Quiz 3 Flashcards
Outline the advantages of Autumn lambing in a prime lamb production system in southern NSW.
Higher lamb prices due to it being off season.
Higher quality of feed when finishing off as this aligns with Spring flush.
Low fly strike rates.
Outline the disadvantages of Autumn lambing in a prime lamb production system in southern NSW.
Higher mortality rate due to colder climate.
Rely on winter rainfall for pasture growth, if there isn’t enough supplementary feeding may be required until spring flush, increasing production costs.
Shorter days and sunlight, out of season breeding.
Outline why border Leicester-Merino cross ewes are preferred as prime lamb mothers over purebred Merino ewes.
Hybrid vigour.
Merinos have poor mothering ability, smaller size and low fecundity. BL have moderately high fecundity, larger size, high growth rates and good carcass shape and contribute these characteristics to their crossbreed offspring.
Merinos in BCS3 wean 80% lambs, BL in BCS3 wean 120% lambs.
Describe the two tiered production system of prime lamb production.
First tier involves merino ewes being mated to Romneys or BL Rams. These crossbreed ewe progeny are then mated to a terminal meat sheep sire such as poll Dorset, Texel or Suffolk to produce second cross progeny to be sold as meat lambs.
Provides more efficient meat production due to hybrid vigour gained from previous crosses.
Name 3 breeds of sheep that are commonly used as sires for prime lamb production in Australia. Briefly outline the key characteristics of each breed.
Texel-lean breed of medium size with long, rectangular body. Medium bone structure, pronounced muscling and good growth rates. Excellent carcass quality.
Poll Dorset-shorter boned with compact frames, account for over 70% of lambs produce in Aus. High growth rates and good shaped carcass.
Suffolk-well muscled, lean with good growth rate, Rams have high fertility even in hot summer conditions and excellent libido, allowing for lower ram to ewe ratio.
Explain the meaning of DSE. For what purpose can it be used and what are its limitations?
Dry sheep equivalent. 1 DSE=feed requirements of adult 50kg, 2yo wether for maintenance.
Purpose to compare feeding requirements of different classes of stock, assess carrying capacity, assess potential productivity of farm or patch of land.
Limitations involved include assumptions that have been placed on variables including climate, topography, pasture quality and quantity, water availability.
Describe why animal health and welfare is an important priority for sheep enterprises in Australia.
Animal health and welfare are important as they provide a benchmark for farmers and encourage them to produce the best quality product using the best welfare practices as per the 5 freedoms. Important for sheep as there are range of practices during production that can negatively impact welfare-marking, mulesing, etc.
Improper management can lead to poorer production, negatively affecting end product and damaging international trade.
Describe the best practice procedures for marking in a spring lambing merino flock in southern NSW.
Marking done as early as possible to minimise pain to animal, ideally prior to weaning (approx 6wks old, NOVEMBER). Ear marking uses applicators in good working order, disinfect between animals, adequately restrained head with tag applied to centre of ear away from longitudinal ridges. Castration either surgically with sharp, sterilised lamb marking knife or via elastrator method. If older than 6months vet must be used.
Tail docking done using sterilised lamb marking knife, gas heater de-tailer, elastrator rings. Severance occurs level with tip of vuvla or below second palpable tail joint. If using knife, bare skin beneath tail should be pushed forward just prior to severance, leaving flap of skin to heal over bottom of cut tail.
Lambs should not be marked if showing signs of overheating or over excitement-excess bleeding. Should not be held in yards, ewes should have adequate water to reduce risk of deserting lambs upon release from yards. Ewes up to date with tetanus vaccine to ensure lambs have immunity.
Describe recommendations you would provide to producer for weaning her lambs in a spring lambing prime flock near Wagga.
Don’t wean til youngest are at least 8wks and above 20kgs. Wean early December, post marking. Depending on state of pasture may need to supp feed with high protein ration (grains-oats, lupins, lamb pellets) to ensure weight gain continues. Ensure water and shade are easily accessible due to summer conditions. Frequently check health and welfare-particularly fly strike. Release onto low worm pasture.
Describe the recommendations you would provide to a producer for weaning his lambs in a spring merino flock near Wagga.
Wean early December post clutching and mulesing at marking. Paddocks should be high quality feed, low grass seed infestation, low worm risk and good quality stock water. Away from ewes with good fences. No contact with other mobs on property.
What are the main factors that influence lamb growth and discuss how they can be optimised.
Two main factors; birth weight and nutrition. Nutrition affected by level of ewe lactation, wether she has twins or single lamb, condition score of ewe at lambing, current nutritional status of ewe and her fat reserves.
Difficult to optimise birth weight due to uncontrollable factors, ensuring ewe is receiving 1.7X maintenance daily in last trimester increases likelihood of healthy lamb.
Nutrition optimised by ensuring ewe is receiving adequate energy for lactation. Producing 2-3kg milk requires 20-30MJME daily. Ensuring lamb is receiving milk is important, lambs require 1.5kg for maintenance, every kg afterwards sustains growth rate of approx. 330g per day, decreasing to 270g later in lactation.
What are nutritional requirements for lactating ewes?
2-2.5X maintenance.
Maintenance is 8-10MJME
Discuss how nutritional requirements for lactating ewes can be met and monitored in an Autumn lambing flock in northern Victoria.
Condition scoring is an important tool for monitoring ewe nutritional status and body reserves, if condition is dropping to low 3 or less supplementary feeding should commence to meet energy requirements for both ewe and lamb.
If adequate rain hasn’t fallen over Autumn the pasture quality is low and supp feeding and irrigation may also be necessary.
Feed intake peaks 8wks post lambing so ewes should be properly monitored over this phase.
Discuss advantages and disadvantages of different lamb finishing systems.
Three forms; pasture, lambs finished on crop residue, lamb lot feeding. Pasture systems need to time with spring flush to ensure adequate feed for either the weaned or sucker lambs. Sucker lambs are low maintenance and rely on nutrition of the ewe and her milk production for growth while weaner lambs are sold as heavier carcass lambs and have higher management needs.
Lambs finished on crop residue is cheap alternative to feedlots, often lack in energy and protein and so require supp feeding. Lupin stubble is often used as higher energy and protein however risk of lupinosis.
Lamb lot feeding provides consistent supply of quality lamb all year to consumers. Not reliant on rainfall and pasture growth. Lot feeding utilises ‘feeder lambs’ from specialist producers only, labour intensive, higher disease risk due to high density of animals.
Describe steps involved in clinical exam of sheep.
History-flock/mob, farm husbandry and practices.
Group/mob examination-from distance in paddock or large yard. Determine proportion of affected animals, severity of problem. Another opportunity to gain more history and asses farm practices.
Single out affected sheep after having observed them from distance. Assess body condition, use 5Ts as basic structure for close up exam.
What are anthelmintics used for in sheep?
Anti parasitic drugs used to treat and control internal parasites such as worms and liver fluke. Administered in form of drenches.
List common groups of anthelmintics available.
Broad spectrum/Major: benzimidazoles (white drenches), levamisole/morantel (clear drenches), macrocyclic lactones (MLs)/mectins.
Narrow spectrum/minor: organophosphates (naphthalophos), triclabendazole, salicylanilides (closantel, oxyclozanide).
Combination drenches - benzimidazole and levamisole, albendazole and closantel. Act on multiple parasites at different stages.
Discuss important considerations when using anthelmintics and the reasons.
Dose appropriate to body weight, consistent under or over dosing leads to resistance.
Certain drenches can be lethal if overdosed-organophosphates.
Dose only when required-faecal egg count.
What are vaccines used for in sheep?
Vaccination allows protection against some of the common and serious infectious diseases via the stimulation of antibodies against the particular disease. Allows protection against production loss.
List some common types of vaccines used in sheep.
Clostridial-5 in 1 or 2 in 1. Cover against enterotoxaemia(pulpy kidney), tetanus, blacks disease, blackleg, malignant oedema.
Caseous lymphadenitis (CLA, cheesy gland)-in combination with clostridial vaccines, 6 in 1 or 3 in 1.
Scabigard, Gudair, anthrax.
What are important considerations when using vaccines and why?
Herd immunity can be obtained by vaccinating 70-80% herd. Only administer to healthy animals, majority are SC and should be administered in areas with easily accessible skin where they won’t affect meat quality.
Care needs to be taken by administrator to not inject themselves.
Vaccines need to be stored in fridge and out of direct sunlight.
Administration at appropriate times important to ensure adequate immunity-annual boosters. WHP considered.
