Wednesday, August 28, 2019

Study finds preference for steamed rather than soaked hay

Soaking or steaming hay are commonly used to reduce the respirable dust content of hay for horses. Soaking hay is also used to wash out some of the nutrients to help control weight and reduce the glycaemic response (the increase in blood glucose levels that occurs after feeding.)

In a study conducted at the University of Guelph, Ontario, Canada, Tiana Owens and her colleagues investigated the effect of soaking or steaming on first-cut timothy – alfalfa hay. They considered the effect on nutrient content of the hay, and on feed preference and glycaemic response in a group of Standardbred racehorses.

The research team offered each of thirteen horses a choice between two of these hays for 30 minutes. Blood samples were collected to monitor the glycaemic response. The trial was repeated until each horse had been presented with all possible combinations of hay.

The researchers found that horses consumed less soaked hay than dry or steamed hay (all on a dry matter basis). Horses also spent less time eating soaked hay than dry or steamed hay.

They report that soaked hay had lower concentrations of soluble protein, non-structural carbohydrates (NSC), and potassium compared with the same dry hay. Steamed hay did not differ significantly in nutrient content from dry hay.

In this study, soaking, or steaming, the hay did not have any detected effect on the glycaemic response.

For more details, see:

Nutrient content changes from steaming or soaking timothy-alfalfa hay: effects on feed preferences and acute glycemic response in Standardbred racehorses.
Owens T, Barnes M, Gargano V, Julien L, Mansilla WD, DeVries TJ, McBride B, Merkies K, Shoveller AK.
J Anim Sci. (2019) pii: skz252.

Maintaining hydration with rectal fluid

Administering water via the rectum can be a useful way of giving large volumes of fluid, a recent study suggests.

Common to the management of many disease conditions is the need to maintain fluid balance.

This may require large volumes of fluid to be administered over a short time. Intravenous administration introduces fluid directly to the circulation. Administration into the stomach via nasogastric tube is another option, but may not always be possible.

Another option, often not considered, is administering fluid into the rectum.

In a randomised controlled experimental trial, Adeel Khan and colleagues compared the effect of fluids administered rectally with fluids given by the nasogastric (NGT) and intravenous (iv) routes.

They gave six healthy horses each of three treatments (intravenous hartmann’s solution; polyionic solution through a nasogastric tube; and tap water per rectum.)

For the rectal administration, faeces were manually removed from rectum, and fluid introduced through a catheter tied to the tail. Horses tolerated the procedure well.

To assess the effect of the various routes of fluid administration, the researchers monitored changes in the blood. They found that the packed cell volume fell over time with all treatments, indicating the fluids had been absorbed. Total solids in the blood fell with intravenous and rectal fluid administration.

A report of the research, published in the Equine Veterinary journal concludes: “Rectal fluid administration requires clinical evaluation, but may offer an inexpensive, safe alternative or adjunct to i.v. fluid administration, particularly when administration via NGT is not possible or contraindicated.”

For more details, see:

Continuous fluid infusion per rectum compared with intravenous and nasogastric fluid administration in horses
A. Khan, G. D. Hallowell, C. Underwood, A. W. van Eps 
Equine Veterinary Journal (2019)

Monday, August 26, 2019

Can goldfish help keep horse’s water clean?

It may come as a surprise to see goldfish in a horse’s water trough. But in some places, it is a popular practice. Not only are the fish thought to slow the build up of algae, but it is claimed they also help control mosquitos by eating the larvae.

In fact, a recent survey of 672 owners or horse carers found that 44% had used fish to keep the water tanks clean at some time, and 18% currently used goldfish in their horses’ water.

Large water troughs / stock tanks tend to accumulate algae over time if not cleaned regularly. They can also become breeding ground for mosquitos.

But can goldfish really help maintain the quality of the water in horse water troughs? 

The survey formed part of a study by Devan N. Catalano and colleagues at the University of Minnesota.

Six adult horses were kept in a drylot which contained large (379L /100 US gallon) plastic and metal water tanks. Five fish were placed in one tank. After a month the tanks were cleaned, and the fish moved into the other tank. 

During the study, the research team monitored the water quality daily, recording total dissolved solids (TDS) and water turbidity (NTU). Once a week they measured the water chlorophyll-a content (the pigment responsible for the green colour of algae).

They found some differences in water quality between the two types of water tank. TDS was lower in the plastic tank, but the metal tank had lower turbidty and chlorophyll-a.

Tanks containing goldfish had lower total dissolved solids, but there was no other difference in water quality between tanks with or without fish.

Horses appeared to have no preference for either type of water container, or for the presence of absence of fish.

The researchers conclude that “goldfish do not improve water quality except for total dissolved solids.” They add: “frequent cleaning is important, especially in warm months and with plastic tanks.”

For more details, see:

The Effect of Goldfish (Carassius auratus) on Water Quality in Horse Stock Tanks.
Catalano DN, Heins BJ, Missaghi S, Hathaway MR, Martinson KL.
J Equine Vet Sci. (2019) 79:73-78.