Agriculture

Growth of Castrated Steers on Free Range: Wean to Slaughter

Cattle grazed in South Africa encounter numerous environmental stressors but they are expected to grow to a certain weight to be economic in abattoirs which is simpler under feedlots but tougher under free range. Growth to market weights before set ages are critical to beef enterprises and it also mitigates carbon contribution. It is recorded that estimates of the magnitude of CO2 reduction based only on an increase of average daily gains from 0.2 kg/head/day to 0.4 kg/head/day and from 0.4 kg/head/day to 0.6 kg/head/day suggest methane emissions would be reduced drastically. Therefore, On-farm improved productivity leads to reduction in methane emission by cattle which is good for the issues of climate change. 

In retrospect, Woolworth Free Range (WWFR) beef market specification set a new expected beef growth performance. It requires animals’ on-hook to be weighing 200 kg (approx. 400kg live), actually, they pay better when it is 240kg (approx.480kg live) before the sixth teeth are fully develop or around 36 months. South Africa beef recording schemes tracks growth until 18 months and left a gap of growth performance until 36 months. The High Value Beef Partnerships (HighVBP) project presented an opportunity to record growth of smallholder farmer’s cattle from weaning to slaughter. The HighVBP recruits and support smallholder farmers to farm to meet WWFR beef specifications with or without 1% concentrates supplementations. Our desktop projections during the planning stages were faced with no data to benchmark the growth rates of cattle on free range. Free Range beef specifications allow 1% concentrate supplementation and this also presents another dimension of knowledge gap on growth rates of these animals under this nutrition regime.  

The study projected that for the animals to reach this weight they need to be growing at 0,5kg/day throughout their growth stages as in a simulation presented in figure 1 below. Figure 1 shows that from birth to wean we expect growth of up to 1kg per day but then slows down to 0,4kg after 24 months when they are just on range. So farmers in HighVBP needs to keep their herds growing at this rate to meet the market specification. The figure below depict an ideal situation at which they must grow. But increasing the growth rates to 0.6 – 0.8 kg/day would allow those same animals to be slaughtered between 18 months and 2 years of age or they could be retained to older ages at substantially higher slaughter weights, thereby earning even higher premium prices.

Figure 1 Expected growth rates to meet the target weight before sixth tooth stage

The study tracks growth of over 200 castrated steers on different farms. This past years 91 steers were slaughtered from two farms and this is worth sharing with the farmers. The farmers in both cases supplemented their animals with 1% concentrates of their daily intake during the dry season and during the finishing stages. At the beginning of the FR specification cold carcass weight of 180kg was accepted until May 2019, when it was increased to 200kg. Figure 2 below, shows growth rates of individual steers on each farm. To note is that from month six to thirteen there was high growth and most gained over 110 kg in that period. The period was followed by no growth and loss until month 16. Some animals lost up to 50kg at this period. After this period the animals showed a fast growth until slaughter at month 26. The points labelled as FR180 and FR200 shows animals that would have made it if the minimum weight was 180kg or 200kg. The animals labelled as FRF are those that have failed due to weight limit by month 26, note that they still have 10 months to grow before they reach month 36 which means they could still make it into the 200kg range. 

Figure 2: Growth of individual animals from wean to slaughter

Figure 3: Average growth of the whole herd

The figure above shows the average growth of the whole heard. It is important to note the animals grew to this level and were slaughtered when they still had 10 months to grow. The animals were slaughtered in autumn as farmers were not willing to take them over winter again. 

In conclusion, farmers need to have a dry season feed supplementing plan or your animals will lose up to 50kg. The other issues to note is that with some bit of feeding the animals can reach the target weight within two years. This is highly possible if the farm is stocked correctly. If a farmer can feed 1% concentrates as from wean the animals may be fully grown by 18 months. Feeding them younger may results in faster growth than when finished in the last months before slaughter. It might also be economical to feed them earlier. Don’t forget that the best beef is in an animal younger than 3 years, so try to get it out of your farm before this age. The last message is that most abattoirs in South Africa punishes farmers for delivering an animal with a carcass weighing less than 200kg, in some cases for up to R6 less per kg. If interested in supplying FR beef join the HighVBP project by communicating with Dr Baldwin Nengovhela of DALRRD.

Dr NB Nengovhela; H Burrow; SP Ndala; MA Ntobeng, S Malangwane & MN Selepe 
Scientific Manager: Animal Production DALRRD NkhanedzeniN@dalrrd.gov.za

Disclaimer: The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of Mzansi Agriculture Talk.

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