Sunday, September 29, 2019

Compromised welfare in individually housed horses

ID 102693178 © Viacheslav Nemyrivskyi | Dreamstime.comHorses are commonly housed in individual boxes. While this may be convenient and prevent injuries from other horses, it may also be detrimental to the horse’s welfare, especially if access to pasture is limited.

A paper by Alice Ruet and colleagues investigated the effect of various management practices on the display of behavioural indicators of compromised welfare in housed horses.

The study involved 187 sport horses housed in individual boxes in four separate barns. They had no access to paddocks or pastures.

The study ran over a 9-month period. The research team recorded various management factors:

  •  Individual (age; gender);
  • Housing (window to outside; grill between boxes; bedding material);
  • Feeding (number of concentrate feeds a day);
  • Equitation (discipline; level of performance);
  • Quantity of ration; 
  • Activity (number of events during the study; hours ridden a week; hours lunged or on horse walker.)

They assessed the presence or absence of stereotypic or aggressive behaviour and whether the horse appeared alert or “withdrawn” (Neck horizontal at same level as back, fixed stare, ears and head static).

They found that horses that had a window opening toward the external environment for the total duration of the study and kept in straw bedding were less aggressive compared to horses that never had this factor and were kept on non-straw bedding.

They report: “Among the housing and management factors commonly observed in individual boxes, most of them did not significantly affect the welfare state of horses.”  

“Only three factors (straw bedding, a window opening toward the external environment, and reduced quantity of concentrated feed received daily) seem to be beneficial, but with limited effects.”

Horses that had a window opening toward the external environment for the total duration of the study and kept in straw bedding were less aggressive compared to horses that never had this factor and were kept on non-straw bedding. Horses kept on straw were more often recorded as showing “alertness” compared to those kept on non-straw bedding.

A grilled window on the wall between two boxes did not have a significant effect on the behavioural indicators.

Behaviour was not significantly affected by any of the factors relating to discipline, regularity of training, or level of performance.

The authors add: “Above all, the longer horses live in individual boxes, the more likely they are to express persistent unresponsiveness to the environment….The recurrent expression of this posture could reflect an internal state that is likely to be similar to depression in human beings.”

They conclude: “The main relevant result of this study remains that most of the tested factors had no influence on the expression of the behavioural indicators, in particular on unresponsiveness to the environment and stress-related behaviours. This implies that drastic changes in the living and management conditions should be required to improve the welfare state of animals.”

“To preserve the welfare of horses, it seems necessary to allow free exercise, interactions with conspecifics, and fibre consumption as often as possible, to ensure the satisfaction of the species’ behavioural and physiological needs.”

For more details, see:

Housing Horses in Individual Boxes Is a Challenge with Regard to Welfare
Alice Ruet, Julie Lemarchand, Céline Parias, Núria Mach, Marie-Pierre Moisan, Aline Foury, Christine Briant and Léa Lansade
Animals 2019, 9(9), 621;

Saturday, September 28, 2019

Keyhole vasectomy for standing horses

Male horses are usually castrated to moderate unwanted male behaviour and limit unintended reproduction.

Vasectomy, interrupting the vas deferens to prevent sperm being released, is an option to prevent breeding while still maintaining male behavioural characteristics. It is performed less frequently in horses than in other species.

However, a new technique has been described using laparoscopic (keyhole) surgery which could make it a more popular option. Previously, the operation required general anaesthetic and open surgery.

Surgeons at the University of Zaragoza have described a laparoscopic technique that can be performed in the sedated standing horse.  In a paper published in the Veterinary Record, they report that the method takes about 20 minutes to complete for each side.

The operation is carried out with the stallions sedated and restrained in stocks. Three portals (small incisions through which the instruments and viewing scope pass) are used, at sites in the paralumbar fossae – the depression between the spine, ribs and pelvis.

A laparoscopic vessel sealing device is used to cut and seal the vas deferens at two points.

In a small study of four stallions, the authors found no evidence of recanalization of the vas deferens, and no sperm in the ejaculate two months after the operation.

They suggest that laparoscopic vasectomy can be performed successfully in standing horses in a short time, and without altering horses behaviour. They advise that more cases are needed to properly assess the long-term outcome of the procedure.

For more details, see:

Application of a laparoscopic technique for vasectomy in standing horses
Vitoria, A., Romero, A., Fuente, S., Barrachina, L., Vazquez, FJ.
Veterinary Record (2019) 185, 345.

Friday, September 27, 2019

Exertional heat illness

ID 102693178 © Viacheslav Nemyrivskyi | Dreamstime.comHeat stress or exertional heat illness (EHI) in competing horses seems to have become more of a problem in recent years.

There are, however, few published studies into how common the problem is in racehorses and the factors that underlie it.

Typical signs include abnormal behaviour, such as head shaking, kicking out in a random fashion, pawing the ground, reluctance to move, and ataxia. Affected horses may take longer than normal to recover after exercise, with rapid breathing, prolonged increase in heart rate and excessive sweating. Severe cases may collapse.

Two studies from Japan have investigated the prevalence of EHI and risk factors for the condition in Thoroughbred horses racing on the flat.

In a paper published in the Journal of Equine Science, Nomura and colleagues (1) investigated the prevalence of post-race EHI and climate conditions at racecourses in Japan.

Overall, in races run under Japan Racing Association (JRA) between 1999 and 2018, they found an overall prevalence of 0.04% (387 cases out of 975,247 starters). 

There was a trend for more cases recently, with a prevalence of 0.07% in the last four years.

When climatic conditions at the three racecourses with the highest prevalence were evaluated, most of the races were found to have been held when wet bulb globe thermometer (WBGT) was between 28°C  and 33°C.

In the Equine Veterinary Journal a paper by Takahashi and Takahashi (2), reviewed records of horses diagnosed with EHI after flat races. Data from cases occurring between April and September over a 12-year period, were used for a case-control study. Each case was compared with three randomly-selected control cases to try to identify risk factors for EHI.

When the WBGT index was 28⁰C or higher, the risk of EHI was much higher than when it was 20 ⁰C  or lower. 

The risk of EHI was higher in July than August, although the temperature measured by WGBT actually reached higher levels in August. The authors suggest this indicated a lack of acclimatisation to the heat.

Other risk factors identified were:

  • Female horses or geldings were at greater risk for EHI than were uncastrated males.
  • Races longer than 1600m presented a greater risk.
  • Older horses (Age 4 years or more) were at greater risk than younger horses.

The researchers stress the importance of taking measures to cool racehorses immediately after races, especially when the WBGT index is ≥28°C.

For more details, see:

(1)    Prevalence of post-race exertional heat illness in Thoroughbred racehorses and climate conditions at racecourses in Japan.
Nomura M, Shiose T, Ishikawa Y, Mizobe F, Sakai S, Kusano K. 
J Equine Sci. (2019);30(2):17-23. 

(2)    Risk factors for exertional heat illness in Thoroughbred racehorses in flat races in Japan (2005-2016).
Takahashi Y, Takahashi T. 
Equine Vet J. (2019)