The effect of dietary protein level on feed intake, digestibility and semen characteristics of Donggala Bulls

Abstract

This experiment examined the effect of dietary crude protein (CP) level on dry matter (DM) intake, digestibility and semen characteristics of Donggala bulls.  Four Donggala bull (weighing 440 ± 6.3 (SE), 36-40 months of age) were subjected to four dietary treatment containing different CP levels (11, 13, 15 and 17%) in 4x4 Latin square design.  The experimental animals were fed with corn stover and mixed concentrate of 25 and 75%, respectively, from the total diet which was allocated at 3.0 % BW/day. For all dietary treatment metabolizable energy (ME) was fixed at 11.50-11.55 MJ/kg dry matter (DM).  The experiment consisted of 4 runs, with one replicate (bull) per treatment level per run.  After each run, bulls were randomly allocated to a different level of CP. In each run, the bulls were fed their diet in individual pens over a 14 d preliminary and 7 d collection period.  Measurements of feed intake and  digestibility were done during 7 day each collection period.  Total DM intake was 2.81, 2.74, 2.75 and 2.78% BW/d, for Donggala bull given CP level of 11, 13, 15 and 17%, respectively.  Increasing CP intake resulted in significant increase (P<0.05) in dry matter digestibility (DMD), semen volume, spermatozoa concentration and motility of Donggala bulls.  However, increasing CP intake did not affect significantly (P>0.05) total DM intake, semen colour, consistency, pH, mass movement, sperm viability, mortality and abnormality.  It was concluded that increased dietary CP intake increased feed  digestibility and quality of semen and potentially to improve their reproductive performance of Donggala bulls.