Short communication: Supplementing with vitamin E may alter the fibrinolytic capacity of cattle

Vitamin E supplementation has been reported to decrease the incidence of cystic ovarian disease (COD) and retained placenta (RP) in cattle however the mechanism of action is not known. In humans, vitamin E supplementation twofold the daily requirements decreases plasma plasminogen activator inhibitor-1 (PAI-1) activity. As proteolysis may be involved in both COD and RP, vitamin E may be reducing these disorders in cattle through its effects on PAI-1. To evaluate the effects of vitamin E on plasma PAI-1 activity in cattle, six non-lactating beef cows (n = 3 per treatment) were injected with 0 (Control) or 2750 IU of vitamin E (Vitamin E) IM once every four days for 24 days (Day 0 = first day of treatment). Blood samples were collected every two days for 28 days starting on Day 0 and plasma PAI-1 and tissue-type plasminogen activator (tPA) concentrations and activities were determined. No differences (P > 0.05) were observed due to vitamin E supplementation in plasma PAI-1 and tPA concentrations and activities or concentrations and activities adjusted relative to the Day 0 value for each cow. Day of treatment was a significant effect in all tPA measurements. The ratio of adjusted PAI-1 to tPA concentrations did not differ (P > 0.05) due to vitamin E supplementation however the ratio of PAI-1 to tPA activity tended to be greater (P = 0.097) in Control compared to Vitamin E cows (1.0 ± 0.1 and 0.7 ± 0.1, respectively). These data suggest vitamin E supplementation may contribute to the reduced incidence of COD and RP in cattle by shifting the ratio of plasma PAI-1 to tPA activity to a state favoring proteolysis.

Effects of Feeding OmniGen-AF^®during Superovulation on <i>in Vitro</i>Development of Embryos Recovered from Donor Beef Cows

Embryo quality is crucial when selecting embryos for transfer. Variation in quality may be attributed to poor oocytes, semen, stress, inflammation, and potential immune system dysregulation. OmniGen-AF® (OG) feeding supports immune system function and animal health. Our laboratory recently reported lower percent degenerate embryos recovered and increased plasma progesterone in beef cattle donors fed OG during superovulation. In vitro development of embryos recovered from donor cows fed OG prior to collection is presented here. Embryos were recovered from 24 beef cows assigned to four treatment groups: 0 g OG/hd/d and 200 mg Folltropin®-V (FSH) (0/200);0 g OG/hd/d and 400 mg FSH (0/400), 56 g OG/hd/d, 200 mg FSH (56/200) and 56 g OG/hd/d and 400 mg FSH (56/400). Good to excellent quality early blastocysts were cultured for 8 d. and development through hatching, embryonic volume and plasminogen activator (PA) production were quantified. The complete protocol was repeated 90 - 120 d later as Replicate 2. Optimal development was observed by embryos recovered from 0/200 cows where percent blastocysts hatching was greater (P < 0.05) compared to 56/200 and 0/400 cows and embryonic volume was greatest (P < 0.05) in Replicate 1. However, percent blastocysts hatching from 0/200 cows was similar (P > 0.10) to 56/400 cows and embryos recovered from 56/400 cows in Replicate 1 produced more (P < 0.05) PA compared to all other groups. For cows superovulated with the standard 400-mg FSH dose, feeding OG supported in vitro embryo development similar to that observed for 0/200 cows.