Genetic Profile of Total Body Energy Content of Holstein Cows in the First Three Lactations

Abstract

Weekly total body energy content (TBEC) was calculated for 444 Holstein cows in their first 3 lactations. These calculations were based on body lipid and protein changes predicted from weekly changes in body condition score and live weight of each cow. In first lactation, cows lost TBEC during the initial 8 wk, regained it by wk 22, and continued to build up their reserves until wk 37. Cows started lactations 2 and 3 with considerable reserves from the dry period that they used during the first 13 wk of lactation. Variance components for TBEC were estimated using random regression analysis allowing for heterogeneous residual variance. The genetic variance increased within each lactation, suggesting that the genetic component becomes more important as lactation progresses. The genetic correlations between very early (wk 1 to 4) and later stages of first lactation were near zero but they increased considerably between later lactation stages. Genetic correlations between TBEC on wk 5 of first lactation and the remainder of this lactation ranged from 0.64 for the more distant weeks to 0.99 for the immediately subsequent weeks. Genetic correlations with TBEC in second lactation were moderately high (0.68 to 0.70) for the early weeks (1 to 8) and decreased gradually to 0.56 for weeks at the end of lactation. For third lactation, these estimates ranged from 0.53 to 0.63. Genetic correlation estimates of TBEC in wk 12 of first lactation with subsequent first-lactation weeks varied from 0.79 to 0.99, whereas they ranged from 0.65 to 0.77 and from 0.57 to 0.68 in second and third lactations, respectively. The genetic correlation between TBEC in later weeks of first lactation and the rest of productive life increased as first lactation progressed, but the improvement di- 2616TBEC were used to predict second-and third-lactation energy content. The accuracy of these predictions increased with progressing weeks in first lactation, but about three-fourths of the improvement occurred by wk 5. Our results suggest that TBEC calculated after a month from the first calving may give useful information about the future energy content of a cow. (Key words: total body energy content, genetic variation, lactation, dairy cattle) Abbreviation key: LWT = live weight, TBEC = total body energy content.

Review: Deciphering animal robustness. A synthesis to facilitate its use in livestock breeding and management

“…In dairy cattle, physiological adaptations to lipid metabolism, and associated changes in gene expression, have been shown to favour lipid accretion in gestation and mobilisation in early lactation (Blanc et al, 2006). Given this, it is not surprising that the temporal pattern of change in body reserves throughout the reproductive cycles can be modulated by genetic selection (Banos et al, 2005). These genetically driven changes in Figure 6 Example of individual animal trajectories before, during and after an environmental perturbation for (a) milk yield and (b) plasma glucose in 16 dairy goats.…”

“…The first derivative of such profiles can be used as a measure of rate of change in the trait. Such models, commonly termed test-day models, have been fitted to longitudinal data for many performance traits including milk production, body condition score and growth rate (Berry et al, 2003;Banos et al, 2005). They offer a means to concisely describe key elements of robustness.…”

Short communication: Estimates of genetic parameters of body condition score in the first 3 lactations using a random regression animal model

“…In early lactation, increase in feed intake is not sufficient to meet energy requirements of milk production in dairy cattle (Block et al, 2001;Banos et al, 2005;Chebel et al, 2008). Cows therefore enter a negative energy state (Block et al, 2001) in which they mobilize tissue reserves to meet increased energy requirements (Friggens et al, 2004).…”

Heritabilities and Genetic Correlations of Body Condition Score and Muscularity with Productive Traits and their Trend Functions in Italian Simmental Cattle

“…Body condition score (BCS) assesses the energy reserves of dairy cows and is therefore commonly used as an indicator of the extent and the duration of the negative energy balance (Roche et al, 2009) in early lactation, period in which the feed intake is not sufficient to meet energy requirements of milk production (Banos et al, 2005;Chebel et al, 2008). Many studies reported a moderate heritability of BCS (from 0.25 to 0.35) in dairy breeds (Berry et al, 2002;Pryce and Harris, 2006;Dal Zotto et al, 2007).…”