Many sheep producers and their flocks wished they were in Sochi to avoid the recent hot spell. Not only to enjoy the Olympics, but to reduce the impact of heat stress on ewe and ram fertility and lamb viability.

It is understood that fertility is affected when sheep experience temperatures over 41 degrees Celsius for greater than 9 hours on the mating day or for 3 days after mating. This reduced fertility is due to early embryonic mortality. In our region it is expected that most of the early December joined ewes will be pregnant by now, however the ewes being joined in the last week of January are at risk of suffering embryo mortality.

Every ewe that slips one cycle because of heat stress needs another cycle to conceive. When heatwaves 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 rejoining in 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 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 weaning 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.

Call us to find out more.

On an animal basis, biosecurity is just a big word for keeping unwanted bugs out of your herd.

In general, our extensive cattle and sheep industries have poor biosecurity. The pig industry generally is fantastic – they appreciate just how costly some of the bugs can be if introduced.

Steps that are vital if you are serious about biosecurity are:

• Know the current status of diseases in your herd or flock
• Identify the diseases you don’t have that you definitely do not want to get
• Make a plan on how to keep these diseases out
• If you identify diseases you are better without that can be eradicated, consider eradication from your herd
• Also consider biosecurity between groups on your farm. Young stock are often best kept well away from mature stock. Equipment used is also a source of contamination between mobs.

In cattle the diseases that we see that cause the most problems if introduced to a herd that does not have them are:

• Pestivirus – abortions, still-born or unthrifty calves, abnormal calves, mucosal disease, lowered fertility
• Strep agalactiae – a highly contagious mastitis that puts the cell count way up and causes lots of clinical mastitis

In sheep, the main culprits are:

• Drench resistant parasites
• Footrot
• Johne's disease
• Lice

Generally, diseases come in with animals. Therefore maintaining boundary security and buying wisely are the most important steps.

Just remember – even one apparently healthy looking animal can end up costing you thousands in lost productivity if it is carrying something nasty.

A great website has been designed by Animal Health Australia & Plant Health Australia to help you design a biosecurity plan. See www.farmbiosecurity.com.au for more information.