Deep-stacked Broiler Litter as a Protein Supplement for Dairy Replacement Heifers

B. A. Hopkins and M. H. Poore

(Experiment in Progress)

Introduction

Broiler litter is a byproduct of the broiler industry that is causing concern due to environmental impact in areas of industry concentration. Deep-stacked broiler litter can be utilized as a feed for ruminant animals. Ruminants can utilize the nitrogen (primarily from uric acid), energy, and minerals in the broiler litter.

Objectives

This study is designed to evaluate the feeding value of deep-stacked broiler litter as a supplemental protein source compared to soybean meal for growing dairy heifers and to determine the effect of an additional source of rumen undegradable protein when heifers are fed broiler litter.

Materials and Methods

Fifty Holstein dairy heifers (approximately 500 pounds body weight) are being assigned to one of the following treatments with all rations formulated to contain 14% crude protein and 68% TDN on a dry matter basis:

1. 100% of supplementary crude protein from soybean meal.
2. 67% of supplementary crude protein from soybean meal and 33% of supplemental crude protein from deep-stacked broiler litter.
3. 33% of supplementary crude protein from soybean meal and 67% of supplemental crude protein from deep-stacked broiler litter.
4. 100% of supplementary crude protein from broiler litter.
5. 67% of supplementary crude protein from broiler litter and 33% of supplemental crude protein from a source of rumen undegradable protein.

Heifers receive their assigned diets for 112 days. Corn silage and cottonseed hulls are the forage and fiber sources.

Measurements and Analyses

Heifers are fed a total mixed ration once daily using Calan7 feeding stations with feed refusals recorded after each feeding. Daily dry matter and crude protein intakes will be calculated.

Ration and ingredient samples are obtained every 14 days throughout the trial and analyzed for nutrient analysis.

Body weights are taken before feeding on three consecutive days at the beginning and the end of the trial. Interim weights are taken every 28 days throughout the trial. Wither heights and body condition scores are determined at the beginning and end of the trial.

Blood samples are collected via jugular venipuncture at two hours post-feeding on day 56 of the trial and will be analyzed for plasma urea nitrogen and minerals.

Rumen fluid is also collected at this time using a stomach tube and analyzed for volatile fatty acids and rumen ammonia nitrogen.