Comparative study on feed intake and faecal output between Bos taurus and Bos indicus heifers

Abstract

Five Bos taurus and five Bos indicus heifers from 1,5 to2,0 years old weighing respectively 294,8 ± 6,74 kg and 221,20 ± i10,82 kg were fed “ad libitum” green Pennisetum purpureum grass and each received “per os” 8,0 g of Cr₂O₃ , administered individually in gelatine capsules. Grass ingestion was estimated through the differences between offered and rejected daily quantities. The faecal output was determined by the Cr₂O₃ recovery technique from faecal weighed samples; for that the equilibrium between ingestion and elimination of the indicator was previously determined: it was reached on the 4^th day both for taurine and zebuine animals. The taurine heifers ingested daily 24.984,44 ±  504,06 g of green grass, while the zebu ones ingested 13.428,89 + 691,31 g of the same per day, corresponding, respectively, to 4.894,02 ±_ 95,67 g and 2.466,51 ± 136,77 g of dry matter. On the other hand daily feacal output was 16.688,95 - 817,71 g for taurine and 6.491,59 ± 385,20 g for zebuine heifers, corresponding to 2.565,62 ± 76,88 g and 1.297,46 ± 58,58 g of dry matter, respectively. Expressing these results in percentages, it can be said that taurine heifers ingested 98% more grass and defecated 97% more than the zebuine, in terms of dry matter weight. Such conclusions open a large field of multi-disciplinary comparative investigations between Bos taurus and Bos indicus, envolving the territories of physiology, pathology, parasitology and epidemiology.