Temporal folate status during lactation in mares and growth in foals.
OBJECTIVE
To identify changes in folate status of mares and foals during lactation and growth, respectively.


METHODS
20 Thoroughbred mares and foals.


METHODS
Pregnant mares, and following foaling the same mares with their foals, were maintained on mixed grass-legume pasture and fed either a traditional dietary supplement rich in sugar and starch (SS) or a dietary supplement high in fat and fiber (FF). Blood samples were collected monthly from mares and foals up to 6 months after foaling. Total folate concentration in feed and forage was determined. Analyses of plasma folate, RBC folate, plasma homocysteine (HCY), and milk folate concentrations were performed.


RESULTS
Mare plasma folate concentrations declined moderately during 6 months of lactation. Mare RBC folate concentrations initially increased after foaling up to 3 months but declined toward the end of the study. Plasma HCY concentration was higher for mares fed the SS supplement, compared with mares fed the FF supplement from foaling to 6 months of lactation. Milk folate concentrations decreased during the first 3 months and then increased. Foal plasma folate initially declined but then increased. Stable concentrations of RBC folate were observed in foals. Plasma HCY concentrations in foals were unaffected by growth during the last 5 months. References range values for plasma folate, RBC folate, milk folate, and plasma HCY concentrations in healthy lactational mares and young growing foals were determined.


CONCLUSIONS
Folate status was not impaired in lactating mares and growing foals under the conditions in our study. It appears that folate supplementation is not necessary.
Ordakowski-Burk
Amy L
AL
Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA.
Kronfeld
David S
DS
Williams
Carey A
CA
Gay
Louisa S
LS
Sklan
David J
DJ
D000821:Animal Feed / Q000032:analysis; D000818:Animals; D000833:Animals, Suckling / Q000254:growth & development*; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D005492:Folic Acid / Q000378:metabolism*; D006736:Horses / Q000254:growth & development* / Q000378:metabolism*; D007774:Lactation / Q000378:metabolism*; D008892:Milk / Q000378:metabolism*; D009752:Nutritional Status; D011247:Pregnancy; D013997:Time Factors
D005492:Folic Acid