NON-NUTRITIONAL COW-LEVEL AND AMBIENT TEMPERATURE RISK FACTORS FOR THE OCCURRENCE OF LEFT DISPLACED ABOMASUM IN HOLSTEIN COWS

Abstract

This retrospective cohort study (n= 13411 lactations) aimed to evaluate the association between temperature-humidity index at calving and cow-related variables with the occurrence of left displaced abomasum (LDA) in Holstein cows in a hot environment. Variables eligible for multiple logistic models were age at first calving, lactation number, temperature-humidity index at calving, metritis, lactation commenced following an abortion, dystocic parturition, premature calving, twin births, body weight at parturition, body condition score (BCS) at parturition, BCS change between calving and first artificial insemination (AI), and wither height at parturition. Significant risk factors for LDA were number of calvings [5.2% for primiparous vs. 8.3% for multiparous cows; odds ratio (OR)=1.3, P < 0.01], BCS at calving (6.6% for BCS ?3.5 and 8.4 for BCS <3.5; OR=0.75, P < 0.01), BCS change from calving to first AI (7.2% for <0.85 and 9.2 for ?0.85 units; OR=1.5, P < 0.01) and lactation initiated with abortion (1.6 for abortion and 10.2 for no abortion; OR=0.2, P < 0.01). Heat stress at calving was not associated with LDA. It was concluded that BCS <3.5 at calving and a greater BCS loss from calving to the first AI were associated with an increased risk of LDA. In contrast, initiation of lactation with abortion was related to a lower incidence of LDA.