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2nd March 2021 Admin

Nutrition for Sheep 8: Popular Husbandry Systems

Contents

  1. The objectives of the sheep enterprise
  2. The concepts of sheep nutrition
  3. Feed intake
  4. Energy
  5. Protein
  6. Minerals & Vitamins
  7. Water
  8. Popular husbandry systems

Popular Husbandry Systems

UK sheep systems have evolved from an ancient ancestry which may be referenced back to roman times. Modern sheep farming has been developed into a sophisticated meat production agronomy which is able to produce a big surplus of lamb for export.

Currently we can summarise UK sheep farming as follows: –

• Mountain sheep farming. This is based on rearing small but very hardy breeds of sheep that are able to thrive on poor mountain pastures. The mountain sheep breeds usually only produce one lamb each season. This is quite desirable since it would be hard for the mother to find enough food from the hill pastures to produce enough milk to rear more than one strong healthy lamb.

These breeds of sheep mature at low carcass weights and in themselves they are not particularly useful to the UK consumer who generally demand a larger carcass.

There has been a developing market for lightweight lamb for export. Brexit may well affect this and the future is by no means assured.

The purebreds include, Scottish Black Face, Swaledale, Cheviot, Welsh Mountain and Dartmoor sheep.

These small breeds are either kept pure or they are crossed with upland sheep breeds to produce crossbred or mule ewes. These may then in turn be crossbred to the bigger lowland breeds to produce commercial lamb.

All ram (tup) lambs are humanely castrated at birth and enter the meat markets except some pure pedigree rams that are retained for breeding.

• Upland (Hill) sheep breeds are slightly bigger than the mountain sheep and as such they add size and prolificacy to the mountain breeds. They usually produce twin lambs and provided they are fed well around lambing time they manage this feat with relative ease.

Upland sheep breeds include Border Leicester, Blue Faced Leicester, Dorset Horn, and Dorset Down sheep.

The upland breeds produce stock rams which are used to cross with mountain sheep and may also be crossed with lowland sheep breeds. The mountain sheep cross provides mule ewes for breeding with lowland sheep to provide meat lambs. The lowland cross is less common but is also for meat lambs.

• The Lowland breeds are the larger of the sheep breeds. They are generally bred pure and kept to produce stock rams for crossing with commercial mules.

There is a big demand for good stock rams from these breeds and they can attract very high prices in the autumn ram sales.

Lowland breeds include Suffolk, Texel, Charolais, Blue-de-Maine, and Beltex breeds.

• Commercial mule flocks form the main sheep population in the UK. They tend to be managed quite well and aim to produce a good crop of twin lambs each year.

The pedigree and commercial sheep systems are quite different. Pure bred sheep are selected on the basis of a high-quality carcass. The breeding programs are becoming very progressive.

Pedigree tup and ram diets are probably the most finely tuned rations fed to any of the ruminants. This is not a market for the amateur.

Mineral tolerances are very fine indeed. Sheep do not require more than 12 mg / Kg of copper. An excess of this element will easily kill some of the lowland breeds.

Mountain sheep tend to be more copper tolerant, but they too can suffer from toxicity. On the other hand, a deficiency of copper can cause equally extreme problems with newborn lambs in particular.

The best advice when sourcing feed is to buy specialised premixed feeds or use the services of a good nutritionist.

Fat lamb production falls into two categories.

• Extensive grass-fed lamb. This system is the most popular. The ewes are tupped (served) in the autumn and the lambs are born in the spring, just as the grass starts to grow at its highest nutritional value. The ewes have the benefit of high value grass and are able to consume enough to produce the amount of milk that the young twin lambs require to achieve target growth rates. The ewes and lambs stay together until the lambs are weaned. This usually coincides with the first draw, when the lambs are separated from the ewes and are either deemed ready for market or are put onto appropriate diets to either store or finish.

The ewes are then given around 6 to 8 weeks before they are ready for tupping again.

• Intensive early lamb. This system sees the lambs being born inside and reared on concentrates so that they achieve rapid weight gain. The main motivation for this system is to have the lambs ready for the traditional spring lamb market. Normally there was a dearth of lamb to be found at this time of year since most spring born lambs would be finished by February at the latest. The market price of lamb therefore peaked around Easter. The response to this was to lamb early and cash in on the high prices in April May and June. This system is not as attractive as it one was since lamb supply is better, and refrigeration has spread availability.

Farmers get paid for lamb on the basis of Conformation (shape), Fat cover and Weight. These criteria have fueled the breeding and feeding programs. The optimum lamb is not too fat and has a big value in its back legs and chops. Feeding can have a big effect on fat cover, but breeding is the key influence on conformation.

Wool has very little value since the collapse of the eastern bloc markets. Sheep once valued for wool are not so prized as they once were. The Herdwick fleece was famed for its coarse texture and suitability for carpet manufacture. Wool is still collected but its value hardly pays for the cost of shearing.

Sheep health is an area of prime importance. They are susceptible to many diseases so routine vaccination and dipping is part of normal stock husbandry. During the year of the sheep there are few opportunities to handle the ewes, it is important to keep a check on the condition of the ewe in order to ensure that she is capable of coping with her next crop of lambs. Teeth, Feet, and condition should be looked at each time there is an opportunity, and management adjusted accordingly.

Spring lambs

Sheep Nutrient Requirements: Assumes Zero Weight Change

Pregnant ewes Days from Conception
Assumes Zero Weight Change Single Lamb Twin Lamb
Ewe Weight Nutrient 98 112 126 140 98 112 126 140
Kg                  
55 DMI (Kg) 1.2 1.2 1.2 1.1 1.3 1.3 1.3 1.2
  ME (Kg) 7.9 8.8 9.9 11.3 8.9 10.2 12 14.4*
  MP (Kg) 72 76 82 89 77 84 93 104
  Calcium (g) 3.1 3.8 4.5 5.1 3.9 5 6.2 7.2
  Phosphorus (g) 2.7 2.9 3 3 3.2 3.5 3.8 3.8
  Magnesium (g) 1 1 1.3 1.3 1 1 1.5 1.5
  Sodium (g) 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8
  Vit A (i.u.) 5500 5500 5500 5500 5500 5500 5500 5500
  Vit D (i.u.) 550 550 550 550 550 550 550 550
  Vit E (i.u.) 40 40 40 40 45 45 45 45
75 DMI (Kg) 1.5 1.5 1.5 1.4 1.6 1.6 1.6 1.5
  ME (Mj) 10.1 11.1 12.5 14.3 11.3 12.9 15.2 18.2*
  MP (g) 86 91 98 106 92 100 111 126
  Calcium (g) 3.8 4.6 5.6 6.3 4.7 6 7.6 8.9
  Phosphorus (g) 3.4 3.6 3.8 3.8 4 4.4 4.7 4.8
  Magnesium (g) 1.3 1.3 1.7 1.7 1.3 1.3 2 2
  Sodium (g) 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5
  Vit A (i.u.) 7500 7500 7500 7500 7500 7500 7500 7500
  Vit D (i.u.) 750 750 750 750 750 750 750 750
  Vit E (i.u.) 55 55 55 55 60 60 60 60

Notes:

  1. Dry matter intake (DMI) drops just before lambing due to reduced rumen capacity.
  2. ME* intakes are just about impossible to achieve just before lambing due to increased requirement and reduced intakes.
    This is the common cause of pregnancy toxaemia (Twin Lamb Disease).
  3. Calcium requirements just before lambing are nearly double the normal levels of intake.
  4. Supplementary feeding is the only way to achieve nutrient requirements of modern upland and crossbred sheep prior to lambing.

Sheep Nutrient Requirements: Losing Weight

Pregnant ewes Days from Conception
Losing Weight Single Lamb Twin Lamb
Ewe Weight Nutrient 98 112 126 140 98 112 126 140
Kg                  
55 DMI (Kg) 1.2 1.2 1.2 1.1 1.3 1.3 1.3 1.2
  ME (Kg) 6.0 6.8 7.9 9.3 6.9 8.2 10.0 12.3
  MP (Kg) 66 70 76 83 71 78 87 98
  Calcium (g) 3.1 3.8 4.5 5.1 3.9 5 6.2 7.2
  Phosphorus (g) 2.7 2.9 3 3 3.2 3.5 3.8 3.8
  Magnesium (g) 1 1 1.3 1.3 1 1 1.5 1.5
  Sodium (g) 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8
  Vit A (i.u.) 5500 5500 5500 5500 5500 5500 5500 5500
  Vit D (i.u.) 550 550 550 550 550 550 550 550
  Vit E (i.u.) 40 40 40 40 45 45 45 45
75 DMI (Kg) 1.5 1.5 1.5 1.4 1.6 1.6 1.6 1.5
  ME (Mj) 7.1 8.1 9.4 11.2 8.2 9.9 12.2 15.1*
  MP (g) 77 82 89 98 83 91 102 117
  Calcium (g) 3.8 4.6 5.6 6.3 4.7 6 7.6 8.9
  Phosphorus (g) 3.4 3.6 3.8 3.8 4 4.4 4.7 4.8
  Magnesium (g) 1.3 1.3 1.7 1.7 1.3 1.3 2 2
  Sodium (g) 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5
  Vit A (i.u.) 7500 7500 7500 7500 7500 7500 7500 7500
  Vit D (i.u.) 750 750 750 750 750 750 750 750
  Vit E (i.u.) 55 55 55 55 60 60 60 60

Notes:

  1. 1. Dry matter intake (DMI) drops just before lambing due to reduced rumen capacity.
  2. ME* intakes are achieved at the expense of body condition loss approaching lambing.
    Rapid condition loss and inadequate intakes give rise to pregnancy toxaemia (Twin Lamb Disease).
  3. Calcium requirements just before lambing are nearly double the normal levels of intake.
  4. Supplementary feeding is the only way to achieve nutrient requirements of modern upland and crossbred sheep prior to lambing.

Sheep Nutrient Requirements: Lactating Ewes

Lactating ewes Weeks of Lactation
Q62.5 Single Lamb Twin Lamb
Assumes 55 Kg ewes are losing 50g liveweight per day and 75 Kg ewes are losing 75g liveweight per day.
Lactation Week 1 – 4 5 – 8 9 -12 1 – 4 5 – 8 9 – 12
Nutrient
Ewe Weight Kg DMI (Kg) 1.5 1.7 1.6 1.6 1.8 1.7
55 ME (Kg) 14.9 14.0 11.5 20.2* 18.1 14.2
MP (Kg) 148 139 114 198 179 140
Calcium (g) 6.1 5.9 4.8 8.4 7.8 6.0
Phosphorus (g) 5.4 5.5 4.6 7.2 6.9 5.6
Magnesium (g) 2.2 2.1 1.7 2.9 2.6 2.1
Sodium (g) 2.1 2.0 1.9 2.4 2.3 2.0
Vit A (i.u.) 5500 5500 5500 5500 5500 5500
Vit D (i.u.) 550 550 550 550 550 550
Vit E (i.u.) 40 40 40 45 45 45
75 DMI (Kg) 1.9 2.2 2.0 2.0 2.3 2.1
ME (Mj) 21.1 19.6 15.0 28.1* 23.5 17.7
MP (g) 214 200 155 280 237 182
Calcium (g) 9.0 8.8 6.7 12.0 10.5 7.9
Phosphorus (g) 8.0 8.1 6.4 10.2 9.4 7.4
Magnesium (g) 3.3 3.1 2.5 4.2 3.6 2.9
Sodium (g) 3.0 2.9 2.6 3.4 3.1 2.8
Vit A (i.u.) 7500 7500 7500 7500 7500 7500
Vit D (i.u.) 750 750 750 750 750 750
Vit E (i.u.) 55 55 60 60 60 60

Notes:

  1. * These energy levels are unachievable, so high levels of concentrate supplementation are essential.
  2. Supplementary feeding is the only way to achieve nutrient requirements of modern upland and crossbred sheep supporting twins and triplets.
  3. As Genetic potential increases so does food conversion efficiency, but it is also true that higher output animals should also be fed on a higher plain of nutrition.
  4. Pedigree lowland breeds are generally much heavier sheep but due to their superior abilities for growth, they require more concentrated diets, from birth through to maturity.
Sheep Nutrient Requirements
Feeding standards for growing lambs     Lambs of 20Kg liveweight
Category Nutrient Liveweight Gain
0 grams / day		 Liveweight Gain
50 grams / day		 Liveweight Gain
100 grams / day		 Liveweight Gain
150 grams / day		 D M I
grams / day
Female ME (MJ) 3.4/3.2 4.5/4.2 5.8/5.3 -/6.5* 460-560
MP (g) 32** 45 58 71
Castrate ME (MJ) 3.4/3.2 4.5/4.2 5.7/5.2 -/6.2* 460-560
MP (g) 32** 47 61 76
Male ME (MJ) 3.9/3.7 4.8/4.5 5.8/5.4 -/6.4* 460-560
MP (g) 32** 47 61 76
All sexes Ca 0.7 1.6 2.5 3.4
P 0.5 1.0 2.0 3.0
Mg 0.38 0.50 0.61 0.72
Na 0.57 0.63 0.69 0.75
Vitamin A (iu) 660 660 660 660
Vitamin D (iu) 120 120 120 120
Vitamin E (iu) 21 21 21 21

Notes:

  1. Indicates that First figures are for Q 55 (Low “D” value) diets.
  2. Second figures are for Q 65 (Medium “D” value) diets.
  3. 20 Kg Lambs growing at 150 grams per day are unlikely to achieve this on less than Q 65.
  4. ** Includes allowance for wool growth. (11 grams of MP per day)