Thin and fat cows, and the nonlinear genetic relationship between body condition score and fertility

Abstract

Thin and fat cows are often credited for low fertility, but body condition score (BCS) has been traditionally treated as a linear trait when genetic correlations with reproductive performance have been estimated. The aims of this study were to assess genetic parameters for fertility, production, and body condition traits in the Brown Swiss population reared in the Alps (Bolzano-Bozen Province, Italy), and to investigate the possible nonlinearity among BCS and other traits by analyzing fat and thin cows. Records of BCS measured on a 5-point scale were preadjusted for year-season and days in milk at scoring, and were considered positive (1) for fat cows if they exceeded the value of 1 residual standard deviation or null (0) otherwise, whereas positive values for thin cows were imputed to records below -1 residual standard deviation. Fertility indicators measured on first- and second-parity cows were interval from parturition to first service, interval from first service to conception, interval from parturition to conception, number of inseminations to conception, conception at first service, and nonreturn rate at 56 d after first service. Production traits were peak milk yield, lactation milk yield, and lactation length. Data were from 1,413 herds and included 16,324 records of BCS, fertility, and production for first-parity, and 10,086 fertility records for second-parity cows. Animals calved from 2002 to 2007 and were progeny of 420 artificial insemination bulls. Genetic parameters for the aforementioned traits were obtained under univariate and bivariate threshold and censored linear sire models implemented in a Bayesian framework. Posterior means of heritabilities for BCS, fat cows, and thin cows were 0.141, 0.122, and 0.115, respectively. Genetic correlations of body condition traits with contemporary production were moderate to high and were between -0.556 and 0.623. Body condition score was moderately related to fertility in first (-0.280 to 0.497) and second (-0.392 to 0.248) lactation. The fat cow trait was scarcely related to fertility, particularly in first-parity cows (-0.203 to 0.281). Finally, the genetic relationships between thin cows and fertility were higher than those between BCS and fertility, both in first (-0.456 to 0.431) and second (-0.335 to 0.524) lactation. Body condition score can be considered a predictor of fertility, and it could be included in evaluation either as linear measure or as thin cow. In the second case, the genetic relationship with fertility was stronger, exacerbating the poorest body condition and considering the possible nonlinearity between fertility and energy reserves of the cow.

Body traits, carcass characteristics and price of cull cows as affected by farm type, breed, age and calving to culling interval

“…Concerning breed effects, the average BCS found in the present study was lower than that previously reported for the same breeds in large-scale observational studies in HF (Gallo et al, 1996), BS (Tiezzi et al, 2013), SI (Frigo et al, 2013) and RE cows (Gallo et al, 1998). The BCS found for HF in this study was comparable with that found in HF cull cows slaughtered without a previous finishing period (Vestergaard et al, 2007;Yan et al, 2009;Hazel et al, 2014).…”

Performance Profile of Dairy Animals Under Compromise with Dynamics in Body Condition Score. A Review

“…Early calving negatively affected milk yield and milk fat percentage in heifers, while showed higher protein percentage than those with late calving (Abeni et al, 2000). Correlations of body condition traits with milk production were moderate to high (-0.556 and 0.623) in Brown-Swiss (Tiezzi et al, 2013). Negative correlation of -0.316 (P<0.05) and -0.404 (P<0.01 exists between BCS and peak yield at 42 days and 56 days postpartum in crossbred cows, respectively (Singh, 2015).…”

“…BCS could be used as a potential indicator of fertility and functional traits (Tiezzi et al, 2013;Kadannideen and Wegmann, 2003). Negative energy balance inhibits LH pulse frequency and lowers level of blood glucose, insulin and insulin like growth factor, collectively limits the estrogen production by dominant follicles and resulting in extended period of post-partum anestrus and reduced fertility Pushpakumara et al, 2003;Butler, 2000).Holstein cows with BCS one point higher than average at 10 th week of lactation had 5.4 days shorter to first observed heat, calving interval 14.6 day shorter, days to first service 6.2 day shorter, a 9% better conception rate and 1.9 kg less daily milk than average (Pryce et al, 2001).…”

Fertility traits of purebred Holsteins and 2- and 3-breed crossbred heifers and cows obtained from Swedish Red, Montbéliarde, and Brown Swiss sires

“…To overcome this problem, many of the leading dairy countries have incorporated fertility traits into their national genetic evaluation systems (VanRaden et al, 2004;Miglior et al, 2005). Many studies have reported a negative correlation between milk production and fertility traits (Pryce et al, 2002(Pryce et al, , 2004, indicating that intensive selection of animals for milk production in the past decades may have affected fertility negatively, especially through worsening of body condition (Tiezzi et al, 2013). However, other factors may be associated with reduced fertility over time, including increasing herd size, greater use of confinement housing, labor shortages, and higher inbreeding coefficient (Lucy, 2001).…”