Abstract

ABSTRACTThis study compared ad-libitum versus precision-fed diets with 2 forages and different levels of neutral detergent fibre (NDF) to evaluate rumen fermentation, diet digestibility, feed efficiency, and digesta passage rate. Eight Holstein heifers (18.4 ± 0.6 mo) fitted with rumen cannulas were used in a 2-factor, split-plot, Latin square design. The whole-plot factor was feeding system with ad-libitum or precision feeding and 4 heifers in each plot. The subplot included 2 factors: forage quality and NDF content. Diets were formulated to provide the same energy level (0.234 Mcal of ME intake/kg of empty body weight0.75 for precision-fed heifers and 110% of previous intake for ad-libitum-fed heifers. Forage quality and NDF level affected dry matter intake. Mean rumen pH was lower for ad-libitum than for precision-fed diets and volatile fatty acid concentrations were affected principally by forage quality. Ad-libitum diets showed faster rate of passage for solid feeds and fluids, increased rate of digestion, and shorter retention time in the rumen. In addition, both high NDF and low quality forage modified rumen passage rate and shortened retention time. Feed efficiency was improved in precision-fed heifers.

Highlights

  • Reducing costs associated with raising heifers is one of the important topics in present day dairy farming

  • Feed efficiency was greater for heifers that consumed low neutral detergent fibre (NDF) (LNDF) compared to high NDF (HNDF) (P ≤ 0.01)

  • In this study we showed that the reduction in DMI for precision feeding diets improved feed efficiency in comparison with adlibitum diets for dairy heifers

Read more

Summary

Introduction

Reducing costs associated with raising heifers is one of the important topics in present day dairy farming. Feed efficiency can be improved by reducing DMI and increasing nutrient density (Hoffman et al 2007; Zanton and Heinrichs 2009b). Reducing DMI in growing heifers increases nutrient efficiency due to improved nutrient digestion and a reduction in the metabolic expenses of nutrient absorption and oxidative metabolism for maintenance (Reynolds et al 1991), more energy is available to be used in growth (Moody et al 2007; Zanton and Heinrichs 2009b; Lascano and Heinrichs 2011). Precision-fed diets provide enough nutrients for adequate, economical growth without affecting future performance and milk production (Zanton and Heinrichs 2009b)

Objectives
Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call