| dc.description.abstract | Quarter Horse mares (n=28, 465-612 kg BW, 6-19 yrs of age) were used to
investigate the effect of organic selenium (Se) supplementation (Selenosource, Diamond
V Mills, Inc. Cedar Rapids, IA (SeM)) and DE manipulation on plasma, muscle, and
colostrum Se concentrations, plasma glutathione peroxidase (Gsh-Px) activity, foaling
parameters, and physical characteristics in mares and their foals. Mares were arranged in
a 2x2 factorial with two levels of nutrition, pasture (100% NRC DE) or pasture plus
grain (120% NRC DE) (fed at 0.75% BW (0.63 ppm Se)) and two levels of Se
supplementation (0 or 0.3 mg/kg DM) equaling four treatment groups: pasture (P),
pasture grain (PG), pasture grain Se (PGS), or pasture Se (PS). Mares were blocked
by expected foaling date and randomly assigned to dietary treatment within block. Body
condition score (BCS), BW, and rump fat (RF) were observed every 14 d beginning at d
0. Mare and foal plasma and muscle sampling began on d 0 (birth in foals). Plasma
continued every 14 d and muscle every 28 d until parturition (d 56 in foals). Upon
parturition, foaling parameters consisting of times: water break to birth, birth to placenta expulsion, foal standing, and nursing were recorded. Colostrum quality was determined
via refractometer and colostrometer analysis, and placenta weight, foal birth weight,
whither and hip height and body length were recorded. Maternal SeM supplementation
influenced (P<0.05) mare and foal plasma, muscle and colostrum Se concentrations.
Increased maternal DE influenced (P<0.05) mare and foal plasma and foal muscle Se,
mare BW, BCS, and RF. However, mare muscle Se was unaffected (P>0.05) by DE.
Mare and foal plasma Gsh-Px, foal physical characteristics, and foaling parameters were
unaffected by treatment (P>0.05). Greater (P<0.02) colostrum refractometer values
(Brix%) for P, PS mares were noted and PGS, P mares had shorter gestational lengths
(nutrition x SeM interaction (P<0.05)). These data indicate that maternal DE
manipulation and SeM supplementation influences mare and foal Se status, mare BW
and colostrum quality (Brix%), but not plasma Gsh-Px activity. Additionally, nutrition
and SeM supplementation may affect gestational length. However, despite treatments
there was no difference in foaling parameters or foal physical characteristics. | en |
