Effect of Starch Source in Pelleted Concentrates on Fecal Bacteria in Prepartum and Postpartum Mares.
Authors: Pyles Morgan B, Fowler Ashley L, Bill Veronica T, Crum Andrea D, Hayes Susan H, Harlow Brittany E, Flythe Michael D, Lawrence Laurie M
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Starch Source and Fecal Bacteria in Periparturient Mares The type of cereal grain in a horse's diet typically influences hindgut bacterial populations, but grain processing methods such as pelleting may enhance starch digestion in the foregut, potentially negating these microbial effects. Researchers fed 18 Thoroughbred mares either oat-based or corn and wheat middlings-based pelleted concentrates from day 310 of gestation through 28 days postpartum, analysing faecal samples for Lactobacillus species, amylolytic bacteria, and cellulolytic bacteria populations at five timepoints across the periparturient period. Pelleting the concentrates appeared to eliminate the bacterial differences normally associated with starch source selection—neither pelleted formulation significantly altered the enumerated bacterial communities (P > 0.05). However, the transition around parturition did destabilise the hindgut microbiota: lactobacilli and cellulolytic bacteria populations dropped notably at day 1 postpartum (P < 0.05), whilst amylolytic bacteria remained stable throughout. These findings suggest that feed processing decisions may matter less for microbial management than previously thought, yet the periparturient period itself warrants attention from a nutritional standpoint, as the significant decline in beneficial bacterial populations may have implications for mare health, milk quality, and foal development during this critical phase.
Read the full abstract on PubMed
Practical Takeaways
- •Choice between oat-based and corn/wheat middlings pelleted concentrates appears equivalent in terms of hindgut bacterial effects in broodmares, simplifying feed selection decisions
- •Expect natural shifts in fecal bacterial populations around parturition regardless of concentrate type; this does not necessarily require dietary intervention
- •Pelleting may protect hindgut bacterial communities from starch source variation, making pelleted feeds a more stable option for sensitive mares if hindgut health is a concern
Key Findings
- •Starch source (oat-based vs corn and wheat middlings-based) in pelleted concentrates did not significantly affect fecal Lactobacillus spp., amylolytic bacteria, or cellulolytic bacteria populations (P > 0.05)
- •Pelleting of concentrates may reduce or eliminate effects of starch source on hindgut microbiota compared to minimally processed grains
- •Parturition caused significant decreases in lactobacilli and cellulolytic bacteria at 1 day postpartum (P < 0.05), while amylolytic bacteria remained unchanged across sampling dates
- •Fecal bacterial communities in mares were more influenced by reproductive status (periparturient period) than by dietary starch source