Maternal Age, Parity and Nursing Status at Fertilization Affects Postpartum Lactation Up to Weaning in Horses.

The research investigated the effects of a horse’s age, the number of times it has given birth, and whether it was nursing when conception occurred, on the quality and quantity of lactation until weaning. The findings indicated that these factors significantly influence lactation and foal growth, which is useful information in managing broodmares.

Method

• The study involved a group of 43 Saddlebred mares and their foals that were reared together over a year.
• The mares were classified into different groups according to their age (young being 6-7 years old, old being 10-16 years old), the number of times they had given birth (primiparous meaning first-time mothers, and multiparous meaning they had given birth more than once), and whether they had been nursing a foal at the time of insemination.
• No young mares in the nursing stage or old mares that had given birth many times were available for the study.
• The researchers collected colostrum (the first milk produced after birth, rich in antibodies), monitored the milk production of the mares, and noted the foals’ weight at various intervals after birth (3, 30, 60, 90, and 180 days).
• The researchers also calculated the average daily weight-gain of the foals during each interval.
• The researchers analyzed the nutritional properties of the mares’ milk, including their fatty acid, sodium, potassium, protein, and lactose content.

Findings

• First-time mothers produced colostrum rich in immunoglobulin G (important for immune function) but had lower overall milk production and higher fat content in their milk.
• Foals of first-time mothers had a lower average daily weight gain in the first 30 days after birth compared to foals of mothers who had given birth more than once.
• Older mares produced colostrum with more saturated fatty acids (SFA), less polyunsaturated fatty acids (PUFA), and milk richer in proteins and sodium but poorer in short-chain-SFA.
• Mares who were nursing at the time of conception produced colostrum richer in monounsaturated fatty acids (MUFA) and PUFA, but their milk production in late lactation was reduced.

Conclusion

• The study concluded that a mare’s parity (number of foals she’s had), age, and whether she was nursing at conception significantly affect her colostrum and milk production, as well as the growth of her foal.
• These factors should be taken into account when managing broodmares.