In the second in a series of columns, scientist Jim Gibbs discusses achieving and maintaining maximum intakes in beef cattle in winter beef finishing systems.
By now, most farms have transitioned the cattle to the beet crops. If you haven’t, you should have, because it is harder to do so in wet and cold weather, and liveweight (LWT) gains on autumn grass are typically poor, while gains on beet are good. Cattle should be transitioned to the point where they are eating as much beet as they can, as discussed last month, and this will take between 14 and 21 days with young cattle. By the end of transition, they should also be on a low supplement intake.
The most important rule: good LWT gains are only achieved by maximum intakes of beet (not supplement). Everything you do from sowing should serve this purpose – your paddock design should give space and time to cattle eating; your cultivar should suit your cattle; your agronomy should deliver lots of good leaf; your transition should be a time of steady increase in intake; your supplement strategy should give the cattle no surprises and not reduce beet intake; and your daily management should make sure cattle can always eat more.
To achieve and maintain maximum intakes of beet after a good transition, assuming you have a good paddock design with access to both beet and supplement, it is only the last two that are under your control – supplement strategy plus beet allocation. From this time of the season, they are the most important, and they are the most common mistakes.
Eating supplement is easy, and eating beet is harder, and they will stand at the supplement until they feel full and you are broke.
In beef systems, cattle need to eat (note: not be allocated) 1kg drymatter (DM) (weaners to 400kg LWT) or 2kg DM (R2 cattle 400kg plus LWT). To maximise beet intake, the supplement must be: a: actually eaten and b: limited to these amounts.
What goes wrong with supplements? Most commonly, too much is given out – if you give it, they will eat it. Eating supplement is easy, and eating beet is harder, and they will stand at the supplement until they feel full and you are broke. The more supplement they eat, the less beet, and even an extra 1kg DM smashes your profit.
You need to decide for them – and allocate the amount that lets each animal eat their 1 or 2kg DM. In wet pastures, utilisation may be 30% – so they need 3kg allocated to eat 1kg DM, but in dry conditions with lucerne silage fed behind a wire, utilisation may be 90%. So work it out carefully, because too much and too little have the same effect – LWT gains slump.
How you feed the supplement matters – bale feeders will typically reduce LWT gains by 30% because you can’t control intakes to low and even levels. For example, a 200kg DM medium round bale should feed more than 180 weaners. We can argue about how many weaners will get around a feeder, but we’ll all agree it isn’t 180 all evenly eating their 1kg DM. Some eat 5kg by being there all day, some never get near it and eat zero. If you then increase the bale feeders, you have increased the daily allocation – too much supplement. The only way to make bale feeders work for maximum LWT gain is to allow one per 25 cattle, then hotwire them off and only allow the cattle on for about 30 minutes to an hour a day, and check over a week or so that the right amount is being fed.
It is far better for LWT gains to use grass or autumn-sown oats strip-grazed across the autumn and winter. Some places can’t, it is just too wet, but the best systems use this. The next best option is to feed supplement in a line behind a wire, and if you use the same line for a week then utilisation even in wet weather is typically still >75%. In very wet places, you can put out silage once or twice weekly in a line, enough for the days, then hotwire it off and let them on it for 30 minutes to an hour each morning, like a self-feeding face, then hotwire it off again.
So, if your supplement is right, the next important management is beet refusal. Beet is unique in feeding – unlike kale, pastures or cereals, maximum intakes are not achieved at the cost of greater refusals. Maximum intakes have been repeatedly measured with utilisation above 95%. The trick is that the beet is eaten over three days, and to achieve maximum intakes of beet, you must have 20%-plus refusals of bulb at 24 hours, 10% at 48 hours, and 5% at 72 hours. So, if you can’t see three days’ break behind you, you haven’t left enough.
This is the most common LWT gain problem with beef on beet (it is different with dairy). Most farmers new to beet rightly want to limit refusals to ‘clean it up’, like brassicas, because with brassicas once it is behind you is lost. Beet is different – they will leave very little leaf, and cattle eat the bulbs for 60 days after they are uprooted, so they aren’t lost. If you limit them, you crash intakes and LWT gains. To get an idea to start, kick over every fourth bulb and see how much that is, and aim for that at 24 hours refusal.
Good beet management for beef is subtle changes – and it is harder than it first looks, with most farmers needing a year or two to get on top of it.
