Interaction between the sequence of feeding of hay and concentrate, and boiling of barley on feed intake, the activity of hydrolytic enzymes and fermentation in the hindgut of Arabian mares.

The research article examines the impact of the sequence of feeding of hay and concentrate and the hydrothermal treatment of barley on intake and hindgut fermentation in mares. The study utilizes six Arabian mares and changes both the order of feeding hay and concentrate, as well as the condition of the barley to study subsequent changes in digestive enzymes activities, intake, and fermentation.

Experiment Design

• The subjects of the study were 6 Arabian mares aged between 4 and 10 years with an average body weight of 410 ± 35 kg.
• The mares were offered a mixture of air-dried alfalfa and concentrate at a ratio of 70:30 as per the feed’s actual weight.
• The experiment was carried out in four successive periods of 14 days each. This period was divided into 8 days of adaptation and 6 days of sampling.
• Each meal session, the mares received their portion of concentrate either half an hour after (HC) or half an hour before (CH) they were fed alfalfa hay.
• The barley given was processed in two ways – it was either milled or boiled in water.
• For research purposes, rectal samples were taken directly from the rectum once per period.

Findings

• Mares subjected to the CH regime had a higher intake of dry matter compared to those under the HC regime.
• The CH regime resulted in a higher acetate to propionate ratio in rectal content than the HC regime.
• When fed under the CH regime, the mares had higher α-amylase (AA: EC 3.2.1.1) activity, an important enzyme in breaking down starches, compared to the HC regime.
• Mares that were fed boiled barley showed lower rectal concentrations of volatile fatty acids (VFA), specifically propionate, and a higher acetate:propionate ratio than mares fed milled barley.
• A higher microcrystalline cellulase (MCCase: EC 3.2.1.91) but a lower α-amylase activity was observed in mares fed with boiled barley compared to those fed with milled barley.
• Interactions were noted between the feeding sequence (FS) and type of barley (TB) on factors such as carboxymethyl cellulase (CMCase: EC 3.2.1.4), and the concentrations of the short-chain fatty acids propionate and valerate.

Conclusions

• The results indicate that feeding concentrate before hay and boiling barley can improve the hindgut environment in Arabian mares.
• The positive effects observed are mostly additive, meaning the benefits of each measure add to each other, and sometimes even synergistic, meaning they work together to create a greater effect.