Presentation on theme: "Sheep - 1. In this unit you will learn about... Breeds of Sheep and their characteristics. Dental Formula. Target weights. Gestation Period and Oestrous."— Presentation transcript:
In this unit you will learn about... Breeds of Sheep and their characteristics. Dental Formula. Target weights. Gestation Period and Oestrous cycle (duration & length). Ram & Ewe Selection. Mixed Grazing. Creep Feeding. Breeding Management Programme- Flushing & Sponging Management of the pregnant ewe. Management of lamb from birth to slaughter. Sheep Dipping and shearing. Sheep Housing. Wool.
Lamb weighs 3 –5 kg at birth 30-40kg at slaughter Gestation period 149 days (5 Months) Oestrous cycle 17 days Duration of oestrous 36 hours Ruminant Phylum Chordata Even Toe Ungulates
Growth rates increase by 10-15% Tillering- a denser sward & increased DM production Flush of grass around dung is ate by sheep. This is unpalatable to cattle. Even recycling of nutrients
1. State the length and duration of the oestrous cycle. 2. What is length of gestation? 3. Name the phylum that sheep belong to. 4. State the dental formula foe a sheep. 5. What is mixed farming? 6. Give the advantages of mixed grazing.
Mountain & Lowland Breeds. Wool/Lamb/Ewe Production Degree of prolificy – 1,2,3 Growth rate & Conformation Blackface Mountain Wicklow Cheviot Galway Suffolk Down The Belclare Improver
Cross between Galway & Finnish Landrace –to improve prolificy X & Llynn –to improve conformation
1. Name 3 categories of breeds. 2. Name 4 breeds. 3. Give their characteristics.
If flock is inadequate or poor quality –Replace either ewes or RAMS- Cheaper to replace 1 RAM = 50 Ewes naturally 1 RAM = 8/10 ewes Synchronisation
Good Carcass Good Conformation Good prolificy. Wool/ewes/meat Feed: fertility is increased with high quality feed
EWE Good Conformation Good General Health Daughter of Prolific Mother Free from hereditary defects Good Feet RAM Good Conformation Good General Health Performance Tested by dept. Very Good Feet
Pure breed If ram has been used the previous year and ewe labs retained –Ram has to go!!!!! Insure not Sterile, Ram reaches puberty at 6 months
Ram is half the flock. Growth rate Conformation Killing out % Leaness All are determined by the RAM breed (purebred/pedigree) Pedigree Texel Ram realised 220,000 Guineas Sept 2009
Ewe should be prolific Good mothering qualities. Flushing of ewe increases number of lambs. Reproductive efficiency. Belclare Improver
Old. Not prolific. Udder troubles (mastitis) Faulty teeth. Under size. Lambing difficulties. Low milk yield. Barren. Bad feet.
List 5 factors to be considered when selecting breeds. Name the factors when selecting ewes and rams. Consider the comment that “rams are for quality and ewes are for quantity”. When is it time to consider replacing the ewe?
Seasonally Polyoestrous Oestrous Sept-Feb Length 17 days Duration 36 hours Gestation Period 149 days (5 Months)
Sheep are seasonally polyoestrous. This means they come into oestrous repeatedly but only over a certain period or season of the year. This period is from early September to February The length of oestrous is 17 days The average duration of oestrous is 36 hours
The declining light levels in September act on pituitary gland. This stimulates Follicle stimulating hormone (FSH) This in turn stimulates the ovaries to produce oestrogen This begins the oestrous cycle.
Ewes should be in good condition – Condition Score = 3.5-4.0 High Conception rate results Technique = Flushing Moving sheep onto rich pastures 2 weeks prior to mating
Two weeks before mating the sheep should receive their winter dip (not before 15th September) Otherwise the sheep can receive the dip a few weeks after mating. The whole flock should be dosed for intestinal parasites (worms). The wool around the tail should be trimmed to facilitate service and avoid injury to the ram.
Ewes are stocked heavily on bare pastures 25/30/ha before weaning & mating A couple of weeks before mating nutrition is improved by stocking them less heavily 15/18/ha More eggs released at ovulation (twins) More regular heat periods Higher conception rates Better attachment to uterus
Ewe:ram 1:40 Ewe:ram 1:10 Rams must be kept away as they will fight Dates kept = lambing date Marker dye –every 17 days- Raddled Ear tagged 6-8 wks- all should be in lamb Suspect ram-cull
This is a technique used to induce ewes to lamb early enough for the lambs to be ready for the Easter market Prices are highest at this time Lambs born from September/October matings will not be ready for the easter market. Ewes must be brought into oestrous out of season, in July or August.
This involves placement of the progesterone- impregnated sponges. When the sponge is removed a single intramuscular injection of pregnant mares serum gonadotrophin (PMSG) is administered to the sheep.
Ewes are introduced to the ram in early Sept. for 8 weeks Heat & served at different times- lambing protracted Oestrous can be synchronised. Shorter mating & lambing periods Sponges are impregnated with progesterone into the ewes vagina & left their for 12 –16 days. The progesterone blocks the oestrous cycle If sponges are removed simultaneously all ewes come in oestrus 2 days later & are all mated together All lambs born same time (not protracted)
Detects mating behaviour in rams. Helps predict lambing date. Aids in detecting infertile ewes which is therefore useful for culling. Also identifies infertile ram. (if all ewes show 3 different colours). Colour changes every 17 days.
1. Explain the following terms: 1. Synchronisation. 2. Flushing 3. Sponging 4. Breeding out of season. 2. Outline the steps involved in preparing the flock for mating. 3. What is a raddling harness?
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