Genetic Relationship of Body Energy and Blood Metabolites with Reproduction in Holstein Cows

Abstract

Body condition score (BCS), energy content (EC), cumulative effective energy balance (CEEB), and blood serum concentrations of glucose, β-hydroxybutyrate (BHBA), and nonesterified fatty acids (NEFA) were measured throughout first lactation in 497 Holstein cows raised on a large commercial farm in northern Greece. All these traits are considered to be indicators of a cow's energy balance. An additional measure of BCS, EC, and blood serum glucose, BHBA, and NEFA concentrations were taken approximately 2 mo (61 ± 23 d) before first calving. During first lactation, first service conception rate, conception rate in the first 305 d of lactation, interval from calving to conception, number of inseminations per conception, incidence of metritis, and incidence of reproductive problems of these cows were recorded; interval between first and second calving, and second lactation first service conception rate were also recorded. Random regression models were used to calculate weekly animal breeding values for first lactation BCS, EC, CEEB, glucose, BHBA, and NEFA. Single trait animal models were used to calculate breeding values for these traits measured on pregnant heifers before calving. Reproductive records were then regressed on animal breeding values for these energy balance-related traits to derive estimates of their genetic correlations. Several significant estimates were obtained. In general, traits that are known to be positively correlated with energy balance (BCS, EC, CEEB, and glucose) were found to have a favorable genetic relationship with reproduction, meaning that increased levels of the former will lead to an enhancement of the latter. On the other hand, traits known to be negatively correlated with energy balance (BHBA and NEFA) were found to have an unfavorable genetic association with reproductive traits. Body condition score, BHBA, and NEFA recorded early in lactation, and glucose concentrations measured in pregnant heifers had the highest genetic correlation with future reproductive performance. Results suggest that genetic selection for body energy and blood metabolites could facilitate the genetic improvement of fertility and overall reproductive efficiency of dairy cows.

Genetic association between body energy measured throughout lactation and fertility in dairy cattle

“…Genetic correlations were rather similar with all four traits (Figure 6), the highest estimates being with energy balance (20.64) and energy content (20.60) at the end of lactation. The latter is consistent with the range of weekly correlations (20.66 to 20.74) reported by Oikonomou et al (2008), despite their estimates being derived from a different methodology (genetic regression of DC on energy content) and pertaining to the first lactation cows. Genetic correlations between DC and BCS ranged from 20.30 to 20.53 in agreement with an average correlation of 20.46 reported by Veerkamp et al (2001) and an estimate of 20.30 between single-observation BCS and days open found in Dechow et al (2004).…”

“…Prolonged periods of negative energy balance have been associated with digestive and locomotive problems (Collard et al, 2000), metabolic disorders (Goff and Horst, 1997), udder-health issues (Banos et al, 2006) and reduced reproductive performance (Reist et al, 2003;Dechow et al, 2004;Oikonomou et al, 2008).…”

Energy balance of individual cows can be estimated in real-time on farm using frequent liveweight measures even in the absence of body condition score

“…In high-producing dairy cows, lengthy periods of excessive negative energy balance (EB) have been linked to problems such as reduced reproductive performance (Oikonomou et al, 2008;Cutullic et al, 2012), digestive and locomotive disorders (Collard et al, 2000), and metabolic diseases (Goff and Horst, 1997). Therefore, the ability to assess the EB for individual cows in real-time and on farm would be a highly desirable management tool, enabling the dairy farmer to rapidly detect excessive negative EB.…”

Significant differences in fertility between dairy cows selected for one QTL located on bovine chromosome 3 are not attributable to energy balance, although eating behaviour is affected

“…Cows in severe NEB had higher NEFA levels and a longer interval to first ovulation (Roche et al, 2000). Oikonomou et al (2008) reported a negative genetic correlation between NEFA or BHBA concentration and first-service conception rate. Moreover, a positive genetic correlation between body condition score and first-service conception rate has been reported (Veerkamp et al, 2001;Oikonomou et al, 2008).…”

“…Oikonomou et al (2008) reported a negative genetic correlation between NEFA or BHBA concentration and first-service conception rate. Moreover, a positive genetic correlation between body condition score and first-service conception rate has been reported (Veerkamp et al, 2001;Oikonomou et al, 2008). High-merit dairy cows had delayed first ovulation and commencement of normal luteal activity compared with lowmerit cows, in association with lower plasma glucose and insulin concentrations (Gutierrez et al, 2006).…”