UBC Theses and Dissertations
Controlling energy intake in the prepartum period to improve transition cow health Vickers, Lori Ann
A common feeding practice during the dry period is to switch dairy cows to a low forage, energy dense diet 3 weeks prepartum, but this practice has been criticized as it may lead to the overconsumption of energy and increase the risk of metabolic disease postpartum. The aim of this trial was to compare the metabolic status of transition Holstein dairy cows fed a 77% forage diet (77F) (NEL = 1.46 Mcal/kg; NDF = 41%) versus those fed a 87% forage diet (87F) (NEL = 1.41 Mcal/kg; 48% NDF). Approximately 60 days before calving cows were dried off and fed the 87F diet. Three weeks before expected calving cows were randomly assigned to either remain on the 87F diet (n=42) or switched to the 77F diet (n=45). After calving, all cows were fed a common lactation diet (NEL=1.59 Mcal/kg). Dry matter intake (DMI) was measured daily from 2 weeks before to 2 weeks after calving. Blood was sampled twice-weekly prepartum and daily for 10 days postpartum. Subclinical ketosis (SCK) was diagnosed using a threshold of BHBA ≥ 1.0 mmol/L after calving. Metritis was determined by examining vaginal discharge. Cows on the 87F diet had lower DMI prepartum than those on the 77F diet (12.7 kg/d ± 0.3 vs. 15.4 ± 0.3, P <0.0001), but no difference was detected after calving (19.7 ± 5.5 kg/d; P=0.64). Although the calculated prepartum required energy intake was the same between treatments (15.3 ± 1.2; P=0.16), and both groups consumed in excess to these requirements, cows on the 77F diet consumed 5.1 Mcal/d more than those on the 87F diet. Postpartum BHBA levels were lower for cows fed the 87F diet prepartum (0.49 mmol/L ± 0.03 vs. 0.58 ± 0.03; P=0.003), and fewer animals on this diet were diagnosed with SCK (48.9% vs. 16.7%; P=0.001). We also noted a tendency for fewer cows to be diagnosed with metritis on the 87F diet (28.9% vs. 14.3%; P=0.1). There was no difference in daily milk production between treatments. These results indicate that feeding an 87F diet before calving can improve health in transition dairy cows.
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