Effects of limit‐feeding diets with different forage‐to‐concentrate ratios on nutrient intake,rumination, ruminal fermentation,digestibility, blood parameters and growth in Holstein heifers |
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| Authors: | Jun Zhang Haitao Shi Yajing Wang Shengli Li Hongtao Zhang Zhijun Cao Kailun Yang |
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| Institution: | 1. State Key Laboratory of Animal Nutrition, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing, China;2. Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, SK, Canada;3. Xinjiang Agricultural University, Urumqi, China |
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| Abstract: | The objective of this study was using a wide range of dietary concentrate levels to investigate the major effects of limit‐feeding on heifers. Twenty‐four Holstein heifers were blocked into six groups and fed with one of four diets containing different levels of concentrate (20%, 40%, 60% and 80% on a dry matter (DM) basis) but with same intakes of metabolizable energy for 28 days. Increasing levels of dietary concentrate caused decreased (P ≤ 0.02) intakes of dry matter (DMI) and neutral detergent fiber and total rumination time, but increased (P < 0.01) nonfiberous carbohydrates intake, ruminal concentrations of NH3‐N, propionate and butyrate, and digestibility of DM and crude protein. Dietary concentrate levels had no significant effect on most plasma concentrations and body measurements. The corrected average daily gain (CADG) and feed efficency (ADG/DMI, CFE) were linearly increased (P < 0.01) with increasing dietary concentrate levels when gut fill impact was removed. In conclusion, heifers limit‐fed high concentrate diets increased most ruminal fermentation parameters, CADG and CFE with similar body growth and blood metabolites as heifers fed low concentrate diets, and had the potential to be used as an effective feeding strategy in dairy heifers. |
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| Keywords: | Forage‐to‐concentrate ratio heifer high concentrate limit‐feeding rumen |
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