A total of 18 Egyptian female buffalo heifers aging 7-11 months and having
197±12.0 kg LBW were divided randomly into three similar groups balanced for LBW
and age (6 animals in each). The main experimental basal diet was formulated from
concentrate feed mixture (CFM), berseem hay (BH) and rice straw (RS). Buffalo
heifers in the control group (G1) were fed CFM, BH and RS (control diet), while those
in the 1^s1 and 2^nd treated Group (G2 and G3) were fed the control diet supplemented
with 20 and 30 g yeast culture (YC) per head/day, respectively. Detection of oestrous
activity of heifers was performed at the 12th months of age using infertile buffalo bull.
The date of or. set of the 1⁵¹ oestrus was recorded for each heifer and considered as
indicator for achieving puberty age if concentration of progesterone was ~1 nglml in
blood plasma. Heifers reaching puberty (the 1⁵¹ oestrus) with LBW between 340->350
kg were naturally mating. Results revealed that heifers at puberty were insignificantly
heavier in G2 by about 6 kg and lighter in G3 by about 11 kg than those in the control
group (G1), being 339, 345 and 328 kg for G1, G2 and G3, respectively. At 1^s1 service,
heifers in G2 and G3 were insignificantly heavier by about 8 and 7 kg than in G1,
respectively (353.7, 361.5 and 360.2 kg, for G1, G2 and G3, respectively). At
conception, heifers in G2 and G3 were insignificantly heavier by about 4 and 8 kg than
those in G1, respectively (359.8, 363.5 and 371.3 kg, respectively). All heifers in G3
(100%) were conceived at 350-400 kg LBW and 84% of heifers in G2 and 67% in G1
were conceived at the same L8W category. Puberty age was insignificantly earlier by
about 31 days in G2 and significantly (P>0.05) earlier by about 75 days in G3 than in
G 1 (529.2, 498.5 and 454.7 days for G 1, G2 and G3, respectively). At 1 st service,
average age was insignificantly earlier by about 29 and 55 days in G2 and G3 than in
G1, respectively (549.0, 520.2 and 495.7 days for G1, G2 and G3, respectively).
Average age at conception was significantly (P>0.05) earlier by about 9.5% in G3 than
G1 and was insignificantly earlier by about 6.5% in G2 than in G1 (560.2, 523.7 and
506.8 days for G1, G2 and G3, respectively. On the basis of the foregoing results the present study indicated the beneficial
effects of yeast culture (Gustor nature) during pre-pubertal ages on reducing age of
buffalo heifers at puberty, 1^st service and conception in particular for diets
supplemented with 30 g/head/day.