By definition, early weaning is weaning calves at an age younger than 'normal' practice. In Queensland, the normal range of weaning is at 5-8 months though the range does extend either way by a couple of months in certain environments. In extreme cases, 'early weaning' (without milk replacer) can be performed safely and effectively down to 4-6 weeks of age, though calves that have reached 3-4 months are considerably easier to feed and manage.
The main purpose behind early weaning is the proactive management of breeding herds in times of feed scarcity or drought. During these times, late pregnancy and lactation (particularly 2-3 months post calving), can have a drastic effect on the body condition of cows, particularly first calf cows. This will result in severe weight loss, low subsequent pregnancy rate, poor long term calf performance and possibly significant breeder deaths in extreme conditions. Importantly, the latter could render producers liable for prosecution for welfare concerns under the Animal Care and Protection Act 2001.
Producers should also consider the additional damage that is being done to pastures.
This leaves graziers with the following management options:
- feed very large amounts of fodder to keep cows and calves going
- early wean and sell bobby calves
- early wean and feed calves separately to the cows.
Note: Calves weaned early must be fed and managed well.
Benefits of early weaning
Typically it is easier and cheaper to feed a young calf (weaner) and its mother separately, than it is to feed a lactating cow/calf unit.
In extreme conditions, early weaning is usually the best option for a range of reasons:
- The feed requirement of a dry cow is often only 50-65% of a cow with calf at foot.
- Very young weaners eat relatively small quantities of feed which often reduces the total labour input involved with feeding.
- Well fed and managed early weaners will perform just as well later in life, as normally weaned calves - starved calves left on cows may not.
- The dry cows can be fed at a dramatically reduced level and cost, and in some instances may not need to be fed at all. If the cows had become extremely poor, they will need a higher level of feeding for a period of time to pick up weight and condition to an acceptable level. Dry cows will typically gain weight quite rapidly on the same feed that they were previously losing weight on, with a calf at foot.
- Cow deaths if imminent, can often be avoided.
- Many more cows will go back in calf in a timely matter.
- Marketing options are opened up. That is, in a drought it is virtually impossible to sell heavily pregnant cows or cows with very young calves at foot. Once the calves are weaned, there is good opportunity to look seriously at further reducing stock numbers. Once cows dry off, they will pick up condition and are easily transported.
It is worth doing some sums to look at the option of production feeding some cows for a short period, e.g. 50 days on grain. This can be quite profitable if there is adequate premium associated with moving up one or two weight and price categories at the meatworks. It also further reduces stock numbers on the property and increases the pasture response from any rainfall received.
Understanding the young calf
It is the stage of digestive tract development which governs how calves should be weaned at different ages.
All calves are born with an undeveloped rumen (the stomach which as an adult acts as a large fermentation vat allowing the digestion of the feeds eaten by a grazing animal). The very young calf is dependent on milk for its supply of nutrients. When a calf sucks, a reflex action closes over the oesophageal tube which stops milk going into the rumen (and fermenting).
As the calf starts to forage, during the first few months, its rumen gradually grows and develops. The rate of development and timing will vary according to factors such as the nutrition, condition and milk supply of the cow, and the available feed in the paddock. Typically, calves may be functioning as normal ruminant animals between 3 and 6 months of age.
If there is one advantage under drought conditions, calves tend to have more developed rumens because they are forced to start foraging younger in life (due to lower milk supply). The feed quality is also poorer, which in turn provides the physical stimulation and bulk to help the rumen to develop.
When very young calves are taken off the cow, the dietary requirements at different stages need to be considered. Typically, early weaned calves will not have a fully functioning rumen, and as such their digestive track operates largely like a monogastric animal (e.g. a pig), depending mainly on the abomasum or fourth stomach. Therefore, once the calf is old enough to be weaned from milk, a grain-based diet which can be readily digested should be provided as the main source of nutrition, as should hay/roughage to ensure the rumen continues to develop normally.
Since the rumen is less developed in young weaners, it has minimal ability to process urea or to break down the gossypol in whole cottonseed. Therefore these are not recommended for very young weaners.
How young can calves be weaned?
The age at which weaning takes place is case specific, and will depend on factors such as:
- severity and length of dry conditions leading up to the time of prospective early weaning
- time of year relative to when rain/storms would normally be expected
- climate outlook for the immediate and longer term
- condition of the cows
- condition of the calves
- amount of paddock feed available and current level of supplementary feeding
- availability and price of feed stuffs both current and future
- time before the next 'dry' or winter season when there will be no or little response in grass growth even if there is substantial rain.
Decisions and plans need to be made in a timely manner to avoid being caught by rapidly deteriorating conditions without the appropriate resources on hand.
In extreme conditions, it is possible to successfully wean calves from 4 - 6 weeks of age without a milk replacer, provided appropriate management is applied. Calves 3 - 4 months of age are easier to feed and manage than younger calves.
What to feed early weaners
Due to the rumen development issues discussed earlier, management and feeding should be considered relative to several age/weight categories. Early weaners should be segregated into management groups where the group spans across more than one category. See also the following section 'Feed Mixes for Early Weaners'.
Weaners: 1 to 4-5 weeks old
The number of calves weaned voluntarily at this age in a beef herd is small, however it sometimes becomes necessary, and there may be a few orphans as well. At this age, the rumen micro-organisms and digestive enzymes of calves are not developed sufficiently to enable them to survive on a non-milk diet. Consequently a milk replacer is required.
It is critical for the long term health of the calf that it receives sufficient colostrum (and therefore antibodies) from the cow in the first six or so hours of life. Where possible, calves should be left on the cow for several days post-calving. As the calves will have to progress to other feeds, it is advisable to allow them free access (ad lib.) to a high energy, high protein, grain-based mix and good quality hay. Intakes of these will be small.
Suggested diet for weaners 1 to 4-5 weeks of age:
- Milk replacer should be fed at about 10% of body weight per day. From about one week of age, calves need only be fed once per day. Calves should preferably be fed via a calfeteria set up or bottle fed, rather than bucket feeding. Remember the teat sucking action is needed to close off the oesophagus to avoid milk getting into the undeveloped rumen where it will ferment. Small digestive upsets in pre-ruminant calves regularly cause scours and potentially, dehydration or longer term effects.
- Ad lib access to a high energy, very high crude protein (18-21%), grain-based ration. Intakes will be very low to low, particularly at the start. There is a range of specialist commercial products available. However, where the facilities and feedstuffs are available, a home-made mix as discussed in a later section, would be suitable.
- Good quality hay (ad lib). This may include cereal hay or good quality forage sorghum, but preferably not lucerne which can be too rich and cause scours. However, the palatability of lucerne can be useful to encourage the eating of solids initially.
Intakes of feed other than milk will usually be very low, but access to them allows the calves to become accustomed to the feeds and to develop their digestive systems.
Weaners: 4-5 to 10 weeks of age
Most weaners will weigh between 50-75kg at 4-6 weeks and 85-100kg at 10 weeks. At this stage, there is generally no need for a milk replacer. A high energy, high crude protein (16-20%), grain-based diet is preferable at this stage.
To ensure normal development and performance later in life, the target weight gain should be as close as possible to what would be achieved on milk in a normal season. This is often around 0.8 to over 1kg/hd/d (less in poorer environments). The minimum target weight gain is around 0.5kg/hd/d.
Suggested diets for weaners 4-5 to 10 weeks old:
- A high energy (12-12.5MJ/kgDM), high crude protein (16-20%), grain-based ration fed ad lib (likely to be 1-2.5kg/hd/d) across the weight range
- Hay or pasture ad lib (normally not more than 1 kg/hd/d). Where available, reasonable quality hay is preferred e.g. good forage sorghum or cereal hay (preferably not lucerne). However, because the primary function of the hay is to develop the rumen, a poorer quality roughage eg barley straw, could be used provided the weaners are accessing sufficient intakes of grain. As straw will be less palatable, starting with a better quality hay will ensure calves start eating more quickly.
Straight vegetable protein meal can be used instead of a grain ration (often providing a higher level of dietary protein), however it will be less well balanced for other nutrients/additives (e.g. minerals, vitamins, Rumensin) and may prove more expensive to feed at the required levels. On a macro mineral scale, vegetable protein meals are regularly low in calcium or low relative to the phosphorus level. Some vegetable protein meals fed as a major component of the diet may cause digestive upsets and are far better suited as a key ingredient in a ration.
Even though many early weaned calves have been eating whole cottonseed fed to their mothers prior to weaning, it is not recommended as a core part of the diet for very young weaners because of the potential toxic effects of the gossypol, and reduced intakes/digestive upsets due to the high oil content.
Molasses based diets are also not preferred for these very young weaners as their digestive systems are typically not well enough developed, thus causing scours. However, if other options are not available, or the molasses mix is only a component of the diet, it can be used. The biggest challenge is achieving a ration that is sufficiently high in energy and true protein (lower energy and protein = lower expected performance).
Urea, while a cost-effective way to increase protein content of rations, cannot be utilised by very young calves and may potentially be toxic. Therefore urea should not be used in diets for very young weaners. See the later section on feed mixes for further information.
Weaners: 10 weeks to 4-5 months
The nutritional requirements of weaners weighing 100kg-150kg are somewhat less stringent in terms of quality, but intakes will obviously increase if fed ad lib.
Suggested diet for weaners 10 weeks to 4-5 months:
- Molasses mix with at least 15% vegetable protein meal and possibly a low level of urea (up to 1.5 to 2.5 kg/hd/d of mix across the weight range)
- Hay or pasture ad lib (approximately 1-2 kg/hd/d). More hay can be fed if desired for a higher level of performance.
Grain-based mixes can be continued for these older calves if it is more convenient or cost effective. At the same levels of feeding, higher growth rates could be expected. The total protein level in a grain mix could be dropped a little compared to a mix suitable for younger weaners, and a low level of urea could be included to provide some of the protein and reduce the ration cost.
Whole cottonseed fed at restricted levels (e.g. 0.5kg/hd/d for a 130kg weaner) could also be considered as a part of the diet. Weaners of this age are regularly fed at higher levels, but responses are extremely variable because the high oil content regularly causes digestive upsets that in turn cause large variation in daily intake. Straight vegetable protein meal is also an option, but again the cost (if fed as the sole source of concentrate feed) may exceed other options.
Weaners: 5 months and older
Typically weaners in this category are considered 'normal' weaners and the level of management required is therefore reduced. However, supplementary feeding is still likely to be required if drought conditions have persisted. Suitable options include molasses mixes, grain mixes, straight protein meal and whole cottonseed. It would be preferable to still target weight gains of around 0.5kg/hd/d until the weaners reach at least 200kg.
Feed mixes for early weaners
Addition rates of ingredients are described as 'percentages by weight'. That is, the percentages of all the ingredients in a mix must add up to 100. For all dry ingredients, the process is quite straight forward, however feeds like molasses are often measured by volume rather than weight. For ration calculation, volumes need to be converted to weights. (1 litre molasses weighs approximately 1.4kg. 1 gallon = 4.54 litres, therefore 1 gallon of molasses weighs approximately 6.56kg.)
The younger the weaners, the better quality the ration should be - particularly the energy and protein content. For very young weaners (e.g. less than 10 weeks of age), the mix should preferably have no urea as a source of protein. Some commercial products will contain low levels of urea, e.g. 0.5%. Vegetable protein meal included at 15-25% of the ration will generally supply the required additional protein content.
Key components of a good early weaner grain mix will include:
- grain (higher energy and better responses from barley and wheat than sorghum)
- maximum of 4-5% tallow or vegetable oil will increase energy content without reducing intake (optional)
- preferably no urea (for weaners less than 10 weeks)
- 15-25% vegetable protein meal (depends on which meal and required protein level)
- 5-10% roughage
- 2% bentonite or 1% bicarb soda
- mineral/vitamin premix with Rumensin (or equivalent that acts as a coccidiostat)
- limestone, salt and perhaps a potassium source, if added calcium, sodium and potassium are not included in the premix.
Molasses alone provides energy only (but is not as good as grain on an as-fed basis), i.e. it effectively has no protein. In the absence of urea, the challenge is to achieve reasonable protein levels by mixing vegetable protein meals into molasses. Whether mixing by hand or mechanical mixer, there is a limitation to how much dry material can be mixed in. Adding grain will replace some of the molasses with a higher starch-based energy source that typically has at least 10% Crude Protein (CP).
From a nutritional perspective, the more protein meal (and perhaps also grain) that can be mixed in, the better.
Suggested mixes include:
- minimum of 15% of a high protein, vegetable protein meal (e.g. cottonseed meal or soy bean meal) + 85% molasses, (20-30% protein meal would be preferred).
- 20% vegetable protein meal + 10% grain +70% molasses
Variations of these mixes can be used. If a mechanical mixer is available, low levels (1-3%) of urea could be added to the mix, for weaners greater than 100-120kg. However, in trials in North Queensland, weaners averaging 100kg have been fed a molasses mix with 3% urea with no ill effects. As the rumens of young weaners develop, they are better able to both utilise urea and to avoid toxic effects.
The presence of a mechanical mixer also provides the option of adding Rumensin, most likely as a part of a mineral/vitamin premix. A mineral/vitamin premix for molasses would preferably not include added calcium (as for a grain mix). Extra phosphorus may be desirable. Where it is too difficult to mix in the required amount of protein meal and/or grain, an option is to feed additional protein meal separately.
Points to note
The level of vegetable protein meal in the grain and molasses based diets may need to be varied slightly depending on the crude protein content of the vegetable protein meal used, the age/weight of the weaners and the level of performance required. Suggested levels of feeding are typically aimed at higher levels of performance.
Other health considerations
Early weaners are more susceptible than other animals to a scouring condition called coccidiosis. The condition causes ill-thrift, scours and in acute cases, death.
Blood stained faeces (scours), straining and dehydration are typical signs of the disease. If calves survive the 5-6 days of the disease, they do become immune, but severely affected calves will remain poor doers. Prevention of coccidiosis through adequate hygiene, nutrition and the use of Rumensin (active ingredient monensin sodium) is always the best approach.
While Rumensin has many favourable attributes, it can be toxic if not mixed evenly. There are some other rumen modifiers on the market which will serve the same purpose (i.e. as a coccidiostat).
Scours can also be caused by other microorganisms and digestive upsets. It is important to provide adequate hygiene and to treat affected animals promptly. Dehydration is common and can be managed through the use of an electrolyte replacer. Treatment for non-digestive upset scours usually consists of a program of oral treatments and perhaps antibiotics.
Young stressed weaners may also be more susceptible to other sicknesses such as respiratory problems and pink-eye. As for scours, these should be observed closely and treated appropriately.
It would be a good idea to vaccinate with the first shot of 5-in-1 at the time of weaning (if the calves have not already been vaccinated). This will provide some early protection from both pulpy kidney (potential risk going onto the grain mix), and tetanus (tends to be more prevalent in yards), as the higher risk pathogens at this stage.
Consult your veterinarian if in doubt about the prevention and treatment of health problems in early weaned calves.
Managing the early weaned calf
The key lies in reducing stress as much as possible. Early weaners are typically much more susceptible to stress than normally weaned calves. Anything that reduces the level of stress in the weaning transition will be beneficial to their performance.
One of the key targets is to get the calves (if more than 4-5 weeks of age), on to an all-solids diet as quickly as possible. Depending on individual circumstances, all, or some of the following, should be considered as techniques to improve the management of early weaned calves.
Train calves to eat supplement prior to weaning
Calves that have had access to any supplement prior to weaning will take to feed more quickly. Many calves in drought situations have been nibbling at the cows' supplement and have at least learnt to eat from a trough. Ideally, access via a creep to the actual early weaner ration, for a week or two prior to weaning, can be beneficial particularly for very young calves.
Provide plenty of opportunity for newly weaned calves to start eating quickly
Calves that start eating quickly will be exposed to less stress, will be less susceptible to getting sick and will perform better. Provide plenty of feeding space and, where possible, provide a variety of feed options.
Anything that encourages the calves onto their early weaner grain ration is a positive. For example, if calves have had access to an alternate supplement prior to weaning, it may be useful to spread a bit of this over the early weaner ration to get them started more quickly.
Even if the longer term plan is to feed the early weaner mix out of self feeders, it can be beneficial to feed out of open troughs initially, to get them started earlier. Be aware that many self feeders, feed troughs and water troughs will be too high for small calves. Building up the area in front of the troughs with old sleepers, gravel or the like, may be required. Ready access to good quality water is also critical.
Feeding a better quality hay (such as good forage sorghum, oaten hay or even lucerne, if available) for at least the start of the weaning period will help to ensure the calves start eating quickly.
Segregate calves by size/weight/pecking order
It may be beneficial to separate and manage differently, calves that are notably smaller, weaker or just lower in the pecking order. This requires another pen with water and feeding facilities. Similarly, as older calves transition through the system, they may be segregated out so that they can be fed a less expensive ration and managed less intensively.
Segregate calves that are sick
Despite all best management, it is likely that some calves may still get very sick, e.g. scours and respiratory problems. Where possible, separate the affected calves and manage them separately to reduce spread of the pathogens. Treatment may be required to get them healthy again quickly.
Keep up the hygiene
Try to keep water troughs clean and feed unsoiled. For example, feed hay in racks and supplement in troughs that are up off the ground. Failure to do so will increase the risk of sickness.
Avoid traumatic treatments
In many cases, early weaned calves will not have been branded prior to being weaned. If this is the case, delay branding, castrating, dehorning etc until the calves are well settled post weaning and preferably living outside the yard environment. If the calves received their first shot of 5-in-1 at the time of weaning, the second at branding will give them full protection.
If the mothers of the calves have had extended periods (minimum of three months) without any green feed, it may worth considering injecting the calves with vitamin A, D and E at weaning. All good early weaner rations will have adequate levels of the required vitamins. Only in cases where the levels have been severely depleted will there be a response to the injection.