Estrus traits derived from activity measurements are heritable and closely related to the time from calving to first insemination

Abstract

The aim of this study was to estimate genetic parameters for estrus-related traits that could improve selection for increased fertility due to improved ability of the cow to return to cycling and go into heat after calving. We compared the time from calving to first insemination (CFI) to 3 physical activity traits: the interval from calving to first high activity (CFHA), estrus duration (ED), and estrus strength (ES). We calculated CFI based on data from commercial Holstein herds that included the insemination dates for 11,363 cows. The CFHA, ED, and ES traits were derived from electronic activity tags for 3,533 Holstein cows. Estimates of heritability were 0.07 for CFI, 0.16 for CFHA, 0.02 for ED, and 0.05 for ES. We found a strong genetic correlation between CFI and CFHA (0.96). Genetic correlations between ED and CFI and CFHA were -0.37 and -0.68, respectively. Genetic correlations between ES and CFI and CFHA were -0.50 and -0.58, respectively. The heritability of CFHA and its strong genetic correlation with CFI suggest that including CFHA in the genetic evaluation of female cow fertility could improve the effectiveness of selection, because CFHA reflects the ability to return to cyclicity and go into heat after calving.

Symposium review: The choice and collection of new relevant phenotypes for fertility selection

“…Other activityderived traits described by Løvendahl and Chagunda (2009) were period of increased activity and strength of estrus, which exhibited low heritabilities of 0.02 to 0.08 and 0.04 to 0.08, respectively. Ismael et al (2015) noted strong genetic correlations for interval from calving to first high activity with the traditional ICF measure (0.96). As well, moderate correlations for estrous duration and estrous strength with ICF were estimated (−0.38 and −0.50, respectively;Ismael et al, 2015).…”

“…Ismael et al (2015) noted strong genetic correlations for interval from calving to first high activity with the traditional ICF measure (0.96). As well, moderate correlations for estrous duration and estrous strength with ICF were estimated (−0.38 and −0.50, respectively;Ismael et al, 2015).…”

Milk progesterone measures to improve genomic selection for fertility in dairy cows

“…In this thesis, the genetic correlation between C-LA and CI varied from 0.26 to 0.31. Ismael et al, (2015) also found a positive correlation between CFHA and CFS (0.96). This indicates that selection for a shorter interval from calving to resumption of ovarian activity would benefit overall fertility.…”

“…The low heritability of classical fertility traits makes selection for fertility less effective. Studies of physical activity derived traits e.g., the interval from calving to the first sign of high activity (CFHA) have reported higher heritability, ranging from 0.12 to 0.18 (Løvendahl and Chagunda, 2009;Ismael et al, 2015). Though CFHA has been suggested as a measure for resumption of ovarian activity, Ismael et al, (2016) showed that a drawback is that activity monitor derived fertility traits are seasonally sensitive.…”

“…However, there is a lot of competition with other fertility systems e.g., fertility systems based on heat detection and movement like physical activity monitors; these other systems are generally cheaper than the Herd Navigator. Furthermore, fertility traits based on physical activity monitors like interval from calving to first high activity have been shown to have substantial genetic variation, and have the potential to improve genetic selection for fertility (Løvendahl and Chagunda, 2009;Ismael et al, 2015). However, comparisons of pedometer measures with progesterone-determined estrus has shown that activity monitors cannot detect silent behavioral estrus (Løvendahl and Chagunda, 2016).…”