Need to slow your fast-eater down?





Researchers at the Uni. of Minnesota have been looking at the effect hay net design has on intake rates & consumption times in adult horses.

Background

Equines have evolved as hindgut fermenters, physiologically designed to consume frequent, small forage-based meals that, in the natural setting, are spread over around 14 hours grazing each day. Modern management systems often severely restrict a horse’s opportunity to forage. Many performance horses are stalled, fed large amounts of concentrated grain meals, and have feedings limited to two or three times daily. This common management scenario can result in problematic health and behavioral issues, including development of ulcers, an increased risk of colic, and the development of stereotypic behavior including wood chewing, crib biting, and stallwalking. Access to long periods of foraging tends to decrease such health issues and some behavioral vices.

Furthermore, many horse farms tend to have high stocking rates and inadequate amounts of pasture further limiting foraging opportunities. Because of this, many horse owners and managers struggle to replicate the amount of time horses spend foraging in a natural setting. Although slow-feed hay nets are marketed as a way of replicating the natural foraging behavior of horses kept in modern horse management systems, consumption rates from such nets are unknown.

Method

This study measured the effect of hay net design on the rate of forage consumption in adult horses. Eight adult horses were fed in individual stalls for a total of two weeks each on the following regimes: a) fed hay loose from the stall floor, b) from a large haynet (15.2 cm holes), c) a medium haynet (4.4 cm holes), and d) a small haynet (3.2 cm holes). Horses had access to 2% of BWT hay per day regardless of feeding regime. Time to consumption and dry matter intake rates (DMIR) were calculated.

Findings

  • Average time to consumption was 1 and 3.4 hours for the floor and large-holed hay net, respectively, and 5.1 and 6.5 hours for the medium and small-holed hay nets, respectively.
  • Average DMIRs were 5, 1.3, 1.1, and 0.9 kg/hr for the floor, large, medium, and small-holed hay nets, respectively.
  • These results demonstrate that smaller sized hay net holes were effective at decreasing the rate of forage consumption and increased the time taken to consume the forage in adult horses.

Horses feeding from medium sized nets also took longer to consume their hay meal resulting in a reduced DMIR compared with horses feeding straight from the floor or large hay nets. Although the rate of hay consumption when feeding from a hay net had not been previously calculated, researchers have identified other physical barriers that can slow pasture and grain consumption. Using a grazing muzzle has been found to reduce pasture intake by between 30-80%. Similarly, using obstacles in a feed bucket has been found to increase time to feed consumption by 20–80%. Various methods are therefore available to slow consumption of hay, pasture, and grain when feeding adult horses.

This study observed that horses took 5.1 and 6.5 hours to consume their morning hay meal when fed from the medium and small hay nets, respectively. In comparison, horses fed from the floor consumed their hay meal in 3.1 hours. As previously stated, horses spend on average around 14 hours foraging each day, therefore if a horse is fed 2% BW each day split evenly between two meals and fed from the small hay net, foraging time would be approximately 13 hours daily, similar to that observed in a natural setting.

Recommendations

There are several potential benefits of lengthening forage consumption times (while simultaneously reducing forage intake rates) in horses. Increasing feeding frequency can lead to cycles of accelerated hindgut fermentation, largely due to the higher rate of feedstuff passing through the digestive tract. Increasing foraging time also increases digestibility of feedstuffs by decreasing the amount of feed introduced into the digestive tract at one time.

Extending foraging time has also been recommended as a strategy for reducing the incidence and severity of some stereotypic behaviors, including crib biting and wind sucking. Medium and small hay nets also provide a physical barrier preventing the horse from burying its muzzle into the hay. The presence of a physical barrier could be a potential benefit for horses diagnosed with respiratory diseases and decrease the likelihood of bolting large quantities of forage which may lead to choke.

Source:

Glunk, E.C., Hathaway, M.R., Weber, W.J., Sheaffer, C.C. and Martinson, K.L., 2014. The effect of hay net design on rate of forage consumption when feeding adult horses. Journal of Equine Veterinary Science, 34(8), pp.986-991.