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Physically effective neutral detergent fiber content modulates chewing activity, rumen fermentation, plasma metabolites, and performance.

Y. Cao

Events

06-23-2020

Abstract:

169
Physically effective neutral detergent fiber content modulates chewing activity, rumen fermentation, plasma metabolites, and performance.
Y. Cao*1,2, X. Chen2, L. Wang1,2, J. Yao1. 1Northwest A&F University Yangling, Shaanxi, China, 2Harvard Medical School Boston, MA.

Subacute ruminal acidosis (SARA) continues to be a common and costly metabolic disorder in high-producing cows worldwide. To evaluate if increasing physically effective neutral detergent fiber (peNDF) in diet can prevent SARA in cows fed high concentrate diets. Thirty second-parity Holstein cows were randomly allocated to 3 treatment groups: H-peNDF8.0, M-peNDF8.0, and L-peNDF8.0, which were prepared by mixing the same total mixed ration for 10, 18, or 60 min, respectively. The peNDF8.0 intake was positively correlated with the peNDF8.0 contents in the diets. Total chewing and ruminating time was lower for the L-peNDF8.0 diet than for the H-peNDF8.0 and M-peNDF8.0 diets (P < 0.05). Rumen pH was higher in the H-peNDF8.0-fed cows than in the other 2 groups (P < 0.05). The H-peNDF8.0 and M-peNDF8.0 diets corresponded with higher acetate concentration, acetate:propionate ratio than the L-peNDF8.0 diet (P < 0.05), while H-peNDF8.0 and M-peNDF8.0 resulted in lower propionate and valerate concentrations than L-peNDF8.0 (P < 0.05). Lowering the peNDF8.0 content decreased the activities of ruminal carboxymethyl cellulase, avicelase, and β-glucanase (P < 0.05). H-peNDF8.0 resulted in lower total plasma antioxidant capacity, γ-glutamyl transpeptidase, albumin, and creatinine compared with M-peNDF8.0 and L-peNDF8.0 (P < 0.05). Somatic cell counts in milk were positively correlated with the dietary peNDF8.0 content. The feed and milk energy efficiencies were unaffected by the treatments. In conclusion, increasing the content of peNDF8.0 in diet could help alleviate SARA and improve animal health among early lactation cows fed a high concentrate diet by increasing peNDF8.0 intake, chewing activity, and rumen pH.

Keywords: physically effective NDF (peNDF), subacute ruminal acidosis (SARA), chewing activity.