Effects of hay intake and feeding sequence on variables in faeces and faecal water (dry matter, pH value, organic acids, ammonia, buffering capacity) of horses.

This research demonstrates that both the quantity of hay consumed by a horse and the sequence in which the horse is fed can influence the microbial activity in its hindgut, which in turn can affect the acidity of the horse’s fecal matter. Specifically, feeding a horse at least 0.83 kg of hay per 100 kg of bodyweight each day, before feeding it oats, can help protect the hindgut from becoming overly acidic.

Research Objective and Methodology

• The purpose of this research was to study the effects of the quantity of hay ingested and the sequence of feeding on indicators of microbial activity within a horse’s hindgut.
• Six horses were fed varying amounts of oats and hay on a daily basis for 14 days. The ratio was 1.00 kg oats plus between 0.50 kg to 1.00 kg of hay per 100 kg of bodyweight.
• The oats were either fed 30 minutes prior to the hay or the sequence was reversed.

Findings

• Faecal dry matter, short-chain fatty acids (SCFA) and proportions of propionate and iso-butyrate were highest when oats were fed first.
• The buffering capacities, acetate proportions and a measure called the acetate-propionate quotient (A/P) were highest when hay was fed first.
• As the hay intake increased, there were rises in faecal pH, acetate proportions, A/P, and buffering capacities, but declines in dry matter, SCFA, and propionate proportions.
• The rise in A/P and buffering capacity induced by hay was much higher when hay was fed before oats.
• Levels of L-lactate and ammonia remained unaffected by the feeding sequence and hay intake.

Implications and Conclusions

• The research concludes that both hay intake and feeding sequence can influence the microbial activity within the horse’s hindgut, even when the concentrate level remains the same.
• It is suggested that in horse diets consisting of 1.00 kg oats per 100 kg bodyweight per day, amounts of at least 0.83 kg hay per 100 kg bodyweight per day should be offered first to protect the hindgut from acidification.
• With such a feeding sequence and hay quantity, behavioural abnormalities, not specified in this summary, were no longer observed.