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Is Colic The Only Reason For Bacterial Changes In The Gut? Probably Not

It's long been known that the best way to prevent ulcers in horses is to make sure they have something to eat—preferably forage—nearly constantly. But what happens if feed and hay are withheld to not exacerbate a problem, like colic?

Drs. Jaclyn Willette, Dipti Pitta, Nagaraju Indugu, Bonnie Vecchiarelli, Meagan Hennessy, Tamara Dobbie and Louise Southwood found that the bacterial population of a horse's gut changes if he has been without food for at least 10 hours.

Chronic gastrointestinal disease leads to a decrease in variety of bacterial species in the gut of humans and cattle; the same is thought to be true for horses.

The bacteria in a colicking horse's gut is distinctly different from that in a healthy horse's gut. While this could be related to intestinal problems and inflammation that is leading to the colic epsiode, other factors could be at play, including withholding feed, which is an essential tool in managing a horse with colic.

The study team used eight mares for a crossover study that withheld nearly all feed for 24 hours and then allowed each horse free-choice timothy hay for 24 hours. The horses had access to water at all times.

The researchers found that bacteria richness and diversity were significantly lower 10 to 24 hours after the fast began. This limited bacterial population persisted for 2 to 12 hours after the horses were given access to hay. The horse's gut returned to normal 18 to 24 hours after the hay was reintroduced.

The team concluded that the effect of withholding feed should be considered when interpreting data on species and amount of gut bacteria in horses. Their findings may help locate markers that will lead to the development therapeutic interventions for horses that are colicking.

Read the study here.

‘Vacations’ Not Always Relaxing For Horses

Though vacations can be a good way to relieve stress and relax for humans, new research has found that the same can't be said for horses that experience time off from work. A study out of Spain shows that horses that are in work regularly become stressed when they're turned out for a lengthy break. However, after a few weeks, the horse's stress levels decrease, allowing them to get in some quality vacation time, reports The Horse.

Dr. Manel Lopez-Bejar, of the Universitat Autònoma de Barcelona, Bellaterra, noted that the downtime is difficult on horses as it changes almost everything about their environment, including feeding, management and work routines.

Lopez-Bejar and a study team tested eight Spanish stallions owned by the Municipal Police of Barcelona, Spain, for stress caused by an increase in leisure time. The horses were turned out in a pasture for three weeks and not worked. The researchers clipped hair from each horse's abdomen once a month from August through February to analyze the hair for the presence of long-term stress, denoted in the cortisol levels. Five police stallions were used as controls and had their hair samples taken from November to October.

The police horses went on vacation during the last 22 days in August. They were removed from the stalls where they are traditionally housed while working, loaded on a van for a 45-minute trip and turned out in fields. The horses had no set routines and were exposed to unknown caretakers and horses.

The researchers found a significant increase in cortisol in the hair samples during the rest period. Though the move itself didn't stress the horses, everything else that lasted throughout the period did. Lopez-Bejar noted that this doesn't indicate that a vacation is bad, but that the horse is responding physiologically to an environmental change. The cortisol response should return to normal once the horse adapts to his new environment.

It's important to ensure that the horses don't remain in a constant state of stress, however, as this could compromise his welfare. When giving horses time off, it's imperative to monitor him to be sure he's adapting to his new normal—no matter how long that will be.

Change In Diet From Grass To Hay Hard On Horse’s Hindgut

Horses that have abrupt changes to the grass and hay in their diets have changes in the microbial population of their feces. The change from hay to grass has a higher risk of causing problems in the equine gut than swapping from grass to hay. These changes may alter the gut microbiota, which may cause digestive or metabolic disturbance.

Drs. Anna Garber, Peter Hastie, David McGuinness, Pauline Malarange and Jo-Anne Murray created an experiment to test the microbiota of six Welsh ponies that were changed from pasture to hay and grass back to hay. For 30 days before the experiment began, the ponies were on pasture.

The study used two 14-day periods; in the first period, the ponies were taken off pasture and fed hay for 14 days. The ponies were then turned back out on pasture and given unlimited hay as well. Fecal samples were collected at the start of each phase and then on days 1, 2, 3, 7 and 14 after the changes to the diet were made. The samples were analyzed to determine how many microbiota were present as well as to characterize the microbiome.

The scientists found that the microbiota in the fecal samples were diverse, but that their abundance changed with abrupt dietary changes. Ponies fed the diet of restricted hay had microbiota similar to those ponies fed just grass, but they differed widely with regards to abundance.

They conclude that abrupt changes from hay to grass may pose a higher risk for hindgut pH to drop and cause gastric disturbances compared to the dietary change from grass to hay.

Read the full article here.