Sheep Feeding

Credit:Biovision-Infonet

Traditional sheep husbandry systems are ecologically well-balanced, but often the food available to sheep is fibrous and deficient in energy and protein and minerals are in short supply. Nutrition plays a major role in the overall productivity, health, and well-being of the sheep flock. Because feed costs account for approximately two-thirds of the total cost of production, it is important that producers consider nutrition management a top priority. The sheep owner should try to balance the demands of the sheep breed and the quality (and quantity) ot the feed. It makes no sense to breed a very energy rich ration demanding sheep breed when it is impossible to meet that in the management. Nutrient requirements of sheep vary with differences in age, body weight, and stage of production. The five major categories of nutrients required by sheep are:

1) Water;
2) Energy; 
3) Protein; 
4) Vitamins; and 
5) Minerals.  

During the grazing season, sheep are able to meet their nutrient requirements from pasture and a salt and mineral supplement. Pastures of mixed grass and clover, alfalfa and small grain serve as excellent sources of nutrition for growing lambs. A source of clean, fresh water should be provided to sheep at all times.Ewe body weight does not remain constant throughout the year, but changes with stage of production. Nutrient requirements are lowest for ewes during maintenance, increase gradually from early to late gestation, and are highest during lactation. Decisions affecting feeding management are improved significantly by knowing ewe body weight and condition score at three distinct stages of production:  

1) Three weeks before breeding; 
2) Mid-gestation; and 
3) Weaning.  

Condition score to measure body fat

Condition score is a subjective measure of body fat that is most easily determined by handling ewes down their back. It is the best method available to monitor nutritional status and overall well-being of the sheep flock. Condition scores range from 0 to 5, with 0 being extremely thin and 5 being very fat. Condition scores at either end of the scale are undesirable. Ideally, ewes should range from a condition score of 2.5 at weaning to a 3.5 at lambing. When necessary, thin ewes are separated and fed additional energy to increase body condition. Conversely, obese ewes are separated and fed a lower energy diet at a stage of production when body weight loss is acceptable. It should be noted that problems with over fat ewes are far fewer than those associated with ewes that are too thin. 

Body condition score 0 – extremely thin

Backbone: The bones form a Sharp narrow ridge. Each vertebra can be easily felt as a bone under the skin. There is only a very small eye muscle. The sheep is emaciated and you have a serious animal welfare problem

Short Ribs: The ends of the short ribs are very obvious. It is easy to feel the squarish shape of the ends. Using fingers spread 1 cm apart, it feels like the fingernail under the skin with practically no covering

Body condition score 5 – very fat

Backbone: The spine may only be felt (if at all) by pressing down firmly between the fat covered eye muscles. A bustle of fat may appear over the tail. This sheep is seriously overweight and the diet needs to be modified.

Short Ribs: It is virtually impossible to feel under the ends as the triangle formed by the long ribs and hip bone is   filled with meat and fat. The short rib ends cannot be felt.

Starting two weeks before breeding and continuing two weeks into the breeding period, ewes should be placed on high-quality pasture or supplemented daily with 0.5 to 1 Kg whole shelled maize or barley. This management practice is called flushing and has been shown to improve lambing percentage by 10 to 20 percent. Flushing works best with mature ewes that are in moderate body condition, and has been shown to be more effective for early- and out-of-season breeding than at the seasonal peak of ovulation. Most prenatal deaths occur within the first 25 days after breeding and are usually associated with poor nutrition. Therefore, it is important not to make dramatic reductions in nutrient supplies during the breeding season. Pastures with more than 50 percent legumes should be avoided during breeding because legumes may contain compounds that reduce conception rates.From breeding to six weeks before lambing, the ewe flock can be maintained on permanent pastures, small grain pastures, stockpiled fescue, aftermath crop fields, or hay. Fetal growth is minimal, and the total feed requirement of the ewe is not significantly different from a maintenance diet. (See table 1) The developing fetus reach approximately two-thirds of its weight during the last six weeks of pregnancy. Rumen capacity may be limited with ewes carrying multiple fetuses. Therefore, it is important to supplement ewes with 0.5 to 1 kg of maize/energy rich feed, in addition to their normal diet starting six weeks before lambing, to prevent pregnancy toxemia, low birth weights, weak lambs at birth, and low milk production. Producers should be careful not to over feed grain during late gestation, which could result in lambing difficulty caused by large lambs.  

Table 1. Daily requirements of ewes with body weight of 50 and 70 kg in different stages of production for energy and protein, calcium and phosphorus and for vitamin A and E and the maximum dry matter intake capacity (DMI) of the ewes.

Live-weight	Category	DailyGain (g)	DMI	MEM/cal	CrudeProtein(g)	Calciumg	Phosphorusg	Vit AIU	Vit EIU
50	Maintenance	10	1.0	2	95	2.0	1.8	2350	15
	Flushing breeding	100	1.6	3.4	150	5.3	2.3.6	2350	24
	Gestation:15 weeks	30	1.2	2.4	112	2.9	2.1	2350	18
	Last 4 weeks gestation 140% lambing/last 4-6 weeks suckling singles	18045	1.6	3.4	175	5.9	4.8	4250	24
	Last 4 weeks gestation 200% lambing	225	1.7	4.0	196	6.2	3.4	4250	26
	First 6-8 weeks suclingsingles/Last 4-6 weeks suckling twins	-2590	2.1	4.9	304	8.9	6.1	4250	32
70	Maintenance		1.2	2.4	113	2.5	2.4	3290	18
	Flushing breeding	100	1.8	3.8	164	5.7	3.2	3290	27
	Gestation: 15 weeks	30	1.4	2.8	130	3.8	3.3	3290	21
	Last 4 weeks gestation 140% lambing/last 4-6 weeks suckling singles	18045	1.8	3.8	193	6.2	5.6	5950	27
	Last 4 weeks gestation 200% lambing	225	1.9	4.4	214	7.6	4.5	5950	28
	First 6-8 weeks suckling singles/Last 4-6 weeks suckling twins	-2590	2.5	5.9	334	9.3	7	5950	38

After lambing, the energy and protein requirements of the ewe increase by 30 and 55 percent, respectively. Failure to supplement ewes accordingly results in excessive body weight loss, low milk production and poor lamb gains. Protein supplementation is especially critical for ewe flocks with a high percentage of multiple births. Unless high quality legume hays are fed, protein supplementation will be necessary as a part of the grain portion of the diet. A general rule of thumb for concentrate feeding of lactating ewes is 0.5 Kg of grain for each ewe nursing the lamb. Ewes should be sorted into feeding groups based on type of rearing (single, twin, etc.) to make sure grain supplements are neither over- or underfed. 

Urea

Urea is not normally used in organic herds, and if used, very careful measuring needs to take place as urea used badly can kill your animals very fast. Do not try urea unless there are goof facilities for weighing and mixing feeds properly.
Urea is not a protein supplement, but a source of non-protein nitrogen (NPN) for protein synthesis by rumen bacteria. It should be used only in conjunction with high-energy feeds such as maize. Urea, which is 45 percent nitrogen and has a crude protein equivalent of 281 percent, should not supply over one-third of the total nitrogen in a diet. To determine the grams of nitrogen in a diet, multiply the total kilos of crude protein in the diet by 16 percent. Other general rules for the use of urea are:

 1) Should not be more than 1 percent of the diet or 3 percent of the concentrate mix; and

 2) Should not be more than 5 percent of a supplement to be used with low grade roughages.

Minerals

Salt and mineral supplementation is required on a free choice, year-round basis. Failure to supplement salt and minerals results in low fertility, weak lambs at birth, lowered milk production, impaired immunity, and numerous metabolic disorders. A variety of salt and mineral supplements specifically formulated for sheep are commercially available. These supplements range from trace mineralized salt (TMS) fortified with selenium to complete mineral mixes containing all of the macro and micro minerals required by sheep. 

Vitamins

Pasture or high-quality hay provides the vitamins required by most categories of sheep. However, after a drought, or when low-quality hay or silage is fed, a supplement supplying vitamins A, D, and E may be needed. 

Table 2, Average daily mineral and trace element requirements for different categories of sheep

Category	kg DM	Ca	P	Mg	Na	K	Cl	S	Cu	Co	Mo	J	Zn	Mn	Fe	Se
		g	g	g	g	g	g	g	mg	mg	mg	mg	mg	mg	mg	mg
Gestation	1.9	5.6	3.7	1.7	0.7	4.9	1.1	2.85	14	0.2	0.19	1.5	30	38	92	0.18
2 kg milk	2.3	8.3	7	3.8	1.9	11	3.8	3.3	15	0.26	0.23	1.5	56	46	19	0.32
3 kg milk	2.6	10	9.2	4.4	2.4	13	4.8	3.9	18	0.3	0.26	1.5	66	52	23	0.37

Weaning lambs

• The ability to supply adequate grass for lambs is the key to successful weaning. Lambs are selective grazers, selecting the sweetest and best grass for themselves. Do not allow ewes to compete with lambs for grass from 14 weeks onwards.
• Ensure lambs are in a well fenced field with an abundance of leafy grass. Sward (grass) heights should be maintained at 8-9cm. Move lambs to the best grass on the farm, ideally after-grass containing clover.
• Do not graze tightly. Use a follower group of stock to clean up.
• During rains and up to weaning lambs may gain 300g per day. After weaning they can only gain 100-200gm per day, depending on grass quality and availability.
• Consider using a pour-on for fly strike as they have a shorter withdrawal period than dips. Do not dip if you expect to sell within the next month; Clip around the tail to keep clean. (antibiotic withdraw time double in organic)
• A stomach worm dose for lambs at weaning is advisable, especially when moving to after-grass. It is not necessary if a drench was used in the last few weeks.
• Treat for cobalt in deficient areas. Lambs suffering from cobalt deficiency (pining) will lose condition and wool will dry out. The main method of supplementation is orally – it can be mixed with drinking water, as cobalt by injection is not as effective. Dosing every 2 weeks with cobalt sulphate is recommended in deficiency situations.
• Restrict ewe feed for 1-2 weeks to stop milk production when weaning lambs early. This can be on a bare paddock or indoors. Do not restrict too severely, as this could leave ewes too low in condition before going to the ram. Be careful if keeping ewes indoors for a few days after weaning to ensure that they are well bedded, otherwise an outbreak of mastitis is possible.
• Select potential replacement ewe lambs post-weaning, in cold season when only the poor performing ewe lambs are left it is too late.
• Where grass becomes scarce, introduce meal and continue meal feeding until lambs is sold. Concentrate supplementation of weaned lambs on pasture increases carcass weight and leads to earlier drafting of lambs. Response to meal feeding post-weaning is 10-12 kg/kg carcass wt. With meal at PS130/tonne and lambs at Ksh.350/kg this means that Ksh.200 spent on meal will give a return of Ksh.350.

Table 3. Daily requirements of lams with adult body weight of 50 and 70 kg for energy and protein, calcium and phosphorus and for vitamin A and E and the maximum dry matter intake capacity (DMI) of the ewes.

Live-weight	Category	DailyGain (g)	DMI	MEM/cal	CrudeProtein(g)	Calciumg	Phosphorusg	Vit AIU	Vit EIU
30	Replacement ewe lambs	225	1.2	2.8	185	6.4	2.6	1410	18
40		180	2.0	3.3	176	5.9	2.6	1880	21
40	Replacement ram lambs	330	1.8	4.1	243	7.8	3.7	1880	24
60		320	2.4	5.5	263	8.4	4.2	2820	26
30	Finishing lambs, 4-7 month	300	1.3	3.4	191	6.6	3.2	1410	20
40		275	1.6	4.4	185	6.6	3.3	1880	24
50		200	1.6	4.4	160	5.6	3.0	2350	24