The effect of different levels of sodium chloride (NaCl) on water and feed intakes, milk yield and its composition and some physiological responses in Friesian cows was examined in this study during the three months of summer season (June, July and August). A total of 25 cows averaging 482.4±20.5 kg LBW, ranging 41-76 months of age and 2-4 parities was used. All cows were at post-partum period after 25 days of calving. The cows were divided equally (five animals) into five groups according to their LBW, parity and its milk production. The 1 st group cows were fed a basal diet without any treatment, that were considered as a control group (G1), and the cows in the three groups (G2), (G3) and (G4) were received a daily drinking water containing NaCl as 2000, 5000 and 7000 mg/l, respectively, during the experimental period. While, the 5 th group cows (G5) were received drink water containing 2000, 5000 and 7000 mg/l NaCl during the first, the second and the third months of the experiment, respectively. Results showed that rectal temperature values (RT, o C) were significantly (P<0.05) lower in groups G3, G4 and G5 than in groups G1 and G2 in June, July and August, and the lowest value was in group G3 in June month. Values of white skin temperature (o C) and respiration rate were significantly lower in groups G3, G4 and G5 than in groups G1 and G2. And values of black skin temperature (o C) were significantly lower in groups G2, G3 and G5 than in groups G4 and G1. Water intake values of the treatment groups were significantly (P<0.01) higher than the control group as follows 12.3, 30.56, 54.49 and 18.6% in G2, G3, G4 and G5, respectively, where the highest value of the water intake was in group G4. Total dissolved solids (TDS) of SO4, CO3, Cl, Na and Ca were significantly (P<0.01) higher in treated groups than in the control group, TDS were increased with the increased amount of salt in the drinking water. Concentration of total protein, albumin and globulin in blood plasma were not significant. Glucose concentration was higher significantly (P<0.05) in G4 and G5 than the control group. The effect of NaCl treatment in drinking water on daily milk production as actual milk yield, fat corrected milk (FCM) as well as fat and protein yields in G3 and G4 tended to be significantly higher than the control and other treatment groups (G2 and G5). Milk composition was not affected by salt treatments. Cows in groups G3, G4 and G5 showed significantly (P<0.05) lower somatic cell counts (SCC) in milk yield as compared with G1 and G2 groups. Conclusively, the obtained results recommend common salt addition to the drinking water at 5g/L to improve the performance and production in Friesian lactating cows.

A total of 24 Friesian cows between the 1 st and 3 rd parity and average body weight (LBW) of 512.6 ±15.5 kg were divided into three similar groups (n=8 each) based on their BW, parity and milk production of the previous season. Cows of the 1 st group (G1) were fed concentrate feed mixture (CFM) (control group). Cows of the 2 nd group were received oral dose L-tyrosine 50 g/cow at 21 day (G2) while those of the 3 rd group (G3) were received the same dose of G2 but on day 40. Throughout the experimental period, cows were machine milked and daily milk yield was individually recorded for the 1 st four months. Milk composition and somatic cell count were determined. Estrus was detection and cows in heat were inseminated. Also, number and length of estrous cycles from calving up to conception were recorded. Postpartum 1 st ovulation (PPOI), 1 st estrus (PPEI) and 1 st service (PPSI) intervals, number of services per conception (NSC), days open (DO) and conception rate (CR%) were calculated. Pregnancy was diagnosed by rectal palpation on day 60 postinsemination. Results revealed that L-tyrosine treatment improved (P<0.05) daily milk production of G2 and G3 by 15.6 and 16.3% compared to G1. G3 had higher (P<0.05) percentages of fat, protein and lactose as compared to G1 (3.64, 3.07 and 4.16 vs. 3.54, 2.75 and 4.00%), respectively. G2 had higher (P<0.05) percentages of protein and lactose (2.98 and 4.28%, respectively) compared to G1, while fat percentage was similar to G1. Treated cows with L-tyrosine showed lower (P<0.05) somatic cell count in milk as compared to G1. Postpartum estrous interval was shorter (P<0.05), by 11.5 days in G2 than G1, While, those of G3 showed longer period (+ 8.13 day) than G1. Days open in G2 and G3 cows was shorter (P<0.05) by 21 or 13.2 day, respectively, than G1. Number of services per conception was less (P<0.05) in G2 (1,63) and G3 (2.0) than in G1 (2.6). Conception rate increased (P<0.05) in G2 and G3 compared with those of control (50 vs. 75 and 100%).

Data on the pre-weaning growth traits of 815 Egyptian native baladi calves borned from the period 1993 to 2014 were used to study the non-genetic, and genetic phenotypic factors of pre-weaning growth traits. The data were collected from Animal Production Research Station at El-Serw, Ministry of Agriculture. Covariance component for birth weight (W0), weaning weight (WW) and average daily gain from birth to weaning (ADG) were estimated by using least squares and maximum likelihood (LSMLMW) computer program of Harvey (1990). Model included sirs and dams within sires as random effects, year and season of birth, sex of calf and parity of cow as fixed effects. In addition, cow weight at calving and suckling days were used as covariate. The means and standard deviations of body weight at birth, weaning, and average daily gain were 23.47±4.29 kg, 80.59±6.36 kg and 0.477±0.06 g/d, respectively. Statistically season and year of calving and parity of cow did not showed significant effects, but sire and sex of calf had significant effects on studied traits. The values of heritability were 0.15, 0.33 and 0.38 for body weights at birth, weaning and average daily gain from birth to weaning, respectively. The results showed that most estimates of genetic and phenotypic correlations among body weights and daily gain traits were positive.

The objective of this study was to evaluate the effect of some factors on somatic cell count (SCC) in milk, milk yield (MY) and milk compassion, as well as he relationship between SCC, MY and milk quality of Friesian cows. A total of 1250 testday were studied for 145 dairy Friesian cows during the consecutive period from March 2009 to April 2010 were collected. All Friesian cows ranged between 400 and 600 kg live body weight, 3-13 years of age and 1-8 parities. Cows of the experimental period were fed concentrate feed mixture (CFM), berseem hay, rice straw and corn silage (summer ration) and CFM, fresh berseem and rice straw (winter ration). Throughout the experimental period, cows were machine milked and daily milk yield was individually recorded. Milk composition was determined. Milk samples for SCC determination were collected monthly of calving to the end of lactation. Results revealed that SCC significantly (P<0.05) decreased in second and third-parities and higher in four and fifth parities. Milk yield was significantly (P<0.05) higher in second parity, and decreased in other parities. The SCC was significantly higher in summer, moderate in spring and lower in winter and autumn seasons. Milk yield was significantly higher in winter, moderate in autumn and decreased in summer and spring seasons. Milk protein and lactose were significantly higher (P<0.01) in summer and lower in winter season. The SCC, milk protein and lactose increased in summer ration, but MY decreased significantly (P<0.05) in summer ration. Somatic cell count increased significantly (P<0.01) at first 30 days of lactation (469×10 3 /ml) (early lactation), highly significantly (P<0.001) in the end of lactation (597×10 3 /ml), and deceased after 90 and 180 days of lactation. Milk yield was significantly (P<0.05) decreased by increasing SCC. Protein content was significantly (P<0.05) larger in milk (2.42 to 2.81), when SCC increased (200×10 3)to 1000×10 3 cell/ml milk. An Increase in SCC during the late of lactation was accompanied with decrease in MY, fat, lactose percentages and milk quality.

The objective of this study was to evaluate the effect of adding zinc (Zn), copper (Cu) and selenium (Se) to the ration on ovarian activity and reproduction performance of Friesian cows. A total of 39 Friesian cows between the 1 st and 3 rd parity and average 532.7±23.5 kg LBW was divided into three similar groups (n=13 each). Multiparous cows (n=10 in each group) were divided according to their LBW, parity and milk production of the previous season, while primiparous cows (n=3 in each group) were allotted on their LBW. Cows of the 1 st group (G1) were fed concentrate feed mixture (CFM), rice straw and corn silage (control). Cows of the 2 nd group (G2) were received 60 mg Zn, 20 mg Cu and 0.3 mg Se /kg CFM on day 30 prepartum to calving, while those of the 3 rd group (G3) were received the same diet of (G2) from calving to 60 days postpartum. Throughout the experimental period, oestrus was detected and cows in heat were inseminated. Also, number and length of ovulatery cycles from calving up to conception were recorded. Post-partum 1 st estrus and 1 st service intervals, number of services per conception (NSC), days open (DO) and conception rate were assessed. Pregnancy was diagnosed by rectal palpation on day 60 post-insemination. Results revealed that Pre-and postpartum supplementation of Zn, Cu and Se (G2 and G3) increased (P<0.05) body weight gain and body condition score as compared to G1. Interval from calving to 1 st oestrus was significantly (P<0.01) shorter in G2 and G3 (23.5 and 27.45 days, respectively) than the G1 (39 days). Post-partum 1 st service interval was significantly (P<0.05) shorter in G2 and G3 (42.5 and 44.15 days) than that in G1 (59.1 days). Supplementation of Zn, Cu and Se in G2 and G3 significantly (P<0.05) reduced NS/C to 1.7 and 1.8 services and DO to 77.6 and 79.8 days as compared to 3.6 services and DO of 128.0 days in the control group, respectively. The Zn, Cu and Se treatment increased conception rate (CR), being significantly (P<0.05) the highest in G3 (84.15%), modest in G2 (76.92%) and the lowest in G1 (53.85%). Supplementation of Zn, Cu and Se in G2 and G3 significantly (P<0.05) decreased average number of total ovulations and ovulatory cycles per cow compared with the control group. Average P4 concentration during the ovulatory cycles and P4 level prior to estrus incidence were significantly (P<0.05) increased in G2 and G3 as compared to G1. Ovulatory cycle length and interval to P4 peak during the ovulatory cycles were not affected by dietary supplementation.