Leaving Certificate Agricultural Science

1. Leaving Certificate Agricultural Science Sheep

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. Sheep production in Ireland • 2 main types of sheep production systems in Ireland • Lowland sheep production (which we will study in detail) • Mountain/Hill production

6. Comparing Mountain/Hill and Lowland sheep production

7. Stages in the life of sheep

8. Breeds of sheep

9. Blackface Mountain • Mountain Breed • Low size and bodyweight • Small & Hardy • Very good mothers • Horned • Wool & breeding ewes • Mostly single lambs but can become prolific if crossed appropriately. • Mountains over 350m Kerry, Galway, Donegal, etc

10. Wicklow Cheviot • Mountain breed but more suited to fertile hills • White face and legs and good quality wool • Not as hardy as blackface nut are able to withstand mountain conditions • Good mothers that mainly have single lambs • Mountains Wicklow, Carlow, Kildare, Wexford

11. Galway • Lowland breed • Native breed of Galway and Roscommon • Very good wool production • Very large size & body weight • Late maturing and late finishing

12. Suffolk • Lowland breed • Distinctive black head and black legs • Conformation breed (good body shape) • Good wool production • High prolific breed

13. Suffolk

14. Texel • Lowland breed • White faced breed • Good conformation • Early maturing and finishing • Produces lean meat • Good prolificy

15. The Belclare Improver • Lowland breed • Maternal breed of medium size • Early maturing • Polled and white in colour • Produces high no of twin lambs

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

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

18. 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

19. 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

20. 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

21. Ewe for Quantity • Ewe should be prolific • Good mothering qualities. • Flushing of ewe increases number of lambs (see later). • Reproductive efficiency. • Belclare Improver

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

23. 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?

24. Gestation (don’t write) • Seasonally Polyoestrous • Oestrous Sept-Feb • Length 17 days • Duration 36 hours • Gestation Period 149 days (5 Months)

25. 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 • Gestation period is 149 days or 5 months

26. 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.

27. Preparing Stock For Mating • Ewes should be in good condition – Condition Score = 3.5-4.0 • High Conception rate results • Technique = Flushing

28. Flushing • This involves placing ewes on a low plane of nutrition after weaning followed immediately by a high plane of nutrition 3 – 4 weeks before mating • Advantages • More eggs released at ovulation (twins) • More regular heat periods • Higher conception rates • Better attachment to uterus

29. 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.

30. Mating • Ewe:ram 1:40 • During mating Ewe:ram 1:10 • Rams must be kept away as they will fight • Dates kept = lambing date • Marker dye or a raddle is used every 17 days • Ear tagged if paint is on ewe • 6-8 wks- all should be in lamb • Suspect ram-cull

31. 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.

32. Breeding out of season • This involves placement of the progesterone-impregnated sponges into birth canal of ewe for 12 – 16 days. • When the sponge is removed a single intramuscular injection of pregnant mares serum gonadotrophin (PMSG) is administered to the sheep. • Two days later, all ewes come into heat

33. Sponging • Ewes are introduced to the ram in early Sept. for 8 weeks • Heat & served at different times- lambing protracted • Oestrous can be synchronised. • 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)

34. 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.

35. 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?

50. 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