The percentage of concentrate intake, daily milk yield, serum IGF-1, and estrogen level of small holders dairy cows based on blood urea nitrogen and pregnancy status

Background: The small holders dairy farming is the largest fresh milk producer in Indonesia. Reproduction depends on dietary proteins, and raised blood or milk urea, increased dietary crude proteins, and increased dietary protein degradability. Aim: The aim of this study was to find out whether concentrate intake given to Friesian Holstein dairy cow in smallholder farms affects the levels of blood urea nitrogen (BUN), estrogen, and insulin-like growth factor (IGF-1). Methods: Gradually, the sample was chosen from among 100, 50, and 21 dairy cows using the equality of variables as the control variable. Blood samples were taken concurrently on the seventh day (D+7), D+22 (D+22), and artificial insemination (D0). Three months following insemination, the pregnancy examination was conducted using the rectal palpation technique. Results: The results showed that milk production and BUN levels increased (p<0.05) along with increasing concentrate intake to a certain limit. Pregnancy and BUN-based estrogen levels on D0 and D+7 did not differ substantially (P>0.05) across the groups. In contrast to the group of non-pregnant cows with low BUN, the estrogen concentrations in the pregnant cows with low BUN and the non-pregnant cows with high BUN were lower on D+22 (P<0.05). IGF-1 levels in pregnant cows were higher (p<0.05) on D0, D+7 and D+22 at unbalanced IGF-1 levels in cows with BUN ≥ 18 or <18 mg/dl. Conclusion: This research is an effort to increase milk production by increasing concentrate intake must pay attention BUN level which turns up level of IGF-1, S/C and CI.