Lameness Management of Replacements (in a maternal flock) and fattening lamb management

Single bit of advice If you don’t like something about a ewe in your flock, or don’t like doing a particular job. Choose replacements that are not off-spring of those sheep and do not need those jobs done to them.

I.e. If you don’t want to spend the rest of your life dagging sheep don’t breed from the ones that need dagged

What is this term?

Replacements Purchased: Simple Often hybrids so have hybrid vigor In essence subcontracting the rearing, the genetic selection, disease status to someone else- are they doing what you need ??

Homebred: Complex -may involve several flocks Selection –genetics, phenotype Frequently purebred no hybrid vigor

What is this term?

EID may mean that you can trace an issue to a breeder and not buy their stock again Disease- if seller has 1% OPA prevelance in flock and you buy 100 ewe lambs over 2-3 years almost certain to buy in disease. Arguments over cost of homebred vs purchased

Hybrid vigour more difficult to maintain with homebred sheep

What is this term?

Replacements Profitably: Ewe mature weight (20kg carcass needs a 60-65kg ewe) Number of live lambs sold Growth rate of the lambs

For a talk on what makes an efficient ewe see SBRT: https://www.premier1supplies.com/sheep-guide/wp-content/uploads/2013/04/Viponds-efficient-sheep-talk.pdf

This excludes costs –many of which are optional

What is this term?

Homebred Probably takes 10 years to change a flock Tup selection Nucleus flock of ewes? Remember epigenetics Breed as ewe lambs or as gimmers?

NEVER, Ever keep the tail end lambs, Probably never keep the first, biggest lambs as they are singles.

The longest lived sheep are usually the non productive ones

What is this term?

Breeding from ewe lambs Lifetime productivity increased by 10% (carbon advantage) May live less long (but still more productive) If they breed in their first year they are more productive sheep – Require more feeding during pregnancy and lactation If they rear twins in the first year more likely to have a single the next year if nutrition not optimal Probably better mothers More work in that first year at lambing More Mastitis Mortality rate higher than in mature ewes

Worth using a Shetland –low lamb value but low work 10% Less greenhouse gases Low productivity ewes live longer than high productivity ewes- costs per lamb drop by 40% with a twin lamb vs a single Breeding in the first year may also be associated with lower mature size

What is this term?

Selection of ewe lambs- thoughts The thought to have in mind is choose the twin lambs ready (for the farm output) earliest from the smallest ewes with the best production histories and least interventions

What is this term?

Selection of ewe lambs- those most likely to breed 60 % of mature weight at tupping time (cf gimmer 80%) BCS 3 Healthy

What is this term?

Selection of ewe lambs- Those that will have enhanced productive lives Twin Never select lambs with weights less than 10% below the cohort mean weight Always lambs that were born in the first tupping cycle Avoid lambs born to ewes that went through a nutritional / disease challenge in pregnancy May want to cull 20% ewe lambs that are barren

Cohort consists of the females as these are 10% lighter than males (very approximately)

What is this term?

Selection of ewe lambs- for future health Choose lambs that needed no support/interventions Physically sound TST – lambs that grew but did not need tx (Resilience to Parasites and no growth check) FEC, or better, salivary IgA test SNP chip?

What is this term?

Maternal traits Number of lambs born Number of lambs surviving Weight of lamb at 8wks (equivalent to milk yield) Mature size (Ratio of ewe weight to that of her weaned lambs) (Health and longevity of the ewes) These are impossible to assess by eye, so one needs data, years of data, ideally EBV’s eg Signet, Sheep Ireland, SIL in NZ, National Sheep Improvement Program in the US.

Can do this on farm with raw data – but not as accurate as EBV’s which also permit a benchmark vs other breeders if one wishes to buy genetics in. Genomics will probably become very important in the future as they will accelerate this selection.

What is this term?

Replacements Most precious resource on the farm do NOT take any risks Good health plan –be conservative (risk adverse) with this group Vaccinations-clostridia +Pasteurella Abortion vaccines? Worm + Fluke control (remember type II ostertagiasis)

What is this term?

Tupping and post tupping management Avoid grazing on red clover Probably don’t flush to avoid twins From the initial 60% of mature body weight at tupping, aim to add 5kg through to lambing then up to 80% adult weight at second tupping. Too rapid growth during pregnancy depresses milk production and lamb birth weight, hence lamb survival

What is this term?

Weaning- When? Ideally lambs 25-30 kg at weaning. Minimum of 16 kg and 9 wks. Usually a growth check at weaning

Growth check minimized by: Late weaning Weaning unto familiar pasture and diet (ie move ewes away from lambs)

What is this term?

Weaning-When? Early weaning (lambs growing less than 200g/d) If forage is short- target this at the lambs Ewes thin

Late weaning If plenty of forage If lambs just under killing weight

What is this term?

Weaning-problems Pasteurellosis Parasites-fluke/ telodorsagia / trichostrongylus, primarily but can get nematodirus Grain overload Brassica issues Red clover – copper toxicity Lameness Coccidiosis Clostridial diseases

Diseases are more significant in replacements than with fattening animals because of the lifelong impact- same as suckler calves if the business model is buying in lambs to finish them

What is this term?

Weaning- crops The one time in life that dose and move may be appropriate. But these sheep cannot then go anywhere that they can cause infection in other sheep. (Field is always ploughed afterward –never grazed).

What is this term?

Weaning- crops Brassicas: Photosensitisation Nitrate poisoning- usually rain after a drought Goitre (unlikely in lambs) Anaemia –S-methyl-cysteine sulphoxide highest in flowers and young leaves- heinz-body anaemia with jaundice and haemoglobinuria Oxalate poisoning- hypocalcaemia acutely or renal failure chronically Sulphur and molybdenum levels are high Clostridial diseases Introduce slowly, ensure a grassy run back area and possibly ensure brassicas only form part of the diet.

What is this term?

Weaning- crops Chicory- bioactive anthelmintic effects Cereal stubble Grass silage aftermaths Plantains

What is this term?

Finishing lambs

From RUMINANT NUTRITION Andy Macdonald and Chris Kneale: https://www.gov.im/media/172425/nutrition_presentation.pdf

What is this term?

Further reading BCS https://www.youtube.com/watch?v=8KoRzvA-cfY

Benefits of recorded genetics https://www.fas.scot/downloads/using-estimated-breeding-values-in-sheep/

Growing and fattening lambs: https://projectblue.blob.core.windows.net/media/Default/Imported%20Publication%20Docs/AHDB%20Beef%20and%20Lamb/GrowingAndFinishingLambs2024_WEB.pdf

Replacements: https://ahdb.org.uk/knowledge-library/selecting-ewe-lambs-for-breed