Growing weaner cattle during winter

You have done all the hard work with last year’s spring calves, grown them through to weaning, carefully yard weaned them and given them the necessary health treatments. Now it’s time to reap the rewards and capitalise on the current good prices.

What is your plan to get them through the rest of winter and make the most of when the pasture takes off in spring?  With the current prices of young stock making $4.00 to $5.00 per kilogram liveweight in the store markets, it can be very profitable to ensure your weaners grow at a steady rate during the winter months.  A well-managed weaner could be 50-100kg heavier by the end of spring if they have had the right feed and nutrition during winter.

How can we make sure that our spring born weaners perform at their best through the winter, and is it worth adding supplements to chase higher growth rates?

For any pasture-based finishing operation there is a need to balance the likely feed supply against the feed required. Matching the number of animals to the available grazing area is a key decision and enables any deficits in supply to be filled with supplements. A follow on from this is that we need to match the pasture rotation (the length of time a pasture is spelled after being grazed by stock) to the growth rates of the pasture. Having the ‘right rotation’ is critical to optimising pasture and animal performance. As a starting point it is suggested that animals enter a pasture at 2400 kilograms of dry matter per hectare (kgDM/ha) and graze it down to 1200 kgDM/ha.

Over winter when pasture growth rates are low the goal should be to have a 35 to 40 day rotation around the weaner grazing area. If you are grazing a paddock for three days before stock are moved, you would need 12 paddocks to get the 36 day rotation. If you only have six paddocks you can compromise by adding in supplements and shift weekly or run an electric wire to halve each paddock to enable the three day shift. A longer rotation period gives pastures more time to recover post-grazing to reach the target height before being grazed again.  As we move into spring and pasture growth rates start to increase the grazing rotation can be shortened, as it takes less time for the pastures to recover to the desired height.

Grazing a pasture from 2400 kgDM/ha to 1400 kgDM/ha over the three day period will keep some leaf area on the pastures and encourage good regrowth. To achieve the goal of animals entering a high quality pasture of 2400 kg DM/ha, the pasture needs to be of good quality containing improved pasture grasses and clovers and hopefully some autumn saving will have built a feed wedge before the winter set in. If the rotation speeds up or the weaners are hungry before the next scheduled shift or are grazing the paddock too hard (below 1200 kgDM/ha), then a supplement will need to be added to the diet for optimal growth rates.

As much as we would all like to have 2400 kgDM/ha on offer when putting stock into a paddock, it’s often not possible at this time of year, as some areas have very low autumn/winter growth rates and some grass species grow slower than others and have varying leaf emergence rates. The most important consideration is that weaners are adequately fed for every day of winter regardless of whether the feed is coming from quality pasture or a mix of pasture and supplement. Remember the cheapest feed that you have on your farm is the quality pasture you grow yourself so it’s always good for home grown feed to formulate a large percentage of the diet.

Supplements can be used as a tool to balance up the animal’s diet and to lengthen the grazing rotation ensuring pasture is available throughout winter. Essentially adding supplements into the system enables stock to stay where they are for longer, giving the grazed pasture more time to regrow prior to being grazed again.

If a supplement is needed, consider your cheapest energy options. A quality pasture hay or silage may do this and if the grass fed market is not your target, then a grain or grain mix or pellets (formulated for growing youngstock) could provide extra energy cost effectively. Care should be taken to transition young stock onto a grain supplement as this takes careful management. (Beef Book Focus: Ch. 5 Choosing Feeds or Beef Cattle Drought Feeding Guide – PDF Format). Consider costing out a grain free pellet or northern clover hay if you are targeting the grass-fed market. Other safe options are vetch or oaten hay as a supplement for weaners on quality green pasture or crop. Weaners on a lush crop or young fresh pasture may benefit from the fibre content in the vetch, oaten or pasture hay.

A winter pasture where all the grasses are growing leaf (vegetative growth stage as opposed to reproductive growth in late spring) will have the required protein of all weaner stock classes. This pasture will also have enough energy on a per kilogram of dry matter basis. The issue with winter pastures is typically not having enough feed on offer. The quality will be good, but often the quantity of energy available will be lacking, so when pasture is limited, an energy supplement is needed to lift animal growth rates. Vegetative winter pastures are typically low in dietary fibre, thus the feed moves through the digestive passage quickly. A high energy more fibrous supplement may be a good option in this case, although there is still debate on the production and profitability of the addition of fibre to these pastures.

There is no reason why you cannot run bigger mobs in bigger paddocks and still have a 36 to 40-day rotation. In larger mobs it is important to draft off the tail of the mob, being the smaller, lighter weight or younger weaners.  These will be the shy feeders that get the last feed from the supplement if offered or may be bullied by the more dominant animals in the mob. You could consider drafting off the smaller weaners and giving them priority pasture and/or additional supplements. Do the sums and it may be a profitable option to sell these in the store market for a quick return.

Monitor liveweight and aim for a 0.75 kg liveweight gain per day from weaning to joining at 15 months of age. For example, a seven month old heifer weaned at 250 kg liveweight growing at 0.75 kg per day for the next 240 days gives a joining weight of 390 kg at 450 days of age. This is more than adequate for a young heifer to cycle. Your steer calves may be slightly heavier live weight at the same age thus not far from feedlot entry weight. Implement an animal health program so the animals receive an annual 5 in 1 clostridial disease vaccination. Monitor worm egg counts (WEC) and if needed administer internal parasite control treatments to give your weaners every opportunity to reach their target.

Assessing how well the pastures on your farm will deliver the targeted animal performance of say 0.5 kg, 1kg or 1.5 kg/hd/day is a difficult skill – it’s impacted by pasture availability, quality and growth rates – not to mention other animal factors such as genetics and health. While it’s still essential to assess pasture performance and set some targets for available feed and the pasture rotation, there is nothing like running a group of monitor animals over the scales to check that the intended growth is being achieved.

At the end of the day, the growth rate of your animals is up to you – you can have animals growing at 0.5 kg per day or you can add supplement and achieve higher growth rates. Deciding IF you should be chasing higher growth rates then becomes a matter for a simple cost-benefit analysis, but at least you are making informed decisions about what is happening on your farm. With attractive sale prices, it might just be worth rerunning some sums of what is and isn’t worth spending on growing your stock through the winter in readiness for the coming spring