Uralla Veterinary Clinic

116 Bridge Street, Uralla


Uralla Veterinary Tales August 2020

Uralla Veterinary Tales

 

What a year 2020 has been so far! It has been wonderful to hear about all the rain falling in our area in recent weeks and months and to see fat cows and sheep in the paddocks. I don’t remember the last time I saw so much green pick and clover in amongst the dry standing feed in July, and I have been hearing stories of people getting bogged in their paddocks for the first time in years. After the awful drought and fires we have been through scenes like this make me very happy!

 

          I hope everyone is managing well with all the changes and uncertainty COVID has brought about – we are very fortunate to live in a region that has had few cases and it is easier for us to be socially distant on our farms. Please continue to look after yourselves and stay safe in these strange times.

 

With the rains and the improvement in our seasons we have been noticing a few health issues cropping up.

 

PREGNANCY TOXAEMIA IN SHEEP

Unfortunately, we are still expecting to see cases of preg tox in ewes. In drought we were seeing cases in ewes and cows in poor condition, but this year we are very likely to see cases in fat ewes, especially those carrying multiples.

Pregnancy toxaemia is seen in ewes generally within the last month of pregnancy. At this stage of pregnancy there is a high demand for glucose from the growing lamb/s and clinical disease results when this demand is not met by the ewes food intake – i.e. a negative energy balance develops and a cascade of events of hypoglycaemia, increased fat catabolism and production of ketones occurs.

 

 

Risk Factors for developing Preg Tox:

  • Ewes with multiple lambs are at higher risk than singles – reduced rumen capacity for feed as larger uterus, also increased energy demands of multiples.
  • Body condition score < 2
  • Body condition score >4 (due to reduced rumen capacity due to obesity and advanced pregnancy)
  • Inclement weather or parasite burden causing increased nutritional demands.
  • Inadequate nutrition

Preventing preg tox:

Once a ewe is already sick treatment can often be unsuccessful and expensive. If you are seeing one or two cases cropping up, there will often be more. As is often the case prevention is better than the cure, and there are a number of steps you can take to reduce the incidence:

  • Monitor body condition scores – aim for a BCS of 2.5-3 six weeks before lambing and a BCS of 2-2.5 at lambing. If you have a spread of condition scores, then drafting into smaller mobs to target ewe nutrition will help
  • Scan for multiples and manage these as a separate mob.
  • Ensure a rising plane of nutrition in the last half of pregnancy, but don’t let ewes get over a condition score of 3.5.
  • Supplement feed ewes on poorer pastures. Ewes with singles may need 500g grain/hd/day and multiples 700g grain/hd/day depending on pasture quality. Increase feeding rates during inclement weather. Add calcium and salt at 1% to grain.
  • If shearing in late pregnancy aim to shear multiples first up and have pregnant ewes off feed for as short a time as possible.
  • Avoid any unnecessary stress to ewes
  • Lamb down in sheltered paddocks with good quality feed

CALVING SEASON

In general cows are in magnificent condition this year and are in a much stronger condition to handle calving.

Unfortunately, the good conditions now can be a double-edged sword. Cows that were joined late last year before we got decent rains were doing it tough nutritionally. Under these conditions in early pregnancy the placenta has an enhanced development to compensate for the dam’s low nutrition. This increased blood supply can cause problems at the other end of pregnancy if nutrition is improved and large calves with possible dystocia can be the result. It is important to have cows on a rising plane of nutrition in the last trimester of pregnancy, to ensure newborn calf health and calvability however care must be taken to ensure cows do not become over conditioned (>BCS 3).

Monitor the BCS of your cows during the last 3 months of pregnancy and monitor closely over the calving period.

We have attended dystocias due to oversized calves this season in both heifers and large cows. It is important to monitor both your heifers and your cow mobs closely.

Best results for vets visiting dystocia calvings happen when we are called early rather than later. If you are unable to deliver a calf after 20 minutes of trying, or you are unable to get the front legs delivered past the knees using a calf puller then these are indications to stop and call us. With cow prices as high as they are, it is a good investment to call us out early rather than once a cow is exhausted.

 

MACROMINERALS

As we start to get a bit of greener pick coming through grass tetany (low magnesium) and hypocalcaemia can be a risk for both sheep and cattle. Steps to help reduce the risk of these occurring include:

  • Manage older fat cows separately as a high-risk group.
  • Identify high risk paddocks (e.g. Pastures high in potassium, exposed to inclement weather) and graze these with low risk stock (e.g. steers, wethers).
  • Allocate cows to clover dominant (>20%) pastures if grass tetany is a concern.
  • Provide hay, straw or silage to reduce rumen flow rates and thereby increase absorption of Magnesium and Calcium (this also enhances the flow of sodium and phosphorus in saliva to the rumen).
  • Provide shelter against inclement weather.
  • Supplement with magnesium and calcium (e.g. as a loose lick with calcium and salt, added to grain or white cotton seed, sprayed onto hay). I don’t recommend lick blocks used on their own as there is great individual variation in consumption to give consistent protection against grass tetany. Add dicalcium phosphate to licks if pastures aren’t supered as this provides phosphate as well as calcium
  • For ewes to prevent hypocalcaemia ensure a rising plane of nutrition at the end of pregnancy and pay particular care with multiples.

 

                                   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

116 Bridge Street, Uralla 2358

02 6778 3133

info@urallavet.com.au

www.urallavet.com.au

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