The GREEN HORSE - sustainable horsekeeping

In the April/May 05 issue of The Green Horse you will find the following articles:

Talking Point and Information Exchange
A Question Of Water Quality by Karina Thullesen
Growing Equine Herbs - Dried Saltbush by Fiona Adams
Deeds, Steeds and Weeds- Ryegrass Incident High
Fire Prevention and Recovery
Weed Watch - Bridal Creeper by Nicola Field
Wild Horse Update
Preparing For The First Rains by Chris Ferreira and Tracey Bell

A Question Of Water Quality

by Karina Thullesen

When purchasing or establishing a horse property, the availability of a fresh water source for human and livestock consumption, is an important requirement. Quality of water can adversely affect the amount a horse will drink and ultimately its health, so it makes sense to check water sources and test regularly.


There are many factors that can affect water quality in rural and semirural areas of Australia. Some are natural occurrences in the water such as minerals or salts, others are caused by human activity, like farming or clearing of land, and others are of biological origin as a result of livestock urine and manure leaching into dams or other water sources.

Low Level Pollutants
Cloudy or discoloured water is an obvious water quality issue, although it is generally not a concern when used for watering horses or other livestock. Cloudy water can be caused by clay or organic matter but can be safely used in troughs, tanks, pasture or garden reticulation and washbays. One of the drawbacks to cloudy water is that small particles can sometimes cause blockages in reticulation and taps and, in the case of clay, may also cause some filtration problems in garden beds.

Iron can be another factor to consider, especially in bore water as it colours the water red and imparts a metallic taste, but poses no health risk for horses. It does leave brown stains when used for irrigation, which can be unsightly on stables, fences and buildings around the property. Iron can be removed from water by efficient aeration using a system of two tanks. Letting it sit in a tank for 24-48 hours is usually enough, adding Hydro lime or good quality builders lime at the rate of 25 grams per 1000L will speed settling. Once water is aerated and settled in the first tank, the cleared water can be transferred to the second tank ready for use, leaving the sludge to be flushed out of the first tank.
Some pollutants can be fairly safe at low levels but when in excess, they become a threat to the horse’s health either in the short or long term.

Contaminants
Odour in water can indicate some form of pollution or contamination, and should be checked - if the odour is similar to rotten eggs, (common in bores and dams) it is due to the presence of the gas hydrogen sulphide and is generally harmless. Most horses, once accustomed to the smell and taste, will readily drink this water. If concerned, you can filter the water with the use of activated carbon filters to remove taste and odours, or with an aeration system.

Although livestock can tolerate fairly high acidity levels in water, the corrosive effect can damage metal pipes and irrigation systems. Water, which is too acidic should be corrected as it can cause irreparable damage to the inner workings of pumps, tanks and valves used in troughs, bores and watering systems on properties. Acidic water can be stabilised by adding lime to raise the PH level.

A very visible and recurring water quality problem for horse owners is algae growth in water troughs, which can range from green to black and even a reddish brown slime covering the sides and floating on top of the water. In hot weather conditions, water troughs need to be monitored closely; if the trough is small and therefore needs refilling frequently, scrubbing and cleaning out the trough manually can become part of the routine of feeding and cleaning the horse’s yard. For larger troughs or tanks it can be very convenient to use a good quality stock tank cleaner. There are numerous brands available from stockfeed stores or a 100% natural product like Stocktankcleaner is easy to use. It breaks down organic matter and reduces excess nutrients, thus restoring and maintaining cleanliness and clarity in water troughs and tanks. (see www.enduranceriders.com).

There are also several additives which can help keep the water free of the slime including dolomite and copper sulphate, usually available at stockfeed or agricultural suppliers.

SALINITY
Salinity is one of the main water quality limitations in Australia. It can affect dams and bores as well as natural waterways such as rivers, creeks, lakes and soaks. The types of salts in water are mainly common salts (sodium chloride) calcium, magnesium bicarbonates, chlorides and sulphates - salinity is usually measured as the electrical conductivity of the water in millisemens per metre (mS/m). Horses are able to tolerate some levels of salt in their drinking water and will generally become accustomed to the taste, however the safe, upper limit of total salts is 6,500 mg/L.

Salinity of a water source may change over a number of years and can fluctuate within the seasons, with salt levels in dams, soaks or tanks increasing during summer with evaporation. Salinity in rivers and creeks reaches a maximum level immediately after the first rain of the wet season as salt left on the dry banks is flushed downstream, increasing salt levels - it then drops again with the increased flow of water. It is now widely accepted that increases in water salinity seen in many rural areas is usually due to over-clearing - because of this, water flowing from bushland areas is often fresher than nearby streams in cleared land. In the long term, this can be reversed by replanting vegetation on the affected land and establishing a healthy ecosystem. In the short term, water should be regularly tested, as high levels of salinity in the horse’s drinking water will affect their health and can ultimately cause brain damage or death.

Biological Pollution
Caused by fertiliser runoff, livestock urine and manure, or sewerage contamination, biological pollution introduces nutrients to the water, encouraging algae and bacterial growth, thus making the water unfit for horses. This can be prevented by fencing dams and streams or using vegetated buffer zones to control erosion in the catchment. Vegetation also filters out phosphorus-rich sediment and faeces, keeping the dams and waterways clean.

If there is any doubt about a water source used for watering livestock or humans, advice can be sought from the Environmental Health Officer of the local shire Council or the Health Department. Water may need to be sent to a laboratory and tested for bacteria content, chemicals or nitrates before it is deemed safe to use. Analyses for salt content and PH levels can be carried out by any district office of the Department of Agriculture.

Considering the many forms of pollutants which can affect water quality, property owners will need to follow sound management practices - including checking of water sources and testing - to ensure their horses’ good health.

Ryegrass Incidence High

The Department of Agriculture has advised WA livestock owners that meadow hay has the potential to cause annual ryegrass toxicity (ARGT) in livestock if it contains substantial quantities of ryegrass. The warning follows a number of recent horse fatalities linked to the consumption of toxic meadow hay.
Department principle veterinary toxicologist Jeremy Allen said although ARGT was most frequently seen in the wheatbelt, there have now been several cases along the coastal plain from Gingin to Busselton.

Dr Allen said ARGT was a serious and usually fatal disease of livestock caused by the consumption of annual ryegrass seed heads infected with a toxin-producing bacterium.
“Annual ryegrass forms the basis of much of the meadow hay that is grown and sold commercially for animal consumption,” Dr Allen said.
“Although ARGT occurs mainly in spring when stock are grazed on pasture with infected ryegrass seedheads, outbreaks can occur any time of the year from meadow hay containing the toxic seedheads.”
Dr Allen said signs of poisoning may include periods of weakness, loss of coordination, staggering, collapse, severe convulsions and eventual death. Occasionally animals may die before symptoms are noticed. The toxin is cumulative and signs do not appear until a near fatal dose is ingested. The time taken for clinical signs to appear depends on the amount of hay or pasture being consumed and the amount of toxin present in the seedheads.

The Department of Agriculture strongly recommends that all stock owners and feed store merchants ensure meadow hay containing annual ryegrass is tested for the presence of the bacterium that causes ARGT. The bacterium cannot be detected by simple visual inspection so the hay needs to be tested in a laboratory. Annual ryegrass and hay sampling and submission kits can be obtained from Department of Agriculture offices.

Dr Michael Proctor of Oakford Equine Hospital has diagnosed numerous horses with ARGT, at an increasing frequency over the past couple of years.
“I cannot stress enough to all horse owners the risk of feeding meadow hay that contains ryegrass infected with the toxin-producing bacterium,” Dr Proctor said. “The degree of suffering that is experienced by a horse with ARGT is extremely distressing to all people involved. I strongly urge all landholders, feed merchants and horse owners to act responsibly if we are going to continue to feed our horses meadow hay that contains rye grass.”

Landholders should also be aware that importation of infected meadow hay onto their own properties may lead to infection of their own pastures. Those who are unsure whether their existing annual ryegrass pastures may be infected should contact the Department of Agriculture for advice.

For further information and ryegrass/hay sampling and submission kits, contact your local Department of Agriculture office, the Department’s Animal Health Laboratories in South Perth on (08) 9368 3351 or the Small Landholder Information Service on (08) 9733 7777.