Finishing of slaughter lambs on natural pastures

Claudia Mack, Animal nutritionist - The major sources of nutrition in sheep are natural pastures. This differentiates the sheep industry from dairy and meat cattle industry, which to a large extent and often completely makes use of harvested feeds, like for example hays, silages and concentrates to provide the necessary nutrients for the livestock. Essentially, sheep production can be improved by improving pastures and or by supplementing deficiencies and as supplemental feed during droughts.When finishing lambs on the veld, the aim should be to attain maximum profit and not necessarily maximum gain, where the profitability of rounding off depends mainly on the ratio between the meat and feed price. In order to attain the maximal genetic growth potential of the lamb, both the ecological and nutritional effects should be at an optimum. There would be no sense in spending a large amount of money on the best quality feed, if environmental factors are not optimal. The best feeding programme will be different from one operation to the next and should be decided upon when all factors having an impact on the profit margin have been reviewed. There are however, a few rules of thumb to follow when finishing lambs on natural pasture. Young lambs derive most of their nutritional requirements from the milk supplied by the ewe in the first few weeks of life. The more milk the ewe produces; the later the lamb has to start obtaining its nutrition from pastures, reducing/postponing its risk for ingesting internal parasites from the pastures. Thus creep feeding indirectly has a positive effect on lamb growth. After 4 to 6 weeks the lamb can derive more than 50% of its nutritional requirements from sources other than milk. If lambs are given access to creep feed, they may be weaned early and transition onto a high concentrate diet for finishing will be easier. Creep feeding firstly increases the intake of energy, protein, minerals and vitamins and secondly results in a lower pasture intake which in turn lowers the ingestion of internal parasites. If lambs have exclusively had access to pasture only, the feeding programme should be worked out in such a way that concentrates are gradually introduced.Creep feedWhen creep feed is supplied a product with low or no urea should be considered, as the nitrogen supplied by urea at this early stage in the life of the lamb would not be utilized and energy is needed in order to excrete the urea. Further, such a creep feed should be very palatable, containing up to 10% molasses, high quality lucerne and maize (amongst other grains), preferably ground or rolled for lambs younger than two months old. A product such as Feedmaster Ram, Lamb and Ewe pellets or Feedmaster Creep Feed can be considered. The Creep feed area should be placed in such a way that lambs will have easy access to it and it should ideally have entrance openings on both sides. Feeding space per lamb should be between 5-6cm. Feeders should be designed in such a way that that lambs cannot stand or play in them. 1.8m2 of floor space should be allowed per lamb housed in the pen. Feeding younger lambs will result in a more favourable feed conversion ratio which will have a favourable effect on profitability. These lambs would typically have received creep feed in the suckling period and later have been adapted to a high energy diet, like for example Feedmasters’ Sheep Finisher Pellets. It has to be kept in mind that it takes about two weeks for the lamb to adapt to a diet. After this time the rumen bacterial population will have developed and the finishing of lambs can be started. Start with feeding lambs 300g/day of a finisher diet together with ad lib roughage, for one week. Thereafter increase the feed amount to 500g/lamb per day. At the onset of the third week lambs can be fed ad lib with the finisher feed. When finishing lambs for slaughter on high energy diets it is important to be aware of certain potential metabolic problems. Urinary calculi may cause problems in ram and ewe lambs. However, feeding diets with urinary acidifiers such as Ammonium Chloride as well as a calcium to phosphorus ratio of 2:1 can help prevent the occurrence of urinary calculi. Rumen acidosis may be experienced when lambs are fed a high energy diet without access to adequate roughage. Using a diet with a rumen buffers can greatly reduce the incidence of rumen acidosis. Changes in the ration fed, as well as well as the amount fed should be avoided, as sudden changes in the diet, both in composition as well as quantity, can lead to increased incidences of rumen acidosis. Before lambs are placed on a finishing diet, vaccinations against pulpy kidney must be given. Finishing lambs on pasture may take longer than when high energy diets are fed in confinement but the economic profit may be greater. Pasture is the cheapest source of feed available to farmers and maximum use of this should be made. Furthermore, the consumer demand is shifting towards more naturally produced mutton and this may be a niche market worth exploring. However, when lambs are finished on pastures, supplementation should be provided, especially in times when the nutritional quality of the pasture is low, in order to ensure adequate growth and acceptable carcass composition. Lambs finished on pasture can be expected to gain 250g per lamb per day. The marketing weight and age of sheep varies between breeds due to different genetic makeup. Lambs should not become too heavy before marketing as more fat will be deposited leading to a lower feed conversion ratio with a concomitant increase in feeding cost and a decrease in profitability. Lambs are usually sent for slaughter at a live weight of between 35kg and 45kg. The dressing percentage achieved will depend on carcass composition and will have a marked influence on the profitability of the entire enterprise. On a carcass with the desired composition the dressing percentage will typically be in the order of 47%.

Finishing of slaughter lambs on natural pastures

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Republikein 2025-06-16

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Finishing of slaughter lambs on natural pastures

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