Quality of chicken manure as cattle feed and its effect on composition of cow's milk and blood serum in a dry tropical pastoral system

Abstract

In order to evaluate the quality of chicken manure as animal feed and its effect on chemical and mineral composition of milk as well as on mineral composition of blood serum of dairy cows grazing in dry tropical conditions, 18 dairy cows of similar weight and number of births were studied. The cows were divided into two treatments: Tl = Only grazed and T2 = Grazed+supplemented ad libitum with chicken manure. Representative samples of chicken manure were analyzed for chemical and mineral content. In order to evaluate the effect of chicken manure on cattle when used as feed, milk and blood samples were taken every 15 days following a 30 days adaptation period. The milk's chemical composition was characterized using the following variables; urea, casein, fats, protein, lactose, total solids, non-fatty solids, cooling point, density and acidity, all of which were determined with the automated equipment Milko Scan ST-170. Mineral concentration of milk and blood serum was compared by examining values for Ca, Mg, Na, K, P, Cu, Fe and Zn with a Perkin-Elmer 2380 atomic absorption spectrophotometer using the Flame Emission method. In the case of Phosphorous (P), a colorimeter was used with the ammonium vanadate procedure. Results indicated the efficacy of chicken manure as a source of protein and minerals and statistical analysis revealed differences (p<0.05) in concentration of urea (3.4 vs. 4.6mg/100 mL), fats (3.47 vs. 2.24%), total solids (12.23 vs. 11.09%), K (1.53 vs. 2.24 g kg -1) and Zn (3.72 vs.5.22 ppm) in milk produced and in P (0.114 vs. 0.082%) in blood serum between Tl and T2, respectively. © Medwell Journals, 2012.