WHERE YOU HANG YOUR HAY NET MAY AFFECT YOUR HORSE’S HEALTH
Italian researchers are investigating how eating from a hay net affects a horse’s posture and, potentially, his health over time.
Nets and bags that hold hay off the ground have been available for decades, but they have become increasingly common with the introduction of “slow feeder” styles that regulate how quickly a horse can eat. Concern that elevated feeders require horses to adopt unnatural postures led researchers at the University di Torino to design a study to quantify the effects of feeding hay from nets at various heights versus ground level.
For the study, six Warmbloods were filmed as they ate hay offered at three different levels: Placed loose on the stall floor, in a slowfeeder style mesh net hung to align with the horse’s cannon bones, and in the same net hung at the level of the horse’s elbows. Representative frames from each video of the horses eating were then analyzed and annotated to mark the relative position of various anatomical landmarks, including the angle the horse’s neck relative to the withers, the angle of the lower jaw relative to the underside of the neck and the overall topography of the back and neck.
The researchers found that feeding positions had a clear effect on each horse’s posture, but some parts of the body were more affected than others. When a horse ate from a lower hay net, for example, his back posture was similar to the one adopted when he was fed hay on the ground, but his neck shape was significantly altered.
“Therefore, feeding from a low hay-net position allowed a closer back posture to the natural ground position but that was not true for the neck posture,” explains Emanuela Valle, DVM, PhD, who worked with the PhD student Federica Raspa on the project. “For this reason, further studies are needed to investigate the horse’s neck postures in each feeding position.”
The changes noted in mandible angles were of particular concern to the researchers. “The smallest mandibular angle was found when horses were fed from the high hay net position,” says Valle. “We believe that this aspect is important to be considered from a welfare point of view, because reduced mandibular angle is caused by the hyperflexion of the neck, and it is well known that the hyperflexion of the neck inhibits air exchange and produces higher flow resistance. Moreover, the high hay net feeding position could be a risk factor for inflammatory processes affecting the temporomandibular joint over time.” All of this, she says, is also cause for further study.
Nonetheless, Valle does not recommend lowering hay nets because of the risk of entanglement. “We can’t suggest to the owner to hang the hay net at a low position, since this is a concern for the horse’s safety. We need to identify the right compromise between horse welfare, horse safety and management practices.”