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Information sheets   |   Elsenburg infopaks   |   Animals, management: 17

Rounding off of lambs in feeding pens Afrikaans | Xhosa

Click to enlarge!		 When mutton and lamb are scarce, meat prices usually go up. It then becomes profitable to round off lambs in a feeding pen, if the price of feed is not too high. It is also sometimes necessary to round off animals in a feeding pen when grazing is scarce and lambs cannot reach a desired slaughter mass on grazing alone. In addition, when a producer is weaning a lot of multiple lambs, it is also sometimes necessary to round off some of the lambs in a feeding pen.

The rounding off of lambs under intensive conditions, however, requires high management input for it to be profitable. The success of the rounding off of lambs also depends on management factors like housing, feeding and disease prevention.

The profitability of rounding off depends mainly on the ratio between the price of meat and the price of feed (the meat:feed price ratio). When animals are bought for rounding off, the purchase price of the animals also plays a decisive role.

The change in profit on top of the cost of feed when there is a change in the price of feed and/or meat, with estimates for slaughter mass, dressing percentage, mortality, mass increase, feed conversion and the purchase price and/or starting value of lambs, is given in Annexure A.

Sheep can be fed successfully in pens or sheds.

Desired age and weaning mass

Lambs weaned early can go into a feeding pen when they are eight weeks old. The younger the lambs, the better the feed conversion that can be expected in the feeding pen. The longer lambs are kept on grazing, however, the lower the total cost of rounding off. It is preferable for lambs not to be lighter than 15 kg. Feed conversion in lambs drops as the lambs become older and heavier, because more fat than meat is deposited on the carcass.

The ideal marketing age of lambs depends on the breed. For example, SA meat merino lambs are usually marketed at about 40 kg. Dorper lambs are marketed slightly earlier (at about 38 kg) because the carcasses become too fat at a higher mass. Animals should not be too heavy when they are marketed because feed conversion would have slowed down, which means that the carcasses would have become too fat, which, in turn, means lower grading.


Click to enlarge!		 HOUSING

Floor type

The floor should be such that urine does not collect and create wet, dirty conditions. If possible, feeding pens should be built on a slope to prevent such conditions.

Feeding troughs

When sheep are fed ad lib, at least 4 to 10 cm of feeding space per sheep should be available. Troughs should be such that wastage is limited. They should also be protected from rain.

Click to enlarge!		 Watering troughs

Watering troughs should be positioned as far as possible from feeding troughs. They should not leak, otherwise they create a breeding ground for parasites. Wet conditions can also cause foot-rot.

Pen size

Groups of only 30 to 50 sheep per pen should be allowed. Dominant, average and shy feeders should be separated into groups where possible.

Click to enlarge!		 Floor space

About 1.8 m2 per sheep should be available in open pens. About 0.4 m2 per sheep is sufficient for slatted floors.

Click to enlarge!		 Shade

About 0.4 m2 of shade per sheep should be available.

FEEDING LAMBS IN A FEEDING PEN

Acclimatisation

Animals should be acclimatised when they are put in a feeding pen. During the first week, enough hay plus 300g of concentrate per sheep per day should be provided. During the second week, hay plus 500g of concentrate per sheep per day should be provided. After that, concentrate can be provided on an ad lib basis. Diets should be changed as little as possible, otherwise acclimatisation problems can result. It should be borne in mind that animals take about two weeks before they are acclimatised to a specific diet. Roughage should always be available to limit digestive problems.

Feeding requirements

For maximum effectiveness, a diet for young lambs should meet the following requirements:

  • total digestible nutritive material: 68%
  • total coarse protein: 16%
  • roughage: 12 - 16%
  • calcium: 0.8%
  • phosphate: 0.3%

It is important that the diet is balanced. Although a balanced diet can sometimes be more expensive, it is usually more effective.


Click to enlarge!		 Physical form

The milling or processing of grain is of limited value to sheep. It is even preferable for grain to be kept whole, since this combats acidosis. Pelleting has a noticeable benefit on intake and performance but, if rounding off is not practised, the large capital expenditure needed to acquire the necessary implements may not be justified.

Roughage can be milled (through a 12 to 18 mm sieve) or chopped, since this lessens wastage and benefits production. It is essential for a binding agent to be added to milled rations to prevent dustiness.

Enriched grains

Great success is being achieved with enriched or chocolate grain. The processing cost is slight and enriched grain is well buffered and therefore safe for animals. The following are general guidelines for the provision of enriched grain:

  1. About 10 to 20% roughage should be given - separately - at the same time as the grain. This improves utilisation, especially in low-fibre grain like mealies.
  2. Mixtures should not be mixed longer than 14 days before they are used, since the binding agent could dry out.

Type of grain

Mealies have traditionally been used as a source of grain in the diets of sheep. Certain types of small grain, however, can also be used with great success. Although the energy content of small grain is lower than that of mealies, the protein content is higher. Barley, wheat and triticale generally seem to be able to be used without problem in the diet of lambs. Oats has a low-energy content and is not suitable as the only source of grain. Rye is relatively tasteless and contains certain anti-nutritional factors. It could also be contaminated with ergot, which would limit its value as a component in the diet of lambs.

Quality of roughage

The quality of roughage plays an important role in the intake of dry material and the growth rate of lambs in a feeding pen. When high-quality roughage is replaced by low-quality roughage, there is usually a drop in intake and the rate of growth of lambs.

High-quality protein

It is essential for high-quality protein (a low-degradable source) to be included in the diet when young lambs are being fed. Good results are attained when about 4% fish-meal is included. The inclusion of oilcake meal (from soya beans or cotton seed, for example) also gives good results.

Creep feed 

When lambs are put in a feeding pen, it is good practice to provide creep feed during the pre-weaning period to limit acclimatisation problems.

Additives and growth stimulants

Various additives and growth stimulants are available to improve production. These include: 

  • additives that increase intake (like antioxidants, flavourants and binding agents), 
  • substances that chemically change digestion and absorption (like buffers, enzymes and antibiotics), 
  • substances that affect the metabolism of an animal (like implants with a hormonal effect and sedatives), 
  • substances that improve the health of an animal (like fungus inhibitors, antibiotics, eenopblaas-middels, coccidiostates, parasiticides and vermicides) 
  • and substances that influence rumen functions and modify the end products of rumen digestion (like ionophores). 
  • Tauratec, Salocin, Ralgro and Tilosien are the growth stimulants and antibiotics that are generally used locally.

FEEDING PEN PROBLEMS

Acidosis ("suurpens")

Acidosis is probably the most common problem of ruminants in a feeding pen. The condition arises when animals take in too much starch-rich feed and the rumen pH drops quickly. It can, in addition to sudden mortalities, also cause problems like diarrhoea and laminitis (sore feet). Giving animals enough time to acclimatise and including a buffer (like feed lime, slaked lime, bentonite or caustic soda) in the diet can prevent acidosis. Providing enough roughage can also prevent it.


Click to enlarge!		 Pulpy kidney

Sheep tend to get pulpy kidney when their feed is changed. Animals should therefore be inoculated when they are put in a feeding pen.

Stones in the bladder

Stones in the bladder often occur in wether and ram lambs in a feeding pen. As a preventative measure, 0,5 to 1,0% sal ammoniac or another relevant substance should be mixed into rations. Stones in the bladder are related to a too-high intake of phosphate and a Ca:P ratio of less than 2:1,

Internal parasites

It is advisable for animals to be dosed with a broad-spectrum substance when they are put in a feeding pen to clear them of parasites.

Click to enlarge!		 Liver abscesses

When animals take in too little roughage, it can lead to irritation of the rumen wall and liver abscesses can develop later. The inclusion of Tilosien or a similar substance in the diet can also help to prevent the condition.

Lung infections

If feeding pens are such that urine cannot run off, ammonia builds up, which causes lung problems. Good ventilation is therefore critical in rounding off facilities.

Poisoning

When ionophores and/or growth stimulants are included in rations, care must be taken that the right quantities are used and that they are mixed into the rations thoroughly. These substances can be deadly if the recommended doses are not adhered to. Ureum is also poisonous and should be included in a diet at a maximum of 2% only. Special care must be taken that fodder with ureum in it does not get wet in the rain, since ureum can dissolve in standing water and lead to the intake of toxic levels by sheep.

Copper poisoning

Care must be taken that a diet does not contain more than 10 ppm of copper, since high intake levels of copper are toxic to sheep.

Vitamin B1 (thiamine) shortage

Animals that are fed grain for long periods sometimes develop a thiamine shortage. This condition can be prevented if 5 to 10g of thiamine hydrochloride per tonne of fodder is mixed into the fodder. If shortages do occur, sheep can be dosed with 1g of thiamine hydrochloride per sheep per day.

Annexure A

FEED PRICE MEAT PRICE
12.00  13.00 14.00 15.00 16.00 17.00 18.00
0.40 107.68 125.32 142.96 160.60 178.24  195.88

213.52
0.45 102.68 120.32 137.96 155.60 173.24 190.88 208.52
0.50 97.68 115.32 132.96 150.60 168.24 185.88 203.52
0.55 92.68 110.32 127.96 145.60 163.24 180.88 198.52
0.60 87.68 105.32 122.96 140.60 158.24 175.88 193.52
0.65 82.68 100.32 117.96 135.60 153.24 170.88 188.52
0.70 77.68 95.32 112.96 130.60 148.24 165.88 183.52
0.75 72.68 90.32 107.96 125.60 143.24 160.88 178.52
0.80 67.68 85.32 102.96 120.60 138.24 155.88 173.52
0.90 57.68 75.32 92.96 110.60 128.24 145.88 163.52
1.00 47.68 65.32 82.96 100.60 118.24 135.88 153.52 
1.10 37.68 55.32 72.96 90.60 108.24 125.88 143.52
1.20 27.68 45.32 62.96 80.60 98.24 115.88 133.52
1.30 17.68 35.32 52.96 70.60 88.24 105.88 123.52
1.40 7.68 25.32 42.96 60.60 78.24 95.88 113.52
1.50 -2.32 15.32 32.96 50.60 68.24 85.88 103.52

Table 1: The effect of a change in feed and meat price on profit on top of the feed and purchase cost of lambs

  • Estimated income (selling price)
    slaughter mass × dressing percentage × meat price × percentage marketed

 

  • Direct expenditure (cost of feed)
    mass increase × feed conversion efficiency × price of feed

 

  • Starting value
    starting mass × purchase price

 

  • Profit on top of cost of feed
    estimated income - direct expenditure - starting value

Example

Starting mass : 20 kg
End mass : 40 kg
Mass increase : 20 kg
Dressing percentage : 45% (0.45)
Meat price : R8.00 / kg
Feed conversion efficiency : 5.00 kg feed needed per kg mass increase
Mortality : 2% (0,02)
Percentage marketed : 98% (0,98)
Price of feed : 50c/kg (R500/ton)
Starting value : R3.20 / kg lewende massa
     
Estimated income : 40 x 0.45 x 8.00 x 0.98
(Selling price) = R141.12
     
Direct expenditure : 20 x 5.0 x 0.50
(Cost of feed) = R50.00
     
Starting value : 20 x 3.20
(Purchase price) = R64.00
     
Profit on top of cost of feed : R141.12 - R50.00 - R64.00
(Per lamb) = R27.12

Other factors that should be taken into account:

  • transport cost (where applicable )

  • capital expenditure for facilities

  • maintenance and labour

  • medicine

Table 1 gives the change in profit on top of the cost of feed when there is a change in the price of feed and/or meat, with above estimates for slaughter mass, dressing percentage, mortality, mass increase, feed conversion and the purchase price and/or starting value of lambs.

TS Brand & B Aucamp
ELSENBURG / Research