The nutritional needs of mares and foals in the first six months following birth are becoming better understood following recent scientific and mathematical research in Portugal.

New curve graphs of mares’ milk generated from milking samples show the variations in levels of protein, fat, and lactose in the first 180 days of lactation. Total milk output per day is also represented. These graphs reveal that whereas lactose levels go up throughout the nursing period, fat and protein levels drop. All three components go through rapid changes in the first month and more gradual changes in the following months.

“According to our curves, protein and energy requirements of the lactating mare would be expected to be greater during the first and second months,” said study co-author Ana Sofia Santos, MSc, PhD candidate in equine nutrition, and researcher at the Center of Studies of Animal and Veterinary Sciences, University of Trás-os-Montes and Alto Douro. “This means that these are the critical points in the supplementation (of lactating mares) in order to limit their loss of body condition score.”

Total milk output reaches a peak of about 14 kg (31 lbs) at 31 days and then steadily drops down to nearly half that amount by the six month mark. By three months, the production is low enough to indicate starting nutritional supplements for the foals, Santos said. “That way we can limit the break on foal growth, and these foals will be better prepared for weaning, and they will eventually get through (weaning) better,” she said.

Equine Center

Lactation curves for milk output (kg) and milk components (g/k

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About The Author


Passionate about horses and science from the time she was riding her first Shetland Pony in Texas, Christa Lesté-Lasserre writes about scientific research that contributes to a better understanding of all equids. After undergrad studies in science, journalism, and literature, she received a master's degree in creative writing. Now based in France, she aims to present the most fascinating aspect of equine science: the story it creates. Follow Lesté-Lasserre on Twitter @christalestelas.

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