THE PRODUCTIVE AND REPRODUCTIVE EFFICIENCY OF THE PREGNANT HEIFERS, MILKED AND SUCKLEDBALADI COWS UNDER DIFFERENT LEVELS OF NUTRITION

Twenty four pregnant Baladi heifers were used to investigate the effects of three varying feed recommendations during pregnancy and lactation periods on subsequent growth, production and reproduction performances. During pregnancy the heifers were randomly distributed among three experimental groups of eight animals each. Heifers were allotted to receive (G1), 100% of National Research Council (NRC), 100 % and 120% of Shehata allowances for G2 and G3, respectively. After parturition each group was divided into equal two sub-groups, milking and suckling, four cows for each sub-group. Animals were group-fed their respective diets in six adjacent separate open shaded yard and observed for reproduction behavior. The total DM intake by lactating Baladi cows followed the opposite trend as that DM intake by pregnant Baladi heifers. The higher of serum glucose was affected by dietary energy of pregnant heifers inG2 and G3 than this of G1 value. No significant differences were showed in serum glucose values between suckled and milked cows. The values of total serum protein, globulin and A/G ratio were not significantly different among groups. While, serum albumin affected by levels of TDN and DCP groups. Values of serum cholesterol of pregnant heifers fed low energy and protein (G1) significantly decreased compared with heifers fed high energy and protein (G2 and G3). However, cholesterol values of blood serum in lactating Baladi cows whose calves were reared artificially did not differ from cows suckling their own calf. T3 and T4 values of pregnant heifers are proportionally correlated with the levels of TDN and DCP. In addition, concentrations of T3 and T4 were not affected by milk removal systems. Prolactin concentration of lactating Baladi cows has a positive correlation with the dietary TDN and DCP and there was no significant difference between milked or suckled cows under the same level of nutrition. The average of body weight (ABW) of G3 through pregnancy period were significantly (P<0.05) higher than that of G1 and G2. The average body gain (ABG) and average daily gain (ADG) of cows in G2 and G3 were significantly (P<0.05) greater than those of G1. However, ABW of G3 through lactation period recorded the highest one followed by G1 then G2.ABW and ADG at the end of lactation period were not affected by milk removal system. Body weight, loss body weight after calving and calves weight of Baladi cows affected by the level of nutrition. Milk production and lactation period of Baladi cows in the 100% NRC group was highest, followed by cows in the 120% Shehata group, however cows in the 100% Shehata group was the lowest. The data showed that plan of nutrition or milk removal system did not affect milk fat, protein and lactose percentages. The mean of somatic cell count was significantly lower in the suckled cows especially in G2 than in milked cows under the same level of nutrition. Superiority of milked or suckled cows fed 100%Shehata allowances in the reproductive performance compared to other groups. From economical point of view use of G2 under the suckling system could be recommended to improve the productive and reproductive performance of lactating Baladi cows.