The effect of straw particle size in high concentrate diets on chewing activity, sorting behavior and productive performance dairy cows

Articles in Press

Document Type : Research Paper

Authors

1 Department of Animal Science, College of Agriculture, Isfahan University of Technology, Iran.

2 Department of Animal Science, Isfahan University of Technology, Isfahan 84156-83111, Iran

Abstract

In this study, 12 dairy cows (milk =51±3kg/d) were used in a replicated 3x3 Latin square design with 3 experimental periods of 28 d (21 d for adaptation and 7 d for data collection) assigned to 3 experimental diets containing wheat straw as fine (Xgm=6.9mm, grounded by forage chopper), medium (Xgm=13.3mm, chopped by feed Mixer) and mixture (50:50) of medium (in TMR) and long (top dress) straw (Xgm=22.1mm; long). By increasing particle size of straw, sorting activity against long and in favor of fine were linearly increased. Cows fed fine straw consumed about 34% of their total diet within the first 4 hours after feeding, but cows fed medium or long straws consumed 40 and 41% of their diets, respectively. Total feed intake (24 h) was similar across the diets, but NDF intake was greater in cows fed fine straw than others. Eating time increased (from 338 to 368 min/d), but eating rate and rumination time (from 535 to 504 min/d) decreased with increasing particle size of straw. Nutrient digestibility was linearly decreased as a result of increasing particle size of straw. Milk production (47.2kg), FCM (41.2kg), milk fat (2.78%), protein (2.8%), feed efficiency (1.76) and rumen pH (6.3) did not differ across the diets. Overall, increasing particle size of straw increased initial feed consumption after delivery (within 4 hours), eating rate, sorting activity. Therefore, feeding fine straw (6.9 mm) in high concentrate diet resulted in more uniform consumption of particle and a better supply of forage fiber.

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Iranian Journal of animal Science

Articles in Press, Accepted Manuscript
Available Online from 03 February 2025

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History

  • Receive Date: 01 October 2024
  • Revise Date: 20 November 2024
  • Accept Date: 14 December 2024

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