Iranian Journal of Veterinary Research
Volume:11 Issue: 3, Summer 2010

Fourteen primiparous Holstein cows (180.0 ±4.3 days in milk) with a mean (±SD) daily milk yield of 35.0 ± 1.3 kg and a body condition score of 3.2 ± 0.2 were allotted into two groups (n = 7), and were fed a ration consisting of (dry matter basis) 35% corn silage, 25% alfalfa hay and 40% concentrates. Salt was provided free choice. The experiment was performed during the period of heat stress, i.e., when the temperature-humidity index was greater than 72. One group was offered desalinated water containing 570 mg total dissolved solids (TDS) and another group was offered water containing 1400 mg TDS per L. Milk yield was measured weekly, and milk samples were taken on days 21 and 42 for determination of milk composition. Blood samples were taken on days 21 and 42 from the median caudal vein of the tail and the serum concentrations of Na+, K+, Ca2+, Mg2+, tri-iodothyronine (T3) and thyroxine (T4) were measured. Ruminal fluid was taken by rumenocentesis on day 42 for determination of volatile fatty acids (VFA) and pH. Milk yield, milk composition, serum concentrations of T3 and T4, Na+, Ca2+ and Mg2+, ruminal fluid VFA concentration and pH were not significantly affected by water TDS (P>0.05); however, cows receiving desalinated water produced 2 kg more milk per cow per day. Serum K+ concentration was significantly higher in cows consuming saline water (P<0.05). The present data indicated that water with a TDS of 1400 mg per L had no adverse effect on lactating cows; therefore, it is not necessary to desalinate water in the region under study. However, in light of the possible effects of saline water on thyroid hormones, further studies concerning the influence of saline water on the metabolism of high producing cows in hot climates are warranted.

The effect of subcutaneous injections of vitamin C on the seminal characteristics of Markhoz bucks (2–4-year-old) was studied. The bucks, trained to serve an artificial vagina, were randomly allotted into three equal groups (n = 4) and received daily either zero (1 mL normal saline; control group), or 20 (VitC20 group) or 40 (VitC40 group) mg per kg body weight vitamin C from July 06, 2006 to Oct. 06, 2006. Blood samples were taken from the jugular vein at monthly inter, als, and semen samples were collected at 15-day intervals. Testicular dimensions in the scrotum (circumference, width, and length) were also determined on the day before semen collection. The ejaculates were evaluated for volume, sperm concentration, pH, motility, and abnormal and live sperm. Testicular measurements were not affected by administration of vitamin C. The interaction between vitamin C and the sampling time was significant (P<0.05) for the concentration of vitamin C in the blood plasma and seminal fluid, sperm motility, sperm viability, sperm abnormality, and the number of live-normal sperm in the ejaculate. Vitamin C increased the levels of vitamin C in blood and seminal plasma. Both doses of vitamin C increased the percentage of progressively motile sperm showing forward motility. VitC40 injection for 90 days increased sperm motility and the effect was still evident up to 30 days after the cessation of injections. The percentage of live sperm and mass motility showed similar trends. Both doses were equally effective in decreasing the percentage of abnormal sperm. The total number of live and normal sperm in the ejaculate increased by vitamin C injections and the effect was still evident after the injections had been discontinued. The present data indicates the importance of vitamin C in the reproduction of male goats, as also shown for several mammalian species. They further show that under certain conditions, the in vivo synthesis of this vitamin in ruminants might not be sufficient for optimum reproduction.