In nature, horses breed within a harem social unit that normally includes one mature breeding stallion and 5-10 mares with their immature offspring.
However, in human-controlled horse reproduction, decisions regarding the housing and management of stallions may contradict what nature intended, leading to undesirable behaviours, the occurrence of respiratory disease, and other health problems.
In this article, we examine the largely accepted trends of housing stallions, how they may impact on respiratory and reproductive health, and what improvements can be made.
Housing Stallions: Indoors & Isolated
In breeding facilities, the housing of stallions, which often involves isolation in an indoor stabled environment, is intended to prevent injuries and the spread of infections.
While these issues are worth avoiding, restricting stallions in their movement and interaction with other horses can lead to a myriad of health problems, affecting their respiratory health and semen quality, as well as impact on their welfare.
A 2019 study by Popescu et al investigated the welfare quality of breeding horses, including broodmares and stallions, under different housing conditions. They found the median welfare scores were markedly lower in stallions compared to broodmares.
The major factor attributed to these lower scores was the norm of keeping stallions in tie-stall housing, as opposed to broodmares that are typically kept in groups in free housing.
Dyspnea, which is difficult or laboured breathing, tendon and joint swelling, abnormal gait, and abnormal hoof horn quality were prevalent in more stallions than broodmares.
Respiratory Disease in Stallions
Studies indicate that stabled horses, including stallions, are at increased risk of respiratory disease, caused by viruses, bacteria, mould spores, dust, and other allergens.
Stable environments that have poor air and light quality are detrimental to stallion respiratory health. Restricting turnout time is also harmful to the respiratory system. Long periods spent in isolation can lead to unwanted behaviours and even lower libido.
In a 2021 study, Gehlen et al found “diseases of the respiratory, digestive, and musculoskeletal systems are more noticeable in individual husbandry, which can also be due to a higher stress load, poor stable climate, and lack of exercise”.
Semen Quality & Breeding Performance
Studies demonstrate that testosterone levels increase in stallions that live with mares and subsequently decrease in those that are housed with geldings and other stallions.
In nature, young stallions congregate in bachelor bands when they reach sexual maturity as opposed to harem stallions that have access to mares for breeding. In a domestic setting, most breeding stallions are housed near geldings and other stallions.
As a result, testicular size in stallions may decrease, ultimately lowering libido. Testicular size is a good indicator of a stallion’s sperm production capability. Stallions with smaller testicles will typically produce less sperm, which can affect their breeding performance.
A successful breeding program depends on the health and breeding performance of a stallion. Therefore, it’s imperative that improvements are made in the housing and management of stallions. We recommend:
- Preparing stallions for the energy demands of breeding season by ensuring they remain at a healthy body condition score of 5 or 6.
- Regular veterinary, dental, and hoof care is essential to the health and welfare of all stallions, as well as routine vaccination and de-worming.
- Maintain a clean and well-ventilated stable environment with ample sunlight. Minimise dust through regular cleaning and using a dust-free bedding.
- Provide stabled stallions with individual boxes that adjoin a turnout yard for daily exercise. If not possible, exercise stallions daily through in-hand walking.
- Gehlen, H., Krumbach, K., & Thöne-Reineke, C., (2021), ‘Keeping Stallions in Groups – Species-Appropriate or Relevant to Animal Welfare?’.
- Lane, T., (2014), ‘Housing of Horses’.
- McDonnell, S. & Murray, S., (1995), ‘Bachelor and Harem Stallion Behaviour and Endocrinology’.
- Popescu et al, (2019), ‘Welfare Quality of Breeding Horses Under Different Housing Conditions’.
Disclaimer: This article is not intended to replace professional veterinary advice. Always consult your veterinarian if your horse as any health-related issue or is exhibiting symptoms.