CASE NOTES
Early weaning lambs & calves
2018 drought experiences
Jillian Kelly, District Veterinarian Coonamble & Scott Parry, North West Vets
Posted Flock & Herd December 2019
Introduction
Early weaning is a powerful drought management tool that can be used to influence nutritional, reproductive, animal health, behavioural, logistical and environmental factors associated with breeding sheep and cattle operations. The ultimate success of any early weaning process is dependent on the nutritional management, livestock handling and animal health treatments that are used in the process.
Nutritional and Reproductive Benefits for the Ewe / Cow
The amount of energy required to feed a lactating dam and progeny exceeds that required to feed a dry dam and weaned calf or lamb by 30-40%. It is therefore, more economic to feed them as separate units rather than together.
Additionally, an early weaned cow or ewe has a much better chance of regaining body weight and fat stores and getting pregnant again than a lactating female who is putting energy into feeding a big lamb or calf.
It is more cost effective to maintain animals at a constant or near-constant body weight, rather than let them slip in condition and then build them back up.When body fat is mobilised it relinquishes 28MJ of energy. To put on 1kg of body weight, it requires 34MJ of energy. So it is much more energetically inefficient to lose weight and then put it back on, rather than maintain weight. It is ideal to early wean calves or lambs before the dams slip below fat score 2.5 (2 at an absolute minimum) in order to get them back up to 3 before the next calving or lambing.
In cattle, if early weaning occurs prior to Christmas either prior to or during joining, there are reproductive benefits and better conception rates. This is because cessation of lactation breaks the postpartum anoestrus and causes cows to cycle and ovulate.Despite the dry weather and prolonged drought feeding that has occurred, many producers who early weaned achieved 90%+ pregnancy diagnosis rates, which is higher than many of them achieve in a normal season.
Animal Health Considerations for the Weaner
It is recommended to weigh a selection of animals and only wean those calves that are more than 80kg, and those lambs that are more than 15kg. While calves and lambs have been weaned lighter than this, they require a lot of careful management and the morbidity and mortality rates are much higher.
It is preferable to do all invasive management procedures to the weaners (such as marking, tail docking lambs and branding calves) several weeks in advance so that they are able to heal while on their mothers. If this is not possible, wean, wait several weeks until they are accustomed to the weaning environment and then do these procedures. Pain relief should be considered (for example topical pain relief as well as oral or injectable NSAIDs). The weaning process needs to be as stress free as possible to get good success rates.
Give a second vaccination for clostridial diseases at weaning (assuming the first dose was at marking). This booster dose will confer full immunity for 12 months and can be given as soon as 4 weeks after the initial dose.
Consider other vaccinations for diseases such as pestivirus, vibriosis, leptospirosis in cattle and erysipelas and campylobacter in sheep, depending on disease risk and farm management practices.
Considering the experiences of the 2018 early weaning process under the extreme drought conditions, a vaccination for respiratory disease and pink eye in calves is strongly recommended.
The prolonged dry weather has seen many cases of low Vitamin A and E levels in both sheep and cattle diagnosed across the district. An injectable dose of Vitamin ADE is recommended at weaning, and every 6 months thereafter while there is no green feed available. The injection can cause pain on injection and subsequent lameness in low body weight livestock so site selection and following the labelled instructions is essential.
Management Considerations for the Weaner
In many cases where early weaning is preferable there is little standing paddock feed of any nutritional value, and so early weaned animals will be managed in a feedlot .This is of benefit from a management point of view (it is easier and less labour intensive to feed groups of animals all together) but can bring about its share of animal health and management issues associated with confining young animals.
Animals should be imprinted by being fed grain while on their mothers. This can be done easily by feeding as little as 50g per head for three feeds with their mothers prior to weaning.
Separating stock on body weight is very important to success. Having a group of animals that are all of similar body weight s is far more important than the number of animals in each mob.However, aim to have no more than 400 lambs or 100 calves in each group a maximum. Smaller mobs will have better success rates.
When weaning calves, allow 3cm per head of trough space for water, 40cm per head of feed trough space and 2.5 square metres per head of pen space.
When weaning lambs, allow 2cm per head of trough space for water, 15-30cm per head of feed trough space or if using self-feeders 3-5cm of access per lamb and 2.5 square meters per head of pen space.
Ensure that feed and water troughing is an appropriate height and width for the early weaners. There have been multiple cases during 2018 where early weaners did poorly because the troughing was too tall for the small animals and they struggled to eat. Animals prefer to eat from near ground level.
Water cleanliness and quality is important. Water should be at least 10m away from feed sources to reduce contamination of the water with feed. Troughs should be cleaned daily.
By allowing plenty of room, plenty of trough space and groups of animals of similar body weights, you will reduce bullying and optimise feed consumption and growth rates. Having said that, you will still get around 5% of early weaners that will be shy feeders. They will refuse to eat grain, will sulk and hang in the corners of the pen and do poorly. These animals need to be identified, removed from the pen and put into a pasture paddock, or a special pen for shy feeders with good quality hay and a small number of animals.
While on one hand it is better to leave animals in the one social group together, on the other it is best to run animals of similar body weighs together.From the experiences of 2018, it is best that animals are re-sorted every 2-3 weeks and re-classed on body weight. It seems that in every mob there are some animals that do really well and end up bigger, and some that tail off and do poorly, so even though they were drafted on body weight initially there is now a disparity that will be best corrected by redrafting regularly.
The timing of weaning was also important in some cases. Animals weaned in the really hot or wet weather did poorly. It is worth looking at the weather forecast and trying to plan for a settled weather period in which to wean.
The success of early weaning comes down to a bit of TLC (Tender Loving Care). The most important part of this TLC is observation by the farmer. If they can take the time to walk through the pens daily and look for sick animals, shy feeders, feed consumption or wastage and the colour and consistency of the faeces, many early weaning problems can be offset before they take hold of the mob.
Nutritional considerations for the Weaner
Nutritional management is vital to the success of the early weaning program. There are many different ways to feed weaners but the basics include a cereal grain base with a protein source (pulse grain or protein meal) added, plus ad lib. good quality hay. One example of a diet for early weaners is barley with cracked lupins plus ad lib. good quality hay. Another example is commercial weaner pellets and ad lib. good quality hay.
Better results will be achieved with cracked or rolled cereal grain for weaning calves, however is not necessary for lambs. Whatever is fed, it must be palatable, with similar particle sizes. Weaners can be fussy and particularly sheep can sort grain mixes. They will often prefer to only eat the soft, palatable cereal grains and leave behind the hard pulse grains or the bitter buffer pellets. When checking the pens, ensure that the feed troughs or self-feeder trays are checked to ensure that the animals are eating the entire mix.
The requirements of the animal will vary depending on their body weight. The energy component of the diet should be as dense as possible. A good target is 12MJ ME/kgDM or better. The following table gives the protein rates for each class of stock:
| Weight | Protein requirement | |
|---|---|---|
| Calves | Lambs | |
| 80 - 140kg | 15 - 22kg | 16-18% |
| 140 - 200kg | 22 - 30kg | 14-16% |
| 200kg+ | 30kg + | 12% |
Feeding twice per day is advisable early in the weaning process. This allows careful feed allocation based on needs and prevents gorging and acidosis. It also allows the feed to be introduced and increased slowly over time. Once the animals are on a full ration and the shy feeders have been identified they can be switched over to self-feeders or other feeding systems.
Many cereal grain based diets are low in calcium and sodium. Ensure that lime and salt (or an alternative commercial product) is included in the diet. This can be done by adding 1% limestone and 0.5% salt to the grain mix; or alternatively mixing lime and salt at a 50:50 ratio and putting it out in drums around the weaning pens.
Coccidiosis was an issue in a number of mobs of early weaned stock during 2018. Consideration should be given to including a coccidiostat in the diet, and to the provision of feed up off the ground with little spillage to avoid faeco-oral contamination.
The first 2-6 weeks (depending on age at weaning) of this process should be viewed as an early weaning process, not a feedlotting process. The aim during this initial phase is not to achieve maximum growth rates. It is to keep animals alive and healthy, and going forward. Even if it is just a gain of 50g/hd/day, animals that go forward constantly have a better chance at survival and health than those animals that go backwards and lose weight during the process. After the first 2-6 weeks and the animals are settled, healthy and gaining weight, the process can then be viewed as feedlotting when weight gain can become the primary aim if required to meet targets. A reasonable target for cattle is 0.5-0.7kg/head/day over the whole process and for sheep 150-200g/hd/day.
POTENTIAL PROBLEMS ENCOUNTERED
While many of these have been already mentioned, it is worth listing the common problems encountered during the early weaning process during 2018
- Pink Eye - in both sheep and cattle.
- Respiratory disease - in both sheep and cattle. This was bacterial or viral pneumonia, but also due to heat load during the 10 days over 42°C experienced during January 2019.
- Grain poisoning.
- Shy feeders.
- Clostridial disease.
- Nitrate poisoning from introduced hay.
- Coccidia.
- Salmonella.
- Water belly in wether lambs during extremely hot weather in January 2019.
- Reduced feed consumption during wet or hot weather.
- Lack of a market for stock even after feeding for a prolonged period.
- Producers failing to do feed budgeting and planning.
Conclusion
The aim of the early weaning program should be:
- To improve the efficiency of nutrient use in both the dam and progeny
- To increase the reproductive capacity of female breeders
- To avoid animal welfare issues of females becoming poor and weak
- To reduce environmental degradation of paddocks
- To maximize efficiency of labour use on farm
- To produce calves and lambs that are quiet, well handled, have a strong immune system, a well-developed gastrointestinal system and that continue to grow at a moderate growth rate to achieve saleable or herd outcomes.
Acknowledgements
The LLS District Veterinarians, Land Services Officers and DPI staff who have imparted knowledge and experience on this subject, Geoff Duddy and Paul Cusack for all of their wisdom and informal chats on the subject and the producers who hosted and participated in Early Weaning smoko sessions across the region throughout 2018.
References
- Cusack, P. Centre for Veterinary Education Distance Education notes. Ruminant Nutrition. 2014
- NSW DPI, Managing & Preparing for Drought, 2018