YORDANKA ILIEVA1; VLADIMIR PLANSKI2; KALIN HRISTOV2; PENCHO PENCHEV1
1 Agricultural Institute – Shumen, 3 Simeon Veliki Blvd., BG-9700 Shumen, Bulgaria
2 University of Forestry, 10 Kliment Ohridsky Blvd., BG-1797 Sofia, Bulgaria
Ilieva Y., V. Planski, K. Hristov and P. Penchev, 2018. Comparative study on age of conception of buffalo heifers in different farming systems, Bulg. J. Agric. Sci., 24 (Suppl. 2): 52-56
With the aim to assess the effect of different farming systems on age of first conception, a comparative study was initiated on buffalo heifers from three farms for the period 2010-2015. All three farms (SIC, SIB and IMR) practice immediate separation of newborn from dam, 7-day colostrum and 3-month weaning period, live weight (LW) being monitored on Fm-3 only. Number of heifers assigned (n), farming system (FS), feeding in suckling period (SP) and use of natural-service bull (NS) were as follows: SIC – [n = 38, FS – free-stall plus pasture, SP – cow milk, NS – full time]; SIB – [n = 42, FS – tie-stall plus pasture, SP – buffalo milk, NS – by day]; IMR – [n = 69, FS – tie-stall plus yard, SP – milk replacer after first month, NS – by day, after heifers attain 380 kg LW]. The data were processed using the conventional statistical procedure. The results demonstrate the favourable effect of buffalo milk used in pre-weaning period, expressed in earlier age of conception in the heifers from SIB (729 days), as opposed to suckling cow milk on SIC – by 86 days (P < 0.05). Differences in farming system are implied by the considerably lower age of first conception established on SIB, in comparison to IMR (by 147 days, P < 0.001) where no pasture is used and breeding to bull is afforded after reaching a threshold live weight. The study found pronounced seasonality of reproduction, expressed in large percentage of heifers (75%) breeding in the period August-December. A tendency was also observed the heifers born in spring to conceive youngest.