A Winter Boost for Beef
Given the relatively poor state of pasture over winter, many beef farmers accept negligible growth rates for their cattle by default. And yet, even in the face of low pasture quality there's every reason why meaningful stock growth can be achieved. If you're interested in doing just that, then read on.
There’s no two ways about it, winter pasture offers cattle little or no chance for growth. Bare maintenance is often where it’s at. For the farmer, the financial return on their pasture over the winter is about as poor as it gets. All hope is vested in the vitality of spring pasture to rapidly finish the animals for a good sale.
De-stocking can be an option. While you’ll miss out on premium spring prices, it can be useful in mitigating any damage to wet pastures from pugging and compaction.
SealesWinslow Science Extension Officer, Paul Sharp, suggests looking beyond ... towards growth. His advice is to draw on the cheapest feed source first, but also to scrutinize it with a focus on quantity and quality. “Even if you have reasonable crop availability, it will likely be deficient in vital nutrients and minerals, leading to lower feed intakes and reduced growth rates,” Paul notes.
He makes a compelling case for supplementing with good-quality feed and offers realistic examples. Adding pasture silage, for instance, (see box, example 1) results in good improvements. However, the actual rate of growth will be limited by the available nutrients or minerals. Adding trace elements therefore makes sense; this is ideally done with a lick block that also promotes forage intake.
Where animals are fed on low-quality winter pasture, Paul recommends improving the nutrient level by adding a high-energy pelleted feed (example 2). This is a very efficient way to boost animal growth.
“It’s also prudent to examine your grazing strategies and their effect on overall quality of the pasture,” adds Paul. “If, for instance, inadequate grazing patterns, such as under-utilisation, resulted in poor pasture, then you’d best rectify that first.”
All in all, winter cattle growth is eminently achievable.
Feeding Fodder Beet
Fodder beet is increasingly popular as a winter feed for beef stock. However, it does have some nutritional constraints, including a low phosphorus content, low fibre level (<20%) and less than optimal protein content (13%). It does have a high sugar content, which makes it very palatable.
Feeding silage and straw alongside fodder beet to ensure the animal's energy needs are met and helps to offset fibre and protein shortfalls. However, a phosphorus deficiency may remain.
Fodder beet has a low phosphorus content, low fibre level and less than optimal protein content. On the other hand it has a high sugar content, making it very palatable.
Cows grazing fodder beet ingest more soil than cows grazing pasture or other non-bulb crops. New Zealand soils contain reasonable levels of iron, so when cows are grazing fodder beet, their iron intake increases. Iron is an antagonist for many trace elements - in other words, it interferes with the normal metabolism of those trace elements.
Copper absorption in particular is decreased in the presence of high dietary iron, most likely as a result of insoluble compounds forming in the rumen.
Phosphorus is a major component of the skeleton. It also plays a key role in a number of metabolic processes, including those that take place in the rumen. It's needed for bone strength, energy metabolism and milk production. It's also involved in buffering the rumen, which helps to minimise the risk of acidosis.
Cows that are fed a low-phosphorus diet for an extended period of time may develop sub-clinical phosphorus deficiencies. Symptoms of low-grade phosphorus deficiency include reduced appetite and rapid weight loss; in some cases, blood may be seen in the urine.
The effects of a low-phosphate diet are not immediately obvious, as in the short-term cows will mobilise their existing phosphorus reserves to maintain blood phosphorus levels.
Lactating cows require a dietary phosphorus intake of between 0.3% and 0.4% (i.e. 3.0 - 4.0 g P/kg DM). Dry cows require a slightly lower level (0.27 - 0.35%).
Phosphorus supplementation has been associated with an increase in fertility. However, the mechanism underpinnning this is uncertain. It may be a result of weight gain, reduced weight loss, or a direct effect of the phosphorus itself.
Heifers that have a phosphorus deficiency may experience delayed oestrus. In addition, cows with a prolonged sub-optimal phosphorus intake may show a reduction in milk yield.
Animals are typically wintered on fodder beet for 60 to 100 days. Grazing on a predominantly low-phosphorus diet for this length of time could result in phosphorus deficiency manifesting at calving or early lactation, which would have implications for the health of young stock.
While some cows that experience phosphorus deficiency will recover, others will go down. The classic presentation of a cow that has gone down as a result of phosphorus deficiency is a 'creeper cow' - the cow is down but alert. Such cows will try to crawl around, especially on their forelimbs, but will be unable to rise. The fact that these cows are alert and energetic distinguishes them from the sluggish downer cow seen in milk fever.
Whether you farm dairy or dry stock, raising strong, healthy calves is vital for the future of your business. Doing this successfully requires growth targets, regular monitoring and an appropriate feeding strategy.
In order to perform well, young stock need to reach their target weights on schedule. Beef cattle that get to their target weight on time can usually be sold for a better price than those that lag behind. Dairy cows that are raised well as heifers are more likely to have good reproductive performance than heifers that have been slow to develop. They are also more likely to reach their milk production potential.
Setting target weights is important. For male beef calves, the target should be based on your desired sell date: work back from there to determine checkpoint targets. Heifer calves that are going to be mated at 15 months should be 30% of their mature liveweight at weaning, and 60-65% at mating. Given that an LIC study conducted in 2012 found that 53% of heifers were more than 5% below their 6-month weight target, it’s clear that we have room for improvement.*
Once you have set target weights, you need to monitor stock progress. While it’s easy just to guess or go on age, it’s not very accurate. It’s worth investing in a set of scales and weighing calves on a regular basis to see if they are on track. The DairyNZ website contains targets for young stock at 3, 6, 9, 15 and 22 months.
A set of scales will also help to ensure you don’t wean calves when they are too light. Friesian calves on restricted milk and adlib meal can be weaned after they reach 63 kg; calves on a high-milk system need to be 75-80 kg at weaning.
To keep your calves on track, aim for steady growth; an adequate supply of suitable feed is an obvious essential, but keeping stress to a minimum is also important. One stressor that’s easily overlooked is, in fact, the feed. Abrupt changes to the feeding regime can cause growth checks, as calves take time to adapt to new feeds.
You can reduce the impact of new feeds by introducing them gradually, slowly reducing the proportion of the old feed and increasing the proportion of the new one. Minimise the number of changes at each step in the transition, e.g. if changing from muesli to pellets, choose pellets that smell and taste the same as the muesli. That way, the calves only have to get used to the new texture.
To make sure that calves wean successfully, focus on getting their rumens well developed. Feeding a quality calf starter containing 20% crude protein will help. Once they are on pasture, continue feeding them, gradually decreasing the meal allowance. Monitor stock growth to ensure they are meeting their targets and if weight gain is not on track, consider altering either the type of feed or the quantity allowed.
Rearing Young Bulls
Much emphasis is placed on rearing good quality calves from birth to 100 kg. Attention is paid to management, health and nutrition and in the majority of cases, weight targets are monitored. Unfortunately, between reaching 100 kg and getting to the point of finishing, this can wane and targeted body weight gains may not be reached.
Any transport that occurs when moving from property to property can be a stressful experience and can cause growth checks. The same occurs when a group of animals are formed and a new hierarchy has to be established at the grazing property. Transportation stress has been shown to increase cortisol levels and increase numbers of neutrophils. When stress occurs, it disrupts the normal functioning of the animal and in cases, can lead to illness. In addition, the energy and minerals needed for stress response are then not available for normal growth needs.
Calves coming on to a property should be weighed as early as practically possible. This gives a base line for further weights through the growing period and also helps identify if there are any smaller animals under 100 kg. If sufficient good quality pasture or silage is available, it may not be necessary to continue supplementary feeding throughout the time animals are on farm. These forages can more than meet the needs of growing animals. Minerals are however often lacking at this time. The dry matter requirements are met from pasture but a deficiency of essential minerals can limit growth rates. These minerals are needed on a daily basis and so should be supplemented daily. These can be provided via the water or from a mineralised molasses block.
In times of drought or other feed shortage, additional pelleted feed is an option to ensure animals keep up to their weight targets. As with all groups of animals, there will be a tail, animals that are not performing as expected. With regular weighing and a targeted growth plan, the tail can be grouped together. This allows for strategic use of additional supplementary feed. These animals can then be put back with the rest of the herd once they have caught up and if necessary, a new tail group formed. A budget should be set to feed 1-2 kg of a transition / weight gain pellet. A diet containing moderate amounts of NDF, starch and protein is ideal; as is one including a vitamin and mineral premix.
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