Peripartum responses of dairy cows to prepartal feeding level and dietary fatty acid source
2011
Hayirli, A. | Keisler, D.H. | Doepel, L.
This experiment was conducted to investigate the effect of feeding level and oilseed supplementation during the close-up dry period on energy balance (EB), hepatic lipidosis, metabolic status, and productivity in early lactation. Seventy-seven Holstein cows were blocked according to parity and expected calving date and then assigned randomly to 1 of 6 treatments in a 2 × 3 factorial allocation with 2 feeding levels: ad libitum (AL) or 30% feed restriction (FR), and 3 dietary fatty acid sources: canola seed, linola seed, or flaxseed at 8% of dietary dry matter (DM), to enrich the rations with oleic, linoleic, or linolenic acids, respectively during the last 4 wk of gestation. After parturition, all cows were fed a common lactation diet. Cows fed AL lost less body weight (−2.9 vs. −6.0%) and body condition score (+0.67 vs. −2.30%), and consequently were in more positive EB (+4.6 vs. −0.3 Mcal) during the prepartum period than cows subjected to FR. Postpartum, FR cows lost less body weight (−9.7 vs. −12.4%) and experienced less severe negative EB (−4.5 vs. −7.0 Mcal) than AL cows. Cows fed AL had higher plasma insulin (6.8 vs. 4.4 μIU/mL) and lower nonesterified fatty acid concentrations (436 vs. 570 mEq/mL) during the close-up period than cows subjected to FR. Cows fed AL tended to have lower liver glycogen content in early lactation than cows subjected to FR (4.4 vs. 2.9 μg/g of DM), but had similar triglyceride content (13.1±1.2 μg/g of DM). Fatty acid source did not influence response variables. In conclusion, eliminating intake depression by FR during the close-up period had positive carryover effects on EB and metabolic status during early lactation, but feeding linoleic and linolenic acids via unprotected oilseeds only had negligible effects on peripartum responses.
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