Abstract
The present study investigated the effects of the supplemental dietary energy source on early lactating cows in a positive energy balance. Cows in the control group were fed a basal total mixed ration containing high-quality hay as forage, and the dietary concentrate to forage ratio was 45:65. The corn supplementation resulted in a significant decrease in the milk fat content (P P = 0.15), whereas the fat supplementation resulted in a decreasing trend of the milk protein and lactose content (P ≤ 0.1). Additionally, the corn supplementation significantly decreased the serum 5-hydroxytryptamine level (P < 0.05). The results support the proposal that the source of supplemental dietary energy has varying effects on feed intake, lactation performance, and the intermediate metabolism of early lactating cows in a positive energy balance. 5-Hydroxytryptamine secretion may be associated with the varying effects of the source of supplemental dietary energy.
Highlights
Research significance: Postpartum dairy cows have an increased lactation yield and dry matter intake (DMI), with a peak lactation yield of 50 - 70 days in milk (DIM) (Struken et al 2011) [1] and a peak DMI at 70 - 98 DIM [2] (Meng et al 2002)
The results support the proposal that the source of supplemental dietary energy has varying effects on feed intake, lactation performance, and the intermediate metabolism of early lactating cows in a positive energy balance. 5-Hydroxytryptamine secretion may be associated with the varying effects of the source of supplemental dietary energy
Corn supplementation reduced the milk fat content, while fat supplementation reduced the milk lactose content; both values were significantly different from the control values (P < 0.05)
Summary
Research significance: Postpartum dairy cows have an increased lactation yield and dry matter intake (DMI), with a peak lactation yield of 50 - 70 days in milk (DIM) (Struken et al 2011) [1] and a peak DMI at 70 - 98 DIM [2] (Meng et al 2002). The dietary energy level can be improved through fat or concentrate supplementation to alleviate the negative energy balance. Concentrate produces more propionate (a precursor for gluconeogenesis) during rumen fermentation Both glucose and the precursor for gluconeogenesis play roles in targeting the amino acids in the blood for metabolism in the breast and promoting milk protein synthesis [10] (Rulquin et al 2004). It has been shown that supplementation with rumen inert fat or the abomasal infusion of long-chain fatty acids reduces the blood glucose level [8] (Hammon et al 2008). Research gap: The effects of the supplemental dietary energy source on rumen fermentation in cows have been extensively studied, but the effects on post-ruminal metabolism have not been as extensively investigated. Research question: The aim of this study was to examine the effects of the supplemental dietary energy source on
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
