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Welcome to 2019! 

January has already shown us what summer has to offer with very hot weather and more recently some welcome summer storms. We hope you have managed to catch some rain at your place.

We like to share what we are seeing in the field along with the usual reminders and tips about seasonally typical health topics. Recently a few of our vets have been called to see animals suffering from photosensitisation - a very painful and at times fatal affliction. 

Nickala explains in brief what photosensitisation is, how it is caused and what can be offered to animals in distress. 

Other articles for our first Large Animal newsletter for the year include weaner management and castration, health risks of confinement feeding, coughing horses and the impact of heat on ovine fertility. Read on. 

Contents of this newsletter

01  In the field..

02  Hay for Sale

03  Weaner management - manage the stress

04  Should you castrate at weaning?

05  Bovine respiratory disease in confinement feeding

06  Looking a horse in the mouth

07  How ewe can ride the summer heat wave

08  Why is my horse coughing?

01 In the field..
photosensitisation sheep

An affected animal showing classical signs of photosensitisation with skin around eyes badly 'burnt' and oh so painful. Thanks for the photo Andrew Denman.

Photosensitisation: much more serious than just sunburn.

Photosensitisation is where the skin becomes abnormally sensitive to sunlight.

Primary photosensitisation occurs due to animals consuming plants containing photosensitising substances such as Paterson’s curse, ragwort and heliotrope. Secondary photosensitisation occurs as a result of liver damage. Given the severe drought conditions and the influx of weeds, we have been seeing an increasing number of plant toxicities this season.

Symptoms include: redness, crusting and painful swelling of the skin. In sheep the face, ears and muzzle are usually the worst affected areas, however recently shorn animals can be affected anywhere on the body. In cattle, skin on the back, udder and areas of unpigmented skin are most affected.

Treatment commonly involves removing the animals from affected pasture, providing shade, anti-inflammatories and pain relief, antihistamines and in some cases antibiotics may be necessary. It is important to seek veterinary attention early, as death can ensue. The prognosis varies depending on the underlying cause and the severity of symptoms.

If you think your stock may be affected by photosensitization, please call us immediately - 63618388

02 Hay for Sale
Carol Wylie hay

Spot Ad

We have a client with oaten hay for sale if you are looking to source to feed stock or replenish depleted hay sheds. 

This is new season oaten hay cut and baled Christmas Eve. 4x4 bales, $90.

Contact OVH for further detail - 63618388.

03 Weaner management - manage the stress

Weaning is one of the most stressful events in the production cycle of beef cattle. When weaning is managed poorly the weaners lose weight and succumb to disease more frequently, which in turn increases the risk of them dying.

Conversely, however, when managed well, cattle continue to gain weight and the process increases the production system efficiency and maintains better cow condition.

The economics

+ Cows convert forage to milk at approximately 60% energetic efficiency (it takes ~5.5mj energy to produce a litre of milk, and milk is about 3mj/L)
+ Calves then convert 90% of the milk to lean tissue
+ This results in 54% (60% x 90%) energetic efficiency for the conversion of forage energy consumed by the cow into calf live weight gain.
+ As the calf gets older and the rumen starts to develop, this efficiency drops off substantially.

In summary, it is much more efficient to feed high-quality forage to a young calf, than it is to feed the cow to feed the calf.

When to do it

+ Weaning should routinely be done with calves down to 130kg, and under drought conditions down to 100kg.

Preparing for yard weaning

+ Managing numbers - batch wean if group sizes will be >100. 2.5m2 yard space is required per animal.
+ Vaccines (5 OR 7-in-1, BRD vaccines, Piliguard)
+ Drench – depending on worm egg count results which are reliable in grazing beef cattle from 4 months of age. Preferably use oral or injectable drench unless facilities are poor or fly/lice control is needed
+ High-quality pastures and nutrient dense feedstuffs
+ Fresh clean water – trough space 3cm/hd
+ Management of dust or mud in yards
+ Time for staff for daily handling during the weaning process
+ A set of scales to weight at the start and end of weaning

04 Should you castrate at weaning?

In the previous article, we discussed that weaning is one of the biggest stressors in the production cycle of a beef calf. Castration then may be a close second. To minimise the negative effects of castration, it should be done as early as possible and definitely prior to weaning. In extensive cattle country, the cost and logistics of mustering frequently make this impossible, however in the southern beef industry, this can be routinely achieved.

We have no preference for either castration by cutting or ring application however calves over 4 months of age present with a much higher complication rate from poor ring selection and/or application. 

Pain relief

The Australian animal welfare guidelines stipulate calves must be castrated or dehorned prior to 6 months of age unless pain relief is provided. Best practice is to perform castration and dehorning as young as possible and to consider pain relief regardless of age.

Pain relief options are:

Trisolfen

+ Trisolfen® is a local anaesthetic and antiseptic gel

Buccalgesic OTM

+ Buccalgesic OTM® is an oral form of meloxicam which is effective for both pain relief and reducing fever caused by infection. Buccalgesic OTM® has recently been approved for tail-docking and castration
+ Buccalgesic OTM® is only available through veterinary clinics

Meloxicam injection

+ Meloxicam is the active ingredient which is marketed by different companies in Australia.
+ A single dose via subcutaneous injection is effective for 3 days.

05 Bovine respiratory disease in confinement feeding

With most cattle throughout southern Australia being forced into confinement feeding, it is important to be on the lookout for bovine respiratory disease (BRD). This is a commonly occurring, multifactorial disease of intensification which can happen to all stock but is more frequent in weaners. The development of BRD is the combination of stress and infectious agents.

Stressors include: 

+ Transport
+ Lack of condition
+ Weather extremes
+ Co-mingling
+ Dehydration
+ Handling
+ Dust
+ Feed and water changes

Infectious agents include:

+ Viruses

- BHV-1 - Infectious bovine rhinotracheitis virus (IBR)
- BVDV (pestivirus)
- BRSV
- PI3 (influenza)

+ Bacteria

- Mannheimia haemolytica
- Pasturella multocida
- Histophilus somni
- Mycoplasma bovis

Of the above infectious agents, vaccines are available in Australia for BVDV, IBR and Mannheimia haemolytica.

Signs to look out for are:

+ Open mouth breathing
+ Nasal and oral discharge
+ Coughing
+ Drooping ears
+ Increased respiratory rate
+ Fever >39.3oC
Sudden drop in condition
+ Reduced appetite

Treatment

Treatment responses are good when the disease is detected early, and before severe damage has occurred to the lungs. A combination of antibiotics and anti-inflammatories are used along with isolation. Speak to us about this.

Impact on business

+ 70-90% of the cost of BRD is due to the reduction in weight gain.
+ There is a strong association between average daily gain and mortality rates due to disease
+ An increase in disease incidence and mortality rates will also reflect a decrease in average daily gains across the mob of cattle as there are animals among the group who are sub-clinically affected (not showing visible signs, but still sick).

06 Looking a horse in the mouth

All horses and ponies require dental attention at different stages through their life. With routine dental attention, you may avoid the need for extractions and invasive work later in life. 

A horse with poor dental health can lose weight and resent the bit. In addition, poor dental health increases the risk of colic as poorly chewed food can block the intestines. Young horses lose their baby teeth as their adult teeth erupt. Retained baby teeth, called caps, can trap food in the mouth causing painful gum disease and infections.

Over time chewing causes sharp points to develop on the cheek teeth which can cause painful ulcers on the gums, cheeks and tongue. Damaged teeth and gums can allow an infection to develop and spread to the root of the tooth, causing painful abscesses.

Signs of dental disease to look out for in your horse include: dropping feed, weight loss, foul breath and swelling of the face or lower jaw.

We are best able to perform a detailed dental examination and treatment safely and effectively using sedation, pain relief and X-rays if required. Call us for more info.

07 How ewe can ride the summer heat wave

It is understood that fertility is affected when sheep experience temperatures over 41 C for greater than 9 hours on the mating day or for 3 days after mating. This reduced fertility is due to early embryonic mortality. Given the extreme temperatures experienced in many regions in early January, many ewes are at risk of suffering embryo mortality.

Every ewe that slips one cycle because of heat stress needs another cycle to conceive. When heat waves occur during the mating period you should consider using a third or additional mating cycle as risk insurance. After an extended period of heat stress, producers should have their flocks pregnancy-scanned to identify non-pregnant and twin-bearing ewes, and plan re-joining the empty ewes in Autumn. Once producers have established which sheep have remained pregnant during this hot period, the producers should consider the effects of heat stress on the growth of the foetus.

If ewes are exposed to heat stress experimentally for the last 15 days of gestation, then the weight of the placenta and the foetus are reduced resulting in reduced rearing rates.

It appears that improving nutrition after heat stress is unlikely to improve the birth weights of growth-restricted lambs, although there will be improvements in lactation quality and in early post-natal growth. In the case of growth-restricted lambs, improved lactation is important for growth to weaning and subsequent weaner survival.

08 Why is my horse coughing?

During the drier months, we see an increase in the number of coughing horses. Regular or severe coughing, coughing during riding or over a long period of time suggests an underlying problem.

There are many causes of coughs in horses ranging from mild viral infections or allergies to severe bacterial pleuropneumonia. Coughing is often accompanied by a watery or yellow nasal discharge. An elevated temperature may be present and the horse may be inappetant and lethargic in more severe cases.

A veterinary examination is necessary to determine the severity of the underlying cause. Usually, mild viral infections will resolve without medical treatment. Allergies to environmental dust may require inhalant medications. Only coughs caused by bacterial infections will respond to antibiotic treatment.

Seek veterinary advice first if you have a coughing horse. Accurate diagnosis and treatment is most effective in avoiding using a merry-go-round of expensive and ineffective remedies.