FEEDING PROGRAMME FOR SHEEP UNDER EXTENSIVE AND SEMI-INTENSIVE CONDITIONS

The aim of this article is to provide broad guidelines for a feeding programme for sheep under extensive and semi-intensive conditions. If you need more specific information, please contact Dr. Jasper Coetzee.

 

1. Flush feeding of breeding rams

Producers are often willing to pay considerable amounts for breeding rams, but are sometimes not prepared to make a little extra effort or spend a few extra rand on properly preparing these animals to ensure maximum reproduction rate. To ensure a high conception rate and a high twinning rate, rams must be in an excellent condition (3.5 to 4.0 CS); fertile and mating dexterity; possess a very high libido (sex drive) and be top fit to serve ewes multiple times during their oestrus cycle. The rams must also have large testes (scrotum circumference greater than 35 cm at 15 months of age) for adequate sperm production. As sperm cells take approximately two months to develop, supplementary feeding must be given for at least two months. From two months prior to the mating season breeding rams must therefore be fed a bypass protein-based ram flush ration such as Voermol Superlamb pellets or a ram flush mix (200 kgVoermol SS 200 + 150 kg Voermol Procon + 80 kg Voermol Molasses meal +
575 kg milled maize or whole barley) at a limited level (500 – 1 500 g/ram/day). There must be sufficient feeding space (± 60 cm/ram) so that all rams can eat simultaneously. If pasture is scarce, good quality lucerne hay must be supplemented ad lib. separately. Alternatively a complete ram ration [250 kg milled lucerne (25 mm) + 425 kg milled maize or whole barley + 200 kg Voermol SS 200 + 50 kg Voermol Procon + 80 kg Voermol Molasses meal] can be fed.

As soon as supplementary feeding commence, begin exercising the rams (30 minutes’ of fast walking, twice daily). Where exercised (fit) rams were mated with ewes, the conception rate of the ewes was 92 % as opposed to the 76 % of the ewes mated with unexercised rams. All other activities, such as the necessary dosing (for both roundworm and nasal worm) and vaccinations (e.g. multi-clostridial vaccine), must be administered approximately six weeks prior to the mating season. Moreover, Multimin™ (G1853) as well as Vitamins A and E must be injected three months prior to the mating season. Vaccinations that cause fever, as for blue tongue, for example, must be injected after the mating season. Adequate cool and clean drinking water must be available at all times and be as close to shade as possible. Provide shade in warm months and shelter against inclement weather conditions. The semen quality of breeding rams can be improved by dosing them from eight weeks prior to the mating season with wheat germ oil (± 25 ml/ram) two to three times a week.

 

2. Growing out of replacement ewes

To ensure a high lambing percentage, ewe lambs may not lose any mass from weaning until lambing for the first time. Moreover, they must weigh 80 % of adult body mass at first mating if they are mated for the first time at 12 months or younger. If they are mated at older than 12 months, the target mass is 90 % of adult body mass. The optimal growing out of replacement ewes (maiden ewes) is essential for unlocking their full genetic production and reproduction potential. Where Dohne Merino young ewes reached 80 % of an adult ewe’s mass at mating at 11 or 14 months of age, 55 % of these young ewes were pregnant with twins. Replacement ewes must therefore always be given supplementary feeding from their own weaning up to weaning their first lambs, after which they can be incorporated into the adult ewes’ feeding programme.

Depending on the quality and quantity of the pasture, the replacement ewes must be given the following concentrate mix on both dry pasture (500 to 1 000 g/ewe/day) and green pasture (100 to 500 g/ewe/day): 200 kg Voermol SS 200 + 50 kg Voermol Procon + 40 kg Voermol Molasses meal + 700 kg milled maize or whole barley. By weighing the repalcement ewes or a marker group regularly every two to three weeks, the feeding level of the supplement can be regulated in such a way that the calculated growth rate is maintained for reaching the target mass at first mating. Feed this concentrate supplement daily with adequate feeding space for each animal to ensure the optimal growing out of replacement ewes. Weaned ewe lambs that are grown out on unharvested maize "weimielies" or maize cop residues with plenty of spilled maize, must be supplemented with Voermol Landelek (150 – 200 g/ewe/day); an even better mix is 150 kg Voermol Landelek plus 50 kg Voermol Procon (250 – 350 g/ewe/day). On unharvested soya beans or on soya crop residues with plenty of spilled soya beans Voermol Molovite (200 g/ewe/day) is recommended. For every 1 kg that a ewe is heavier at first mating, her lambing percentage increases by approximately 1.5 to 2.5 %. To ensure a high lambing percentage, replacement ewes must be in an excellent condition (3.5 CS) at first mating and have reached their target mass at first mating. Moreover, the highest lambing percentage is obtained if the feeding level of replacement ewes is increased already from two months prior to the mating season by placing them in reserved camps and continuing with the concentrate supplement till 21 days before the mating season when switching to flush feeding.

 

3. Flush feeding of breeding ewes

Ewes whose mass increases at mating are more inclined to produce twins than those that maintain or lose mass. Conception and twin births drop if the ewes lose mass shortly before the mating season. Ovulation rate (number of ova secreted per oestrus cycle) determines the upper limit of the ewe’s fecundity (multiple births) and is genetically controlled. The extent to which a ewe reaches her genetic reproduction potential depends on environmental factors such as nutrition and management (Downing & Scaramuzzi, 1991). According to Rowe and Atkins (2005), nutrition has the greatest effect (> 70 %). Therefore, to ensure a high lambing percentage, ewes must be in an excellent condition (3.5 CS) at mating and for every kg that they are heavier at mating, the lambing percentage increases with approximately 1.5 to 2.5 %. For ewes to progressively gain weight, they must be placed in reserved camps two months before the mating season and, from at least three weeks prior to the mating season, fed a flush lick for at least six weeks.

On dry pasture Voermol Maxiwol pellets are given as a flush lick at 300 to 400 g/ewe/day. Maxiwol Production pellets must not be fed where the drinking water is brackish or where plenty of brackish shrubs occur, as it will cause an inadequate lick intake. No salt lick or rock salt must be given either. On green pasture or where the drinking water is brackish or where there are a lot of brackish shrubs, a Maxiwol lick mix (250 kg Voermol Maxiwol concentrate + 200 kg milled maize or whole barley + 50 kg salt) must be given at 300 to 400 g/ewe/day as a flush lick. Where teasers are used, the feeding level of the flush lick for adult ewes can be reduced to 250 g/ewe/day by the fourth week of the mating season and to 200 g/ewe/day the week after. The latter is at maintenance feeding level and should be sufficient for early pregnant adult ewes until the rams are removed, should there be adequate pasture available. If teasers are not used, the flush feeding level must be reduced from the sixth week of the mating season; the reason being that research shows that the highest embryo survival occurs where ewes are fed a maintenance feeding level shortly after conception. On the other hand, the flush lick for replacement ewes is provided at the same level (300 g/ewe/day) as for flush feeding to maintain their recommended target growth rate (± 70 to 180 g/ewe/day) until the rams are removed. Any loss of mass must be prevented among both the replacement and adult ewes during the mating season, as it may cause embryo resorption. The latest research shows that it is economically justifiable and non-negotiable to provide flush feeding to ewes that had twins in their last lambing season, as well as to replacement ewes that are mated for the first time. The rest of the ewes are given flush feeding only if they are lean or thin (< 3.0 CS), but not if they are in an excellent condition (3.5 CS) as it is then not economically justifiable.

Four to six weeks prior to the mating season, ewes must be injected with Multimin™ (G1853) plus Vitamins A & E, as well as given the necessary dosing and vaccinations (multi-clostridial vaccine & enzootic abortion). From four weeks prior to the mating season ewes must be kept calm and no stressful activities must be carried out during this time. Where ewes were shorn and dipped two to four weeks prior to the mating season, the conception was 89 % as a result of these stressful activities compared to 96 % where these activities were performed more than four weeks prior to the mating season. Where ewes were driven over a long distance before mating, the resultant stress reduced their ovulation rate by up to 60 %. Avoid mating ewes on clover and lucerne pastures that suffer from moisture stress, are damaged by insects or infected by viruses or fungi as these plants, under these conditions, produce hormones that may have a negative impact on the lambing percentage.

 

4. Nutrition during early pregnancy

Any factors that cause stress must be avoided during early (first month of) pregnancy as it may cause embryo mortalities. Where ewes are handled during mating by bringing them to the kraal every four days to identify ewes which conceived, their lambing percentage was only 65 % compared to the 98 % of the ewes that were not handled. To prevent embryo mortalities and foetal deaths, where possible no stressful activities (e.g. dosing, vaccinating, shearing, dipping, etc.) should be performed during the mating season to at least one month after the rams have been removed. The difference (also known as the disappearance factor) between the number of lambs scanned and those actually born (dead or alive) is an indication of the embryonic and foetal losses (foetuses that die) and it can easily be as high as 23 % and even higher.

During the first month of pregnancy adult ewes must maintain their mass while replacement ewes must gain approximately 70 to 180 g/ewe/day in mass (NRC, 2007). Owing to the risk of resorption, ewes may not be weighed during early pregnancy. The use of teasers is highly recommended as it makes flush feeding even more profitable. Where ewes were given flush feeding (300 g/ewe/day) for six weeks from three weeks prior to the mating season, adult ewes’ feeding level can be adjusted after six weeks of flush feeding if teasers were used. Where teasers are used, the feeding level of the flush lick for adult ewes can thus be reduced to 250 g/ewe/day by the fourth week of the mating season and the next week to 200 g/ewe/day. The latter is maintenance feeding level and if adequate pasture is available, it should be sufficient for early pregnant adult ewes until the rams are removed. If teasers are not used, the flush feeding level must be reduced only from the sixth week of the mating season. The reason for reducing the flush feeding level is that research shows that the highest embryo survival occurs where ewes are fed at a maintenance feeding level shortly after conception. On the other hand, the flush lick for replacement ewes is provided at the same level (300 g/ewe/day) as for flush feeding, until the rams are removed, to maintain their recommended target growth rate.

Any loss of mass in both replacement and adult ewes must be prevented during early pregnancy as it may result in embryo resorption. When the rams are removed, the supplementary feeding level of both replacement and adult ewes is adjusted, usually by switching to other licks. The licks must ensure that a moderate increase in mass is maintained during mid-pregnancy (refer to Mid-pregnancy, Section 5). Keep ewes calm and stop all activities during the mating season and the first few weeks (± 4 – 6 weeks) after ram removal to limit embryonic and foetal deaths (Henderson, 1990). Provide shade (trees or shade-cloth) if the day temperature is higher than 28 °C, but definitely if it is above 32 °C. Ewes must always have free access to clean, good quality drinking water that is as close to the shade as possible. Very brackish and salt water raises heat stress that increases the risk of embryonic and foetal losses.

 

5. Nutrition during mid-pregnancy

During mid-pregnancy (months two and three of pregnancy) the optimal growth of the placenta (afterbirth) is crucial. A small afterbirth causes an increase in lamb deaths owing to lambs being are too small (less than 3.5 kg) at birth resulting in poor viability of the newly born lambs, poor maternal (mothering) properties and low milk production by the ewes (Kelly & Ralph, 1990). The placenta produces hormones that are essential for the maintenance of pregnancy, development of the udder and the stimulation of maternal properties. A decrease of up to 25 % in milk production has been observed in ewes that are underfed before Day 100 of pregnancy in spite of being supplied with ad lib. nutrition during the last six weeks of pregnancy (Mavrogenis, et al., 1980).

During the second and third months of pregnancy adult ewes with single foetuses must increase in mass by ± 50 g/day; those with twin foetuses by ± 80 g/day; and those with triplet foetuses by ± 100 g/day. In the case of replacement ewes, the respective increases in mass are approximately 100; 110 and 140 g/day (NRC, 2007). Feeding levels for the respective groups of ewes can only be adjusted after scanning, which takes place approximately 42 days after the rams have been removed.

It often happens that, owing to very good feeding conditions, the producer has little control over the pasture intake of mid-pregnant ewes, sometimes resulting in ewes becoming very or even excessively fat. This can largely be prevented by increasing the carrying capacity. At scanning, ewes must be divided into groups (dry ewes; ewes with single foetuses; ewes with twin foetuses and ewes with triplet foetuses) so that differential feeding (feeding according to need) can be applied. However, pregnant replacement ewes must be kept and managed separately from pregnant adult ewes. To facilitate management, and with due discretion, some of the respective groups can be combined. With differential feeding, precision feeding can be applied. It is the most cost effective and economical way of feeding ewes. All dry ewes, including replacement ewes mated for the first time, must be culled at scanning. Alternatively, dry ewes can be moved to a cross-breeding flock, but at their first failure (not weaning a lamb) they must be summarily culled.

If mid-pregnant ewes are unable to maintain their target mass increase on the available pasture, switch to a suitable maintenance lick at the time of ram removal. The type of lick depends on the type of pasture, as well as on its quality and quantity. On abundant dry pasture one of the following maintenance licks (100 to 180 g/ewe/day) can be supplied:

 

  1. Rumevite Econolek (V11147).

  2. 250 kg Voermol Winslek concentrate (V17865) + 50 kg milled maize, whole barley or Voermol Molasses meal (V1995) + 100 kg salt.

  3. Voermol Protein block (V10448).

 

If the dry pasture is scarce or if the recommended maintenance licks do not maintain the prescribed increases in mass, particularly in the case of replacement ewes, one of the following production licks (250 to 350 g/ewe/day) can be supplied:

 

  1. 700 kg Rumevite Econolek + 300 kg milled maize or whole barley.

  2. 400 kg Voermol Winslek concentrate + 400 kg milled maize or whole barley +
    150 kg salt.

  3. Voermol Energy block (V11456) or Voermol Production lick (V10108) or Voermol Maxiwol Production pellets (V15415).

 

On green cultivated pasture Voermol Molovite (V7266) at 200 g/ewe/day, and on green natural veld pasture Voermol Supermol (V7267) at 250 g/ewe/day, can be supplemented to maintain the prescribed increases in mass. If the prescribed increases in mass cannot be maintained on these licks on green pasture, they must be mixed 50:50 with milled maize or whole barley and fed at respectively 400 and 500 g/ewe/day.

 

6. Nutrition during late pregnancy

Late pregnancy (fourth and fifth months of pregnancy) is one of the most important stages in the reproduction cycle of ewes because approximately 80 % of the foetal growth occurs during this stage of pregnancy; this causes a significant increase in the feeding needs of late pregnant ewes (Bell, 1995; Dawson, et al., 1999). The fact that approximately 80 % of lamb deaths are related to the ewes’ nutrition during the last few weeks before and immediately after lambing, further emphasises the significance of adequate and correct nutrition during late pregnancy (Seymour, 1998). If ewes are underfed for even one week during late pregnancy, good nutrition afterwards can never fully compensate for it (Mellor & Matheson, 1979). Late pregnant ewes with single foetuses must therefore take in adequate nutrition (i.e. bypass protein, energy, minerals, trace elements and vitamins) from four weeks; those with twin foetuses from six weeks; and those with triplet foetuses from eight weeks before lambing to stimulate udder-development; increase colostrum and milk production; improve the ewes’ maternal properties and vitality of lambs; to limit birth problems (yellowish lambs at birth) and abnormally thick and sticky colostrum; and to ensure an ideal birth mass (3.5 to 5.5 kg) that promotes maximum lamb survival. All these contribute to limiting lamb deaths and/or improving lamb growth. According to Robinson (1990), udder development is directly dependent on the intake of the quantity of bypass protein. The supplement of bypass protein on poor quality dry pasture increased the mass of lamb weaned per ewe mated by up to
5.1 kg, as well as the subsequent lambing percentage by up to 28 percentage units (Brand, 1999). Adult ewes must increase at least 15 % (i.e. 7.5 kg for a 50 kg ewe) and replacement ewes 10% in mass during the last two months of pregnancy to ensure a desired birth mass
(3.5 – 5.5 kg) for high lamb survival.

Providing a high bypass protein lick (300 – 500 g/ewe/day) such as a Maxiwol lick mix
(250 kg Voermol Maxiwol + 200 kg milled maize or whole barley + 50 kg salt); Maxiwol Production pellets; Maxiwol Readymix or Maxi block prior to lambing is non-negotiable. If the pasture is scarce or where ewes are allowed to lamb in lambing camps or lambing pens, a complete ration [375 kg milled lucerne (20 – 25 mm lengths) + 350 kg milled maize or whole barley + 150 kg Voermol Maxiwol concentrate + 50 kg Voermol Procon + 80 kg Voermol Molasses meal] must be fed from four or even six weeks before lambing. As this ration contains urea, the maximum intake must be limited to 2.5 kg/ewe/day to prevent urea poisoning. If higher levels must be fed, contact dr. Jasper Coetzee for an alternative ration. Ewes must be adjusted slowly and gradually to this complete ration to prevent acidosis. The peak and sustainability of the milk production of ewes that are underfed during late pregnancy are lower than those of well-fed ewes. Ewes must also be injected with Multimin™ (G1853) as well as Vitamins A and E four to six weeks before lambing and be given the necessary dosing and vaccinations (multi-clostridial).

 

7. Nutrition during lactation

The feeding level during the first two months post lambing must be such that ewes do not lose more than 10 % of their mass. Studies show that where the ewes lose more mass, their subsequent lambing percentage was lower by up to 25, and in one case, 51 percentage units. Ewes may lose condition in early lactation, as long as the condition score drops to no lower than 2.0, preferably not lower than 2.5. The aim for replacement ewes, lambing for the first time, must be to lose no more than 3 % and for adult ewes to lose no more than 7 % in mass during the first two months of lactation.

A limitation in feed intake can lower milk production by up to 50 %. The growth of twin lambs is detrimentally affected if lactating ewes experience a limitation in nutrition for longer than 10 days. The milk production of lactating ewes is detrimentally affected by a nutrition limitation of four weeks; no increase in milk production takes place even if ad lib.feeding is provided after this period. Ideally ewes should be moved to green cultivated pasture or unharvested maize (weimielies) after lambing. To ensure a high weaning mass and a high lambing percentage in the subsequent lambing season, the same bypass protein-based lick or complete ration that was fed during late pregnancy should also be fed during early lactation on the available pasture. After lambing, the respective late pregnancy feeding levels of the Maxiwol licks must be increased to ± 100 g/ewe/day while complete feeds for ewes that reared single and twin lambs respectively are fed at approximately 3 % and 4 % of body mass. Lactating ewes on "weimielies" or maize crop residues with plenty of spilled maize must be fed a special lick mix (150 kg Voermol Landelek + 50 kg Voermol Procon) at 250 to 350 g/ewe/day. On unharvested soya beans or on soya crop residues with plenty of spilled beans Voermol Molovite (200 g/ewe/day) is recommended.

If ewes are not scanned, the wet-and-dry technique must be applied to identify dry ewes and ewes that have lambed but are not rearing lambs at tail-docking. All these ewes, including replacement ewes mated for the first time, must be culled. These ewes must be sold and the income can be used to purchase pregnant ewes, preferably ewes pregnant with twins. Alternatively dry ewes can be moved to a cross-breeding flock, but at their first failure (no lamb weaned) they must be summarily culled.

 

8. Creep feeding of suckling lambs

Because of the extremely effective feed conversion of young lambs, everything possible must be done to make sure that they grow to their maximum genetic growth potential. The two main factors that limit the growth of suckling lambs at pasture is the inability of the lambs’ rumen to utilise pasture effectively and the lambs’ relatively small rumen size when they graze a pasture with high moisture content (Joyce & Rattray, 1970). The provision of creep feeding to suckling lambs is non-negotiable for profitable sheep production. Creep feeding prevents weaning shock and makes it possible to wean lambs as early as 72 days of age at a minimum mass of 25 kg. Where lambs are weaned at 100 days, creep feeding will ensure that their weaning mass is at least 45 %, but preferably 50 % of their adult mass. Lambs getting creep feeding may be 10 to 20 % heavier at weaning and marketed up to 50 days earlier while a large percentage of lambs may be marketed directly from the ewes at three to four months of age. Suckling lambs market directly from the ewes have a very high dressing percentage (> 50 %). A ewe lamb whose mother was given good nutrition from four weeks prior to lambing up to weaning and the ewe lamb itself up to 14 weeks of age, but preferably up to puberty, will ensure maximum development of the future reproduction potential of the ewe lamb. Muscle cell increase in lambs occurs up to three months of age and muscle growth up to approximately nine months of age. Maximising both increases the carcass value of slaughter lambs and the eventual adult size of young rams and ewes. In the case of the latter it results in improved lifetime production and reproduction.

A milled creep feed mix (150 kg Voermol SS 200 + 175 kg Voermol Procon + 40 kg Voermol Molasses meal + 625 kg milled maize or whole barley) or creep pellets (150 kg Voermol SS 200 + 150 kg Voermol Procon + 600 kg milled maize or whole barley + 100 kg lucerne) may be fed ad lib. from two weeks of age to approximately two weeks post weaning. Lambs receiving creep feeding and ear-marked for slaughtering may be implanted with a suitable ear implant (e.g. Ralgro® or Zeraplix) at six weeks of age as it improves growth and feed conversion.

 

9. Feeding dry ewes

After weaning, dry ewes must be given adequate opportunity to regain the mass that they had lost since the previous mating season. To save flush feeding, ewes at the stage where their lambs are weaned must be divided into at least two groups according to condition (lean vs. good condition). The lean ewes must then be put to better pasture to regain their condition so that, at the onset of the flush feeding period, they are in good condition (at least 3.0 CS). Depending on the condition of the ewes at weaning, it appears that the best results in lambing percentage are obtained if lambs are weaned at least three months prior to the next mating season. Studies in this regard show that it benefits the conception of ewes (98 % vs. 90 % and 94 % vs. 79 %). An effort should be made to have dry ewes in good condition (at least 3.0 CS) at the start of the flush period. If the quality and quantity of the available pasture are such that this target (i.e. 3.0 CS) is not attainable, a lick must be provided. The type of lick depends on the type of pasture and its quality and quantity. One of the following production licks (250 to 350 g/ewe/day) may be considered:

 

  1. 700 kg Rumevite Econolek + 300 kg milled maize or whole barley.

  2. 400 kg Voermol Winslek concentrate + 400 kg milled maize or whole barley +
    150 kg salt.

  3. Voermol Energy block (V11456) or Voermol Production lick (V10108) or Voermol Maxiwol Production pellets (V15415).

 

On green cultivated pasture Voermol Molovite (V7266) at 200 g/ewe/day and on green natural veld pasture Voermol Supermol (V7267) at 250 g/ewe/day can be supplemented to maintain the prescribed increases in mass. If the prescribed increases in mass cannot be maintained on these licks on green pasture, it they be mixed 50:50 with milled maize or whole barley and fed at 400 and 500 g/ewe/day respectively.

 

10. Finishing of weaned lambs on cultivated pasture

By using a special bypass protein lick and following specific management guidelines, weaned lambs destined for the slaughter market can be finished considerably more profitably on cultivated pasture than in a feedlot. Despite the lambs in this system being able to maintain the same growth rate as in a feedlot, they can be finished up to 30 days and in some cases up to 60 days earlier than those that were given no supplementary feed on the pasture. This results in more animals being finished on pasture or that more pasture is available for the rest of the flock. Prerequisites for successful finishing are well grown (28 – 32 kg) and healthy lambs implanted with Ralgro® or Zeraplix, as well as the provision of Voermol Superlamb pellets on a lush, dense stand, abundant, actively growing, good quality, green, leafy and palatable cultivated pasture. Voermol Superlamb pellets must be fed daily in troughs at 300 to 800 g/lamb/day. Adequate feeding space must be available so that all the lambs can eat simultaneously. The lambs must be given the necessary dosing and vaccinations (multi-clostridial) before finishing commence.

 

11. Finishing of weaned lambs in a feedlot

Diversification is generally accepted as a strategy for limiting risk in agriculture. In this regard feedlot finishing of own lambs must be an integral part of sheep farming to lower the risk. To realise maximum profit in a feedlot, it is crucial to decrease feeding costs per kg mass increase mainly by improving the feed conversion ratio (kg feed intake/kg mass increase). Feed conversion ratio (FCR) improves as the energy-concentration of the ration is increased due to the fact that the feed intake decreases while the growth rate (ADG) increases. However, maximum profit cannot be generated by making the feedlot ration cheaper by using cheaper raw materials (e.g. low-quality roughage, by- and/or waste products) with a low energy density and nutritive value because this will lead to a drastic decrease in feed conversion. On the other hand, the more expensive high quality raw materials become the more important and critical the use of growth promoters such as feed additives and growth stimulants become to improve the feed conversion and thus maximise profit.

A high inclusion of bypass protein sources (e.g. 10 to 15 % Voermol Procon) in feedlot rations can be highly recommended as they improve FCR and promote muscle growth, which in turn raises the dressing percentage (Beerman, et al., 1986). As the bypass protein intake increases, the FCR and the dressing percentage improve. The better the quality of the roughage, the higher its digestibility and the more palatable it is – ensuring a higher energy intake and a better FCR. As the quality of the lambs that are finished also has a significant impact on the feed conversion efficiency and growth rate, and thus the profitability of feedlot finishing, only lambs with an excellent genetic feed conversion potential should be finished. Prerequisites for generating maximum profit in a feedlot are: well grown (28 – 32 kg) and healthy lambs that preferably received creep feeding; successful adaptation; effective processing and excellent feedlot management and facilities. Moreover, the provision (three times a day) of a high quality, correct balanced, highly palatable, energy-rich ration with the necessary buffers, ammonium salts, growth promoters, bypass protein, a series of mineral and vitamins to feedlot lambs is equally crucial. An example of such a feedlot ration is: 125 kg milled lucerne hay (25 mm) + 200 kg Voermol SS 200 + 100 kg Voermol Procon + 40 kg Voermol Molasses meal + 550 kg milled maize or whole barley. Additional activities that must be performed are implanting Ralgro® or Zeraplix; administering the necessary dosing and vaccinations (multi-clostridial); injections of Multimin, Vitamins A and E and separating lambs into homogeneous groups.

 

12. Finishing of weaned lambs on crop residues or unharvested maize (weimielies)

The intake of large quantities of grains reduces the digestibility and intake of dry crop residues (e.g. maize leaves and grain stubble) and can also cause bladder stones, acidosis, poor animal performance and even deaths due to acidosis. Moreover, grains are deficient in protein, particularly bypass protein, as well as calcium, magnesium, zinc and copper that limit animal performance. "Weimielies" as well as small grain and maize crop residues with plenty of spilled grain are particularly suitable for the finishing of weaned lambs, but are also a valuable nutritional source for lactating ewes and replacement animals. To limit deaths due to acidosis and simultaneously promote animal performance cost-effectively, Voermol Landelek must be supplemented to sheep (150 – 200 g/head/day) on "weimielies" or crop residues with plenty of spilled grain. Animals must first be gradually adapted on grains and Landelek for approximately 14 days before moving them to "weimielies" or crop residues, with plenty of spilled grain (refer to the Voermol Product Manual for proper adaptation procedures). Where lambs are finished on unharvested soya beans or on soya crop residues with plenty of spilled beans, supplementation of Voermol Molovite (200 g/lamb/day) is recommended. Animals destined for the slaughter market must be implanted with Ralgro® or Zeraplix at the start of finishing.

 

13. Rearing breeding rams

Breeding rams must be reared under conditions similar to those under which their offspring must produce and reproduce. Most commercial sheep producers prefer hardy and well-adapted rams and consequently young rams must be reared on the veld with no or minimal supplementary feed. If the veld cannot maintain growth of at least 90 g/day from weaning to performance testing at 12 or 15 months of age, a low level (300 – 750 g/ram/day) of the ram flush mix (200 kg Voermol SS 200 + 150 kg Voermol Procon + 80 kg Voermol Molasses meal + 575 kg milled maize or whole barley) must be provided daily as a supplement with adequate feeding space for all the rams to eat simultaneously. If the feeding space is limited or if rams cannot be fed daily, 100 kg of the grains in the mix can be replaced with 100 kg salt. After performance testing, the rams can be finished for sales on the veld with the ram flush mix (500 – 1 500 g/ram/day) or with a complete ram ration (200 kg Voermol SS 200 + 50 kg Voermol Procon + 80 kg Voermol Molasses meal + 425 kg milled maize or whole barley + 250 kg milled lucerne).

The selection of breeding rams must be very accurate as they can contribute up to 75 % of the genetic improvement of the flock. The selection of breeding rams must be based on economic important breed characteristics as well as their BLUP breeding values. The BLUP breeding values provide the most accurate indication of a ram’s predicted breeding value. If BLUP breeding values are unknown, breeding rams must be selected on breed characteristics, but then the focus should be on increasing the flock’s reproduction rate. Preference must be given to rams born from mothers who weaned more lambs than they had lambing opportunities; multiple born rams and rams with firm, elastic testes with a scrotum circumference of more than 35 cm at 15 months (i.e. for rams in good condition) as well as for rams with a very high libido. Rams with a high libido usually are alert; have a lively and vital attitude; clear and bright eyes; an aggressive nature and the colour of the inside of the thighs (groins) should be purple.

 

14. Conclusion

Effective supplementary feeding practices form an integral part of effective management and breeding practices. These practices must not be seen in isolation, but as a unit – together they form the basis of a profitable sheep enterprise. The strategic supplementation of the correct nutrients (particularly bypass protein and energy; minerals; trace elements and vitamins) in the right quantity and combinations to grazing animals is crucial in ensuring a maximum and cost-effective response. Simultaneously, a very high level of management must be maintained while continuously adapting management practices. In this regard it is absolutely essential to meticulously follow an effective and scientifically based management, disease prevention and health control programme that are continuously adjusted as new information and technology become available. To ensure a highly productive sheep flock, genetically superior breeding animals (ideally using only proven, superior breeding rams, genetically better than the flock) must be selected while unproductive animals (e.g. those that do not lamb or do not wean a lamb) must be summarily and constantly culled.

To generate maximum profit, producers must set the right priorities and focus on those aspects (e.g. reproduction rate) that generate the most profit. To earn a high price and a price premium for their marketable product, producers are obliged to produce a quality product and one demanded by consumers; they can no longer produce any quantity of any quality as they like. Producers are strongly urged to visit highly successful producers (e.g. winners of the Sheep Farmer of the Year competitions) and learn from them about being successful. Such producers always have new ideas and find new ways of doing things. Producers are further urged to use the latest technology, because, according to prof. Johan Willemse (2001), producers will find it difficult to increase income over costs without using new technology and management methods. In this regard, Australian consultants agree that the willingness of producers to apply new technology and management practices in their flocks largely determines their profitability. Producers are requested to consult the best experts in this regard to become familiar with the latest technology and the most profitable production system(s) for their specific circumstances.

Article by Voermol