Effects of Different Proportions of Pennisetum Purpureum Silage and Natural Grass Hay on Feed Utilization, Milk Yield and Composition of Crossbred Dairy Cows Supplemented with Concentrate Diet

Abstract

Effects of different proportions of pennisetum purpureum silage and natural grass hay on feed intake, digestibility, milk yield and milk composition of crossbred dairy cows were assessed at Bako Agricultural Research Center by using ten crossbred cows of similar milk yield (6.2-8.5 kg/d), body weight (307.99±8.53), age of lactation (early lactation), but differ in parities arranged in switch over 5*5 double single Latin square design; being started at November /2013 and finished at March /2014. Experimental animals were fed adlibitum of natural grass hay and Pennisetum Purpureum silage at proportion of (T1) Natural grass hay ad libitum + Concentrate mix (0.5 kg/l of milk), (T2) 75% Natural grass hay + 25% Napier grass silage + Concentrate mix (0.5 kg/l of milk), (T3) Natural grass hay + 50% Napier grass silage + Concentrate mix (0.5 kg/l of milk), (T4) 25 % Natural grass hay + 75% Napier grass silage + Concentrate mix (0.5 kg/l of milk)  and (T5) Napier grass silage ad libitum + Concentrate mix (0.5 kg/l of milk), respectively. The concentrate mix is composed of 49.5% maize grain + 49.5% noug seed cake + 1% salt and supplemented with Concentrate mix at rate of  (0.5 kg/l of milk). Results of chemical analysis and digestability studies of experimental feeds indicated that Pennisetum Purpureum silage (CP=13.85%, ME=10.22 (MJKg^-1DM)) had better nutritive value than natural grass hay (CP=11.72% and ME=7.98 (MJKg^-1 DM)). The daily DM, CP, and ME intake were highly significant (P<0.001) among the treatments with the highest intake observed when cows were fed sole Pennisetum Purpureum silage (T5). Apparent DM digestibility of T5 (66.1) was higher (P<0.001) than T1 (63.4), T2 (63.6), T3 (64.1) and T4 (64.9%). Daily milk yield was higher (P<0.01) for T4 (6.60) and T5 (6.89) as compared to T1 (6.28 l/d). Composition of all milk constituents were not significantly (P>0.05) different among dietary treatments. Economic analysis indicates that use of Pennisetum Purpureum silage as basal diet results in a better economic gain than when natural grass hay is used. Therefore, the results demonstrated that Pennisetum Purpureum silage had better feeding value as compared to the natural grass hay for crossbred lactating dairy cows and can be conserved and used especially in the dry season when conventional roughages are in short supply and low in CP content.

Keywords:  Basal diet, Crossbred, Digestibility, Hay, Intake, and Napier grass silage.