Basic Sheep nutrition and marketing of lambs - Lecture 171
1. Describe the consequences of poor nutrition on ewes and growing lambs.
Basic nutrition:- most time spent grazing
- pasture, crops, hay, silage, concentrate feeds
- most have EV of 8-13 MJME/kg DM
Lamb nutrition:
- 1st 6 weeks life - lamb growth rate is milk from ewe
- 6-12 wks still consume milk but also solid food
- 10-12 wks - weaned
Feeding lambs for slaughter:
- grow 100-409 g/day
- slower growing takes longer to reach slaughter
- eat considerably more food per kg carcass
- growth rates vary according to:
- breed, gender, quality/quantity of nutrition, disease
- lambs unable to grow at reasonable rates are often sold as 'store' lamb
- many upland/hill farms sell some/all lambs as store lambs
- many farmers only achieving 100-200 g/day
Poor lamb nutrition:
- reduced growth rate
- poor slaughter weights
- poor carcass confirmation
- long-time to slaughter = decrease profit margin
- spend longer time on farm
- consume more feed
- health care costs increased
- more chances of death
- compete with ewes for feed
- underfed ewes lambs tend to have reduced ovulation rates as adults
- slow lamb growth is often due to disease as well as poor nutrition
Feeding ewes:
- focus on lamb production
- getting ewe in lamb, large litter size
- birth of healthy normal lambs
- rearing lambs to weaning
- good lamb weaning weight
- Aim for consistent BCS throughout the year
- ewes - voluntarily eat ~3% body weight per day
Consequences of poor nutrition for Ewes:
- Flushing (increase nutrient intake pre-mating)
Pre-mating
- poor pre-mating BCS (target 3.0)
- extreme - reduced pregnancy rates
- reduced ovulation
- No-flushing effect
- less lambs
- extreme under-nutrition: embryonic/foetal reabsorption
- poor placental development
- small lamb birthweight, reduced viability
- increased lamb mortality
Late pregnancy
- metabolic disease (ewe death)
- reduced colostrum production
- reduced colostrum quality
- increase in lamb mortality
Lactation:
- reduced milk production - under feeding of lambs
- loss of body condition, which needs to be regained before mating
- smaller lambs, less ££
2. Discuss marketing of finished lambs, and carcass classification.
Slaughter Lambs:
- prices determined by carcass quality and size
- quality - confirmation and fat cover
- ideal - lots of muscles, medium fat
- Carcass size based on 'dead weight'
- once pelt, viscera and feet removed (~44-48%)
- most UK lambs are 16-22 kg carcass weight
- Confirmation - shape of carcass; amount of muscle/fat relative to skeleton
- Fatness: fat cover over lumbar region and rump
- scored on 1 (low) - 5 (high) scale
- 3 and 4 are subdivided into L (leaner) and H (fatter)
Finished lambs:
- returns depend on market and carcass (dead weight)
- Different markets like different things:
- UK: 16-22 kg
- EU: 16-19 kg
- Spain/Italy: 8-12 kg
- Most lambs kill out at 44-48% - therefore liveweight 36-36kg
Store lambs:
- not ready for slaughter
- slow-growing on farm of origin
- buyer - needs to grow rapidly to make a profit
- source: hill, upland farms
Carcass confirmation:
- E - U carcass - down rams x mule cross
- O - P carcass - hill ewes
- Class R is most common
- England:
- ~60% E/U/R 2/3L
- ~20% Poor confirmation
- ~20% Too fat
- Carcass quality of slaughter lamb is determined by its parental breed types
Lowland economics:
Half-bred ewes X Down rams
Maternal traits:
- high lambing %
- good mothering/high milk yield
- longevity
Carcass improvement of hill sheep:
- genetic variation for
- liveweight
- loin muscle
- fat depths and conformation
- essential that improvement in carcass quality does not compromise
- hardiness of ewe
- survival of lamb
Constraints to genetic improvement of longwool (upland) breeds:
- Multi-trait selection index - to balance maternal and carcass traits
- Lack of genetic information
- Lack of performance recording
- Average flock size = 11
- sire referencing schemes
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