Dietary strategies to reduce the impact of high-concentrate diet on performance, ruminal fermentation and milk composition of dairy goats

• Published in: Journal of animal science 2018-12, Vol.96, p.474-474
• Main Authors: Lévesque, J, Dion, S, Brassard, M, Rico, D, Gervais, R, Chouinard, Y
• Format: Article
• Language: English
• Subjects: Acetic acid; Alpine environments; Caprinae; Diet; Dietary supplements; Fatty acids; Feeders; Feeding; Fermentation; Flax; Goats; High fat diet; Impact analysis; Lactation; Lipids; Mental depression; Milk; Palm; Palmitic acid; Propionic acid; Starch; Total mixed rations; Volatile fatty acids
• ISSN: 0021-8812; 1525-3163

This study investigated the use of dietary lipid supplements as a strategy to prevent or reduce the intensity of milk fat depression in goats fed high-concentrate diets. Thirty Alpine goats were housed in pens with Calan gate feeders at kidding, and received a total mixed ration with a forage-to-concentrate ratio (F:C) of 55:45 on a DM basis (27,4% of NDF and 17,9% of starch) during a pretrial period (23 ± 5 d). Data from the last 4 d of the pretrial period were used as covariates (d 0). Goats were blocked by milk fat concentration and randomly assigned to 1 of 3 diets containing a F:C ratio of 45:55 (25,3% of NDF and 19,4% of starch) for 41 d. Diets were: 1) Control (CTRL; no supplemental fat); 2) a high-palmitic acid diet (PALM; 16:0 at 1.9 % of DM; and 3) a high 18:3 n-3 diet (FLAX; 18:3 n-3 at 1.5% of DM). Data were collected on d 10, 20 and 41 and analyzed in a mixed model with repeated measures. In the CTRL group, feeding the high-concentrate diet reduced milk fat concentration from 4,34 to 3,53% (d 0 and 41, respectively; P< 0.01). PALM feeding increased fat yield on d 10 (12%) and 41 (21%) relative to CTRL and on d41 relative to FLAX (16%; all P< 0.05). No treatment effect was observed on ruminal pH (6,32; P >0.93) and individual volatile fatty acids (P>0,12). However, the concentration of ruminal propionate increased from 17.9 to 20.3%, while acetate and the acetate: propionate ratio decreased respectively from 68.1 to 62.0% and from 4.21 to 3.19 (P< 0.01) on d 41, relative to d 0. Feeding PALM can alleviate the reduction of milk fat synthesis in goats receiving high concentrate diets in early lactation.