Aim of this study was to investigate the effect of flaxseed oil supplementation on the digestion, immunoglobulin concentration, some blood parameters, average daily gain, feed conversion and economic efficiency of suckling Friesian calves. A total of 28 newly born Friesian calves with weighing 31.42±1.9 kg were divided into two similar groups, 14 calves in each group. The first group (G1) was served as a control, while the second group (G2) was supplemented with 0.2 ml/kg LBW from flaxseed oil in suckling milk from birth up to weaning. Results showed that digestibility coefficients of DM, OM, CP, CF, EE and NFE and feeding values as TDN and DCP as well as feed intakes as TDN and DCP were higher (P<0.05) in G2 than in G1. Blood plasma immunoglobulins concentrations were higher (P<0.05) during different suckling intervalsin G2 than in G1. Red and white blood cells count, percentages of monocytes, neutrophils and package cell volume, and haemoglobin concentration increased (P<0.01) in G2 than in G1. Percentages of basophils, eosinophils and lymphocytes were not affected by supplementation. Concentration of total protein, albumin and globulin in plasma were increased (P<0.05-P<0.01), while, albumin to globulin ratio and concentration of total lipids, creatinine and urea-N concentrations decreased (P<0.01) in G2 than in G1. Plasma glucose concentrations and AST and ALT activities were nearly similar in both groups. Live body weight, average daily gain and feed conversion improved (P<0.001) in G2 than in G1. Economic efficiency was higher (P<0.05) in G2 than in G1. It could be concluded that flaxseed oil supplementation in milk of suckling Friesian calves (0.2 ml/kg LBW) during the suckling period improved growth performance and economic efficiencies as well as immune-response of Friesian calves without adversity effects on digestibility, haematological and biochemical parameters.

Genetic parameters for Friesian cows were estimated from 9155 lactation records for 3635 cows sired by 184 bulls. Multi-trait repeated animal models were employed using the REML procedure to estimate covariance components of total milk yield (TMY), service period (SP) and calving interval (CI). There is sufficient genetic variation (indicated by the coefficient of genetic variation) in total milk yield, service period and calving interval traits (15.6, 3.6 and 3.7%, respectively). Estimates of heritability for TMY, SP and CI traits were 0.170, 0.010 and 0.044, respectively. Permanent environmental variance ratios were 0.162, 0.017 and 0.048 for TMY, SP, and CI, respectively. Genetic correlations among SP and CI traits were high (0.998), however genetic correlations of reproductive with productive traits were unfavorable (0.512-0.661). The results indicated the possibility of continued selection for increased milk production which has deleterious effects on reproductive traits. The annual genetic changes were positive for TMY, SP, and CI (7.76 kg/yr, 0.076, and 0.24 d/yr, respectively). These positive trends indicate that there has been success in choosing better sires.The corresponding annual phenotypic changes for the same traits were positive (13.9 kg/yr, 0.029 and 0.82 d/yr, respectively). Positive annual genetic and phenotypic changes for SP and CI indicated that with improving milk yield the SP and CI will be increased. The financial situation of the farm is affected by the extension of the calving interval. The lower the calving interval, the more profitable the farm becomes, and prolonging this period for one day causes a financial loss for the farm.

Twenty lactating Friesian cows with average live body weight of 550 ±18 kg in their the 2 nd to 5 th parity were used to study the effect of replacing yellow corn grains (YCG) by discarded dates (DD) in concentrate feed mixture (CFM) at levels of 0, 33, 66, and 100% (w/w), on their productive and reproductive performance. Cows were assigned randomly to four similar groups (5 in each) according to milk yield, parity and live body weight (LBW). The levels of replacement of YCG by DD in CFM were0, 33, 66, and 100% (w/w) for G1 (control), G2, G3 and G4 as tested rations, respectively.Results showed that the contents of OM, CP and NFE were higher in YCGcompared to DD-ration, however the content of CF and ash showed an opposite trend. Cows in G3 (66% DD) recorded the highest (P<0.05) digestibility coefficients of all nutrients, nutritive values and the intake of DM, TDN and DCP, followed by G2 and G4, while G1 (control) almost had the lowest values. The pH value in rumen liquor markedly decreased after feeding and its values 3 h after feeding were lower (P<0.05) with the DD-rations than control. The highest TVFA's concentration in rumen liquor was recorded with in G3 after feeding, while the lowest concentration was found in G1 after feeding. Ammonia-nitrogen concentration in G3 was higher before and after feeding than the other treatments. Cows in G3 had the highest concentrations of total proteins, globulin and glucose and the lowest concentrations of albumin and total lipids in blood plasma. Yield as actual milk and 4% FCM were higher (P<0.05) for DDrations than those of control, being the highest in G3. Cows in G3 recorded the highest (P<0.05) percentages of fat, protein, and total solids in milk. Cows in G3 showed the best feed efficiency (DM, TDN and DCP: 4% FCM) compared with those fed the other rations (P<0.05). Average daily feed cost was higher (P<0.05)in G2 and G3 as compared to G1 and G4. While, cows in G3 showed the lowest feed cost/ kg 4% FCM and the best economic efficiency followed by G4 and G2, while G1 had the opposite trends. Cows in G3 had the best of most reproductive traits as first estrus, first service, service period, number of service /conception and conception rate. It could be concluded that partial replacement of yellow corn grains by discarded dates at the level of 66% as a source of energy in concentrate feed mixture improved the feed intake, digestibility, rumen fermentation activity, yield and composition of milk, economic feed efficiency as well as the post-partum reproductive traits in Friesian cows.

Aim of the present study was to evaluate the effect of replacing yellow corn with different levels of discarded dates in concentrate feed mixture on, feed intake, growth performance, feed conversion, carcass characteristics and economic feed efficiency of fattening Friesian calves. Twenty male Friesian calves (241.20±2.14 kg and 11 mo of age) were randomly assigned into four groups (five in each). Discarded dates (DD) was used in partial replacement of yellow corn grains (YCG) (w/w) in concentrate feed mixture at levels of 0% (G1), 33% (G2), 66% (G3) and 100% (G4), respectively. Results showed that DD contained higher CF, ash, lucien, isolucien, lysine, methionine, cysteine and histidine contents and lower OM, CP and NFE contents compared with YCG. All DD-diets slightly increased feed intake up to 66% DD. Final body weight, total and daily weight gain, and relative weight gain were higher (P<0.05) in G2 and G3 than in G4 and G1. Feed conversion improved (P<0.05) with increasing DD level up to 66% in G2 and G3. Average weights of pre-slaughtered animals, hot carcass, and boneless meat were higher (P<0.05), while weight and percentage of bone decreased (P<0.05) in G2 and G3 as compared to G1 and G4. The highest percentages of dressing and boneless meat was in G2, followed by G3, while G1 and G4 showed the lowest (P<0.05) percentages. Rib cut weight was higher in G3 and G2 than in G1 and G4. Percentage of lean, fat and bone was higher in G2, followed by G3, G4 and G1, respectively. Economic feed efficiency was higher for calves in G2, G3 and G4 by 19.44, 30.56 and 21.53% compared with those in G1 (control group), respectively. The current study concluded that dietary incorporation of discarded dates up to a level of 66% instead of yellow corn had impact on growth performance, carcass traits and economic feed efficiency of fattening calves. In addition, using discarded dates as by-products in ruminant diets could be useful in reducing the environmental pollution in Egypt.

The current work was done to study the impact of supplementation Spirulina platensis alage into the rations of growing Friesian calves on feed intake, rumen fermentation activity, digestibility, growth performance and economic efficiency. Eighteen Friesian calves aged 12 months with initial live body weight of 219.06 ± 5.35 kg were divided into three groups for 150 days feeding trial. Calves were individually fed a basal ration composed of 50% concentrate feed mixture (CFM) + 30% corn silage (CS) + 20% rice straw (RS) on dry matter basis without supplementation (control, R1) or with 1 g (R2) and 2 g (R3) dry Spirulina alage/ head/ day. Results showed that calves fed R3 recorded significantly (P<0.05) the highest nutrients digestibility and feeding values compared with R2 and the control one (R1). Intake of total dry matter (DM), digestible crude protein (DCP) and total digestible nutrients (TDN) were nearly similar for the different groups. The concentration TVFA's was significantly higher, while pH values and NH 3 -N concentration were significantly lower (P<0.05) in rumen liquor with the two Spirulina rations compared with the control one. Total protein concentration in plasma increased significantly (P<0.05) with Spirulina rations compared with the control one, while the rest of blood metabolities did not affected by the dietary treatments. Final live body weight, total and daily weight gain, as well as the improvement of daily gains were significantly higher (P<0.05) for the high level of dry Spirulina compared with the low level of dry Spirulina and also the control one. Feed conversion as DM, TDN and DCP required for producing one kg weight gain were lower significantly (P<0.05) for calves with Spirulina rations compared with those of control. Average feeding cost was nearly similar for the different groups. Whereas, feed cost per one kg live weight gain was significantly lower (P<0.05) for the two Spirulina rations than that of the control one. As well as, total revenue of body weight gain and net revenue as well as economic efficiency were significantly higher (P<0.05) for calves fed Spirulina rations than those of control ration.