Nutritional evaluation of nitrogen fertilizer of berseem 2- Berseem fed as silage to goats

Mhsen, M.K.¹; H.M.A. Gaafar²; G.S. El-Santiel¹, H.M. El-Gendy² and E.A. El-Beltagi³

1- Department of Animal Production, Faculty of Agriculture, Kafrelsheikh University, Egypt

2- Department of Animal Production, Faculty of Agriculture, Tanta University, Egypt

3- Animal Production Research Institute, Agriculture Research Center, Dokki, Egypt

Abstract

Male goats were used to determine the effect of nitrogen fertilizer rate on nutritive values of silages made from berseem of the 1^st and 2^nd cuts with sugar can bagasse (70:30 on DM basis). The contents of DM, OM, CF and NFE decreased, but CP, EE and ash contents of fresh berseem increased with increasing the rate of N fertilizer. The pH value decreased, however TVFA's and NH₃-N concentrations increased with increasing the rate of N fertilizer for both the 1^st and 2^nd cuts of berseem silages. The contents of DM, OM, CF and NFE decreased, but CP, EE and ash contents of silages increased with increasing the rate of N fertilizer. The digestibility coefficients of DM, OM, CP, EE and NFE and TDN and DCP values of berseem silages by goats increased significantly (P<0.05), but CF digestibility decreased significantly (P<0.05) with increasing the rate of N fertilizer. Average daily DM, TDN and DCP intake by goats increased significantly (P<0.05) with increasing the rate of N fertilizer. The pH value decreased significantly (P<0.05), however the concentrations of TVFA's and NH₃-N increased significantly (P<0.05) in rumen liquor with increasing the rate of N fertilizer. The nitrogen (N) intake, digested excretion in urine and retained by goats increased significantly (P<0.05) with increasing the rate of N fertilizer. While, N excretion in feces did not significantly affected by the rate of N fertilizer (P>0.05). The counts of red blood cells (RBC) and white blood cells (WBC) and hemoglobin concentration in blood of goats fed the different silages increased significantly (P<0.05) with increasing the rate of N fertilizer. The DM intake and nitrogen excretion in feces were higher, however, ruminal NH₃-N, nitrogen excretion in urine and red blood cells were lower when goats fed silages of the 2^nd cut compared with feeding 1^st cut silage.

Key words: feed intake, digestibility, nitrogen balance, rumen activity, blood hematology.

Introduction

In intensive grassland management systems, high nitrogen (N) application increases grass growth and as a consequence grass can be harvested, either by grazing or by cutting, in earlier stages of maturity (vegetative, pre- and early bloom) giving high nutritive values and maximum voluntary intake of grass (Minson 1990).

Making silage of surplus fodders during their abundant growth period will not only help overcome the irregular fodder supply pattern, one of the major culprits for lower ruminant productivity, but it well also enhance fodder yield of multicut fodder crops by increasing their number of cuts. Moisture content of leguminous fodder could be reduced either by field wilting or by the addition of some absorbent. But field wilting is not desirable due to higher labor costs. Dry roughages high in DM and low in nitrogen content could be added to improve the DM of berseem before ensilation (Fransen and Strubi 1998).

A chief part of berseem clover (Trifolium alexandrinum L.) is ensiled to preserve its quality and nutritional value. It is possible through moisture and temperature reduction of silage and the use of additive materials such as chemicals and plant materials to silage contents. Among the plant materials, it can be referred to milled grains such as maize, oat and barley, also grain stubble and beet molasses (Fairchild 1992, Kennedy and Mackie 1995). Successful silage crop production is based on a number of key factors that include species and variety selection, soil type, soil pH, fertilizer regime, pest control, optimal harvest date and storage losses (O’Donvan et al 2000; Ross et al 2004a&b, King 2007).

The quality of ensiled material depends on the composition and nutritional value of fodder, type of ensiled fodder, variety and operations of harvesting and silage preparation. Indices such as pH, lactic acid, ammonia, color, scent and taste of ensiled materials are used to determine the quality of silage (Edwards 1997).

The objective of this study was to investigate the effect of nitrogen fertilizer of berseem on silage quality and composition, feed intake, digestibility, rumen activity and blood hematology of goats.