al. 2016

Animal

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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.

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