Browsing by Author "Kasimanickam, Vanmathy R."

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    Calm Temperament Improves Reproductive Performances of Beef Cows
    Whittier, William Dee; Kasimanickam, Ramanathan K.; Assay, M.; Schroeder, S.; Kasimanickam, Vanmathy R.; Gay, John M.; Hall, John B. (Virginia Tech. Powell River Project, 2015)
    Profitability of a beef operation is determined by breeding season pregnancy rates and proportion of cows attaining pregnancy early in the breeding season. Many factors including temperament contribute to these reproductive parameters. The objective of this study was to evaluate the effect of temperament on reproductive performances of beef cows. In experiment 1, Angus and Angus cross beef cows (n=1546) from 8 locations received body condition score (BCS; 1-emaciated; 9-obese) and chute-exit and gait score (1 = slow exit, walk; calm temperament; 2 = jump, trot or run; excitable temperament). Cows were grouped with bulls (1:25 to 1:30; with satisfactory breeding potential and free of venereal disease) during the entire 85 day breeding season. Pregnancy status and gestation length of cows was determined by per-rectal palpation at 35 days after the end of the breeding season. Controlling for BCS (P<0.01) and handling facility (P<0.0001) and handling facility by temperament score interaction (P<0.001) the breeding season pregnancy rate was different between excited and calm cows [88.6% (798/901) vs. 94.1% (607/645); P<0.001]. Cows with excitable temperament took 24 more days to become pregnant in the 85 day breeding season compared to calm cows (median days to pregnancy: 35 vs. 59 days; P<0.0001). In experiment 2, Angus and Angus cross beef cows (n=1407) from 8 locations received body condition score (BCS; 1-emaciated; 9-obese) and chute-exit and gait score (1 = slow exit, walk; calm temperament; 2 = jump, trot or run; excitable temperament). All cows were grouped with bulls (1:25 to 1:30; with satisfactory breeding potential and free of venereal disease) during the entire 85 day breeding season. Pregnancy status was determined by per-rectal palpation at 2 and 6 months from the beginning of the breeding season to determine the pregnancy loss. Controlling for BCS (P<0.05), the pregnancy loss was different between excited and calm cows, 5.5 (36/651) vs 3.2 (20/623), respectively (P<0.05) In conclusion, beef cows with excitable temperament had lower reproductive performance than calmer cows. The modified 2-point chute exit-gait scoring method is repeatable and can be used to identify cattle with excitable temperament.
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    Tocopherol induced angiogenesis in placental vascular network in late pregnant ewes
    Kasimanickam, Ramanathan K.; Kasimanickam, Vanmathy R.; Rodriguez, Jacobo S.; Pelzer, Kevin D.; Sponenberg, D. Phillip; Thatcher, Craig D. (2010-07-12)
    Background Tocopherols have biphasic, proangiogenic and antiangiogenic therapeutic effects. The objective of this clinical trial was to clarify tocopherol's placental angiogenic potential in late pregnant ewes following oral supplementation. Methods Eighteen pregnant ewes during late gestation were selected for this study. Ewes were given oral supplementation of 500 mg of alpha-tocopherol (aT; N = 6) or 1000 mg of gamma-tocopherol (gT; N = 7) or placebo (CON; N = 5) once daily from 107 to 137 days post breeding. Serum was obtained at weekly intervals and tissue samples were obtained at the end of supplementation to: 1) evaluate tocopherol concentrations in serum, uterus and placentome; 2) evaluate relative mRNA expressions of Vascular Endothelial Growth Factor (VEGF), Placental Growth Factor (PlGF), endothelial Nitric Oxide Synthase (eNOS) and Hypoxia Inducible Factors (HIF) in uterus, caruncle and cotyledon; 3) analyze the morphometry of the placental vascular network. Results Supplementation of aT or gT resulted in increased concentrations in serum, placentome and uterus compared to control (P < 0.05). In aT group, mRNA expressions of PlGF, eNOS and HIF-1α in cotyledon were greater than the CON group. In gT group, mRNA expressions of VEGF, eNOS, HIF-1 alpha and HIF-2 alpha in caruncle and uterus, and HIF-1α in cotyledon, were greater than the CON group. Morphometry analysis revealed increased angiogenesis in the supplemented groups. Conclusion Daily oral supplementation of aT or gT increased angiogenesis in the placental vascular network in pregnant ewes during late gestation. Increase in placental angiogenesis may provide nutrients required for the development and growth of fetus during late pregnancy.