Relative increase in walking activity in lactating dairy cows submitted to timed artificial insemination: Risk...

The objectives of this study were: (i) to evaluate the associations between postpartum health disorders, relative increase in walking activity (RIWA) and expression of behavioral estrus intensity captured by pedometers; (ii) to assess associations between RIWA and pregnancy in cows submitted to timed artificial insemination (TAI). Lactating dairy cows (n = 881) were enrolled in the study. Cows were submitted to a 5d TAI protocol with insertion of a progesterone device. Pregnancy status was determined by ultrasonography on D30 after AI. During the postpartum period cows were categorized as healthy (n = 468), having a reproductive disorder (n = 185), metabolic disorder (n = 118), reproductive and metabolic disorders (n = 56), or clinical mastitis (n = 54). Healthy cows tended to have (P = 0.10) a greater RIWA and a lower proportion of healthy cows did not exhibit estrus (P = 0.03) compared with cows that had a postpartum health disorder. Similarly, ovarian status at TAI protocol commencement (P = 0.01), presence of twin pregnancy (P = 0.03), and season (P < 0.0001) were all associated with RIWA. Cows with a corpus luteum (CL) at TAI protocol commencement, carrying twins and those served during the cold season had an enhanced RIWA compared with those with no CL, carrying singletons and cows served during the hot season. In addition, healthy cows (P = 0.003) and cows showing estrus (P = 0.0002) had enhanced pregnancy per TAI compared with those with postpartum disorders, and those failing to exhibit estrus, respectively. Hence, cows that remained healthy during the postpartum had a greater RIWA, expression of behavioral estrus intensity and pregnancy to TAI compared with those that had a postpartum disorder.