Effect of body condition change and health status during early lactation on performance and survival of Holstein cows

Body condition score (BCS) and disease records are commonly available in dairy operations. However, the effect of BCS changes (Delta BCS) considering specific health profiles has not been investigated extensively. The objective of this study was to assess the effects of different levels of Delta BCS on fertility, milk yield, and survival of Holstein cows diagnosed with reproductive disorders (REP; dystocia, twins, retained fetal membranes, metritis, and clinical endometritis), other health disorders (OTH; subclinical ketosis, left displaced abomasum, lameness, clinical mastitis, and respiratory disease), or with no disease events (HLT) within 40 days in milk (DIM). Data included lactation information from 11,733 cows calving between November 2012 and October 2014 in 16 herds across 4 geographical regions in the United States (Northeast, Midwest, Southwest, Southeast). Cows were evaluated for BCS at 5 +/- 3 DIM (BCS5) and at 40 +/- 3 DIM (BCS40) and the difference between BCS40 and BCS5 was classified as excessive loss of BCS (EL; Delta BCS <=-0.75), moderate loss (ML; Delta BCS = -0.5 to -0.25), no change (NC; Delta BCS = 0), or gain of BCS (GN; Delta BCS >= 0.25). Multivariable logistic regression was used for assessing potential associations between the outcomes of interest and Delta BCS and health. The effect of the interaction term Delta BCS by health group was not statistically significant for any of the study outcomes. The odds of resumption of ovarian cyclicity (ROC), in GN, NC, and ML cows were 1.94 (95% CI: 1.57-2.40), 1.59 (1.28-1.97), and 1.27 (1.10-1.47) times greater than the odds of ROC in EL cows, respectively. The odds of pregnancy at 150 DIM (P150) in GN cows were 1.61 (1.20-2.17) times greater than the odds of P150 in EL cows. Cows with REP or OTH disorders had smaller odds of ROC compared with HLT cows [REP: OR = 0.65 (0.56-0.76) and OTH: OR = 0.79 (0.68-0.92)]. For pregnancy outcomes, REP cows had smaller odds of pregnancy at the first artificial insemination compared with HLT cows [0.70 (0.58-0.84)]. Similarly, REP cows had smaller odds of being diagnosed pregnant by 150 and 305 DIM compared with HLT cows [P150: 0.73 (0.59-0.87), P305: 0.58 (0.49-0.69)]. Overall, average daily milk within the first 90 DIM was greater in EL (39.5 +/- 1.13 kg/d) and ML (38.9 +/- 1.11 kg/d) cows than in NC (37.8 +/- 1.12 kg/d) and GN (36.2 +/- 1.12 kg/d) cows. On the other hand, average daily milk within the first 90 DIM was lower in REP (37.0 +/- 1.11 kg/d) cows compared with OTH (38.7 +/- 1.12 kg/d) and HLT cows (38.6 +/- 1.11 kg/d). The magnitude of Delta BCS and the health status of early lactation cows should be considered when assessing subsequent cow performance and survival.

Automated summary

This study investigated the effects of different levels of Delta BCS on fertility, milk yield, and survival of Holstein cows with specific health profiles. The results showed that Delta BCS had a significant impact on resumption of ovarian cyclicity and pregnancy outcomes, while cows with reproductive or other health disorders had differences in milk production and pregnancy success compared to healthy cows.