Leaving Certificate Agricultural Science

1. Leaving Certificate Agricultural Science Sheep - 1

2. Learning Outcomes... • 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.

3. Sheep Facts • 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

4. DENTAL FORMULA- Sheep • Incisors, Canines, Premolars, Molars. 0 0 3 3 4 0 3 3 X 2

5. Mixed Grazing of Cattle & Sheep • 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

6. Learning Check... • State the length and duration of the oestrous cycle. • What is length of gestation? • Name the phylum that sheep belong to. • State the dental formula foe a sheep. • What is mixed farming? • Give the advantages of mixed grazing.

7. Breeds • 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

8. Breeds- Classification • Prolific breeds- Belclare Improver • Carcass breeds- Suffolk, Texel • Cross breeds: • Ewe breeds- Galway, Blackface Mountain and Cheviot.

9. Blackface Mountain • Mountain Breed • Ewe Breed • Small & Hardy • Able to withstand mountain conditions • Horned • Wool & breeding ewes • Become prolific if crossed appropriately. • Mountains over 350m Kerry, Galway, Donegal, etc

10. Wicklow Cheviot • Mountain Breed • Small • Not as hardy as blackface • Able to withstand mountain conditions • Wool & breeding ewes for lowland fattening. • Mountains Wicklow, Carlow, Kildare, Wexford

11. Galway • Lowland • Native breed • Live in a less severe environment • Big & Late maturing • Wool, Fat lambs & hogget mutton & breeding ewes

12. Suffolk

13. The Belclare Improver • Cross between Galway & Finnish Landrace –to improve prolificy • X & Llynn –to improve conformation

14. Learning check... • Name 3 categories of breeds. • Name 4 breeds. • Give their characteristics.

15. Breeding Strategy • 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

16. Selecting Breeds • Good Carcass • Good Conformation • Good prolificy. • Wool/ewes/meat • Feed: fertility is increased with high quality feed

17. Ewe & Ram Selection • 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

18. RAM Selection • 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

19. Ram for Quality • 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

20. Ewe for Quantity • Ewe should be prolific • Good mothering qualities. • Flushing of ewe increases number of lambs. • Reproductive efficiency. • Belclare Improver

21. Time to replace ewe if: • Old. • Not prolific. • Udder troubles (mastitis) • Faulty teeth. • Under size. • Lambing difficulties. • Low milk yield. • Barren. • Bad feet.

22. Learning Check.... • 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?

23. Gestation • Seasonally Polyoestrous • Oestrous Sept-Feb • Length 17 days • Duration 36 hours • Gestation Period 149 days (5 Months) 149 Days

24. Oestrous cycle • 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

25. Oestrous cycle • 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.

26. Preparing Stock For Mating • 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

27. Before 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.

28. Flushing • 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

29. Mating • 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

30. Breeding out of season • 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.

31. Breeding out of season • 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.

32. Sponging • 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)

33. Raddling Harness • 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.

34. Learning Check.... • Explain the following terms: • Synchronisation. • Flushing • Sponging • Breeding out of season. • Outline the steps involved in preparing the flock for mating. • What is a raddling harness?