Subclinical Ketosis: Reproductive Performance and Milk Yield in Dairy Cows Receiving Oral Glucogenic Precursors During Early Postpartum Period.

The objectives of the study were (1) to determine the effect of subclinical ketosis on milk yield on Days 7, 14 and 21 in cows that received oral glucogenic precursor in early postpartum period and (2) to compare the reproductive performance after a combination of automated estrus alerts and fixed-timed artificial insemination in subclinically ketotic and non-ketotic cows. Holstein Friesian cows (n = 464) received 500 mL of propylene glycol once daily for 10 days in milk. Overall, 122 cows (26.3%) tested positive for at least one SCK during the first 3 weeks, which left 342 cows (73.7%) with negative test results for SCK. The prevalence of SCK was higher (p < 0.01) on Day 7 (18.5%) than on Days 14 (7.7%) and 21 (8.4%) in cows. The high spontaneous recovery rate (74.4% in the first and 22.2% in the second measurements) was observed between Day 7 and Day 21. SCK prevalence was not influenced (p > 0.05) by milk production (high or low). Although no differences in milk yield were observed in the early postpartum period, cows diagnosed with subclinical ketosis showed a noticeable decline in milk production by Day 21. Moreover, SCK did not affect (p > 0.05) the percentage of estrus expression, the interval from calving to the first insemination and pregnancy rate. Semen type and parity were major factors for pregnancy rate (p < 0.05). In conclusion, subclinically ketotic status did not affect milk yield and reproductive performance in cows receiving oral propylene glycol during the early postpartum period. These findings suggest that the expected detrimental effects of SCK can be mitigated through early postpartum supplementation with glucogenic precursors and appropriate reproductive management.