Animal Sciences Commons^™

Lambing Performance Of Morlam And Dorset Ewes Under Accelerated Lambing Systems, L. C. Iniguez, R. L. Quaas, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Two accelerated lambing systems, Morlam using Morlam sheep (USDA, Beltsville 1966 to 1975) and Carnal using Dorset ewes (Cornell 1978 to 1981), were evaluated for first lambing ages, interlambing intervals and conception probabilities. Morlam ewes were continuously exposed to rams over the year, while Carnal Dorset ewes were exposed every other month. Morlam lambs were mated as early as 367 d of age and Carnal Dorset lambs as early as 340 d. Early lambing was associated with higher rates of perinatal mortality (P>.05) and smaller litter size (P<.O1). Lambing years among Morlam ewes and season of birth of Carnal Dorset ewes influenced (P<.01) their first lambing ages. Lambing intervals averaged 293 and 303 d among Morlam and Carnal Dorset ewes, respectively. Age at first lambing and season in which the previous lambing occurred with influential factors (P<.01) on lambing intervals of Morlam ewes; longer intervals resulted when ewe lambs were mated at early ages (<12 mo), and when the previous lambing occurred in winter. Estimates of conditional probabilities of conception by month given the occurrence of estrus, reflected seasonal changes in both systems. The overall probability of conception for the Morlain system (P=.16) was relatively higher than that for the Carnal Dorset system (P=.14); numbers of lambings per ewe per yr were 1.28 and 1.21, respectively. Estimates of heritability for age at first lambing, lambing interval and conception probability were. 31, .06 and .30, respectively.

Survey Of Parasite Control Practices In Sheep And Cattle, J R. Edwards, R V R Gwynn, R A. Love, Richard Thomas Norris, G Dalton-Morgan, Brown Besier

Technical Bulletins

Farms in the Albany, Esperance, Jerramungup and Katanning districts were surveyed to determine parasite control strategies currently used, to evaluate the adoption of recommended control practices and to detect areas of ineffective parasite control. For cattle, the number of drenches given in the low rainfall zone was higher than the number given in the high rainfall zone.

Ovulation Rate Of Ewes : Role Of Energy And Protein, E Teleni, J. B. Rowe

Journal of the Department of Agriculture, Western Australia, Series 4

Western Australia's sheep farmers are familiar with the low ovulation rate of Merino ewes and how this limits the lambing performance of ewe flocks.

One way in which ovulation rate and therefore lambing percentage may be increased is to feed seed of sweet lupin (Lupinus augustifolius) to ewes at mating. However, Department of Agriculture research has found that these increases do not show up consistently, and that there is considerable variability between farms.

If improved nutrition is to be a useful way to increasing ovulation rate, the mechanism by which nutrition affects ovulation rate must first be understood. This article …

Control Strategies For Annual Ryegrass Toxicity, W J. Burdass

Journal of the Department of Agriculture, Western Australia, Series 4

In 982-83, annual ryegrass tocicity (ARGT) was estimated to have cost Western Australian sheep farmers between $7 and $8 million in total economic losses.

The disease can severely disrupt farming operations. Sheep must be checked daily and if affected moved to a 'safe' paddock. The availability of paddock feed is reduced, as is stock carrying capacity. Worry about the possibility of dramatic stock losses, and uncertainty about what decisions to make, are all stressful.

Stock losses from ARGT can be minimised by the use of selective herbicides to control ryegrass in pastures and crops. This breaks the disease cycle - …

Pregnancy Diagnosis Using Ultrasound, M A C Johns

Journal of the Department of Agriculture, Western Australia, Series 4

Few Western Australian ewe flocks are diagnosed for pregnancy despite the precence of high numbers of barren ewes. Surveys of farm flocks in the early 1970s recorded that between 14 and 29 per cent of ewes failed to lamb each year.

Techniques for diagnosing pregnant ewes have been available for many years, but ultrasonic devices and computer technology have made it possible for skilled operators to determine whether ewes are pregnant and more importantly, whether they have one, two or more foetuses.

Once the number of pregnant ewes is known farmers can use labour more efficiently. They can minimise the …

Reproductive Wastage In Sheep, R W. Kelly

Journal of the Department of Agriculture, Western Australia, Series 4

The average lambing performance of Western Australia's ewe flock fluctuates between 60 and 70 per cent. Although this level of performance and variation between years is important for the sheep industry, individual farmers are more concerned about performance of their own flocks.

Figure shows the range in lambing performances that exist between farms in this State in 1983-84. The seriously poor performance of many flocks is apparentm - 28 percent of farms had less than 60 per cent lambing. By contrast, 24 farms had performances better than 100 per cent. The reasons for the large differences between farms ( and …

Survey Of Post-Weaning Management, Growth And Mortality Of Merino Weaners, Richard Thomas Norris

Technical Bulletins

Flock owner's excessive use of supplementary feed, especially of hay, lack of knowledge of nutritional requirements of weaners and failure to follow recommended methods of internal parasite control were the main areas of inefficient management. Management of the weaners as observed in the first year, suggested that previous advice by the Department of Agriculture was not well accepted or had not reached some producers.

More Lambs From Feed And Chemical Treatments, K P. Croker

Journal of the Department of Agriculture, Western Australia, Series 4

The ovulation rate, or the number of eggs shed per ovulating ewe, represents the upper limit of the capacity of a flock of ewes toproduce lambs. Several methods can be used to increase ovulation rates and lambing percentages of ewes, including selection for better breeding, feeding and the use of chemicals.

The potential for improving the reproductive performance of Western Australia's ewe flocks by the use of different approaches to breeding was discussed by L.G. Butler and R.P. Lewer in the Journal of Agriculture in 1983.

This article mainly discusses the research conducted by the Department of Agriculture's Sheep and …

Bulletin No 4101 - Flystrike - A Manual For Its Prevention And Control, N Monzu Dr

Bulletins 4000 -

The sheep blowfly is still regarded as the Australian sheep industry's most­damaging pest. Estimates of the cost to the industry, through production losses and prevention and control measures, exceed $ I 00 million in a year. This bulletin comprises the most relevant information available on:

• Blowfly types and life cycles

• Conditions predisposing sheep to flystrike

• The mechanism of flystrike

• Methods of preventing and controlling strike.

• Current research - including the development of a forecasting system for body strike.

Footrot In Sheep And Goats, Department Of Agriculture, Western Australia

Animal production and livestock published reports

Reference to sheep in this pamphlet applies equally to goats.

Footrot is a contagious disease of sheep and goats caused by the bacterium Baueroides nodosus.

The bacterium can cause varying degrees of damage to the horn of the foot. The resulting infection can lead to lameness and serious loss of body condition.

A Survey Of Drench Resistance In Sheep Worms, J R. Edwards, R. Wroth, G. C. De Chaneet, R. B. Besier, J. Karlsson, P. W. Morcombe, D. Roberts, G. Dalton-Morgan

Journal of the Department of Agriculture, Western Australia, Series 4

Sheep worms which are resistant to chemical drenches have been detected with increasing freuency is Western Australia's south-western farming areas between 977 and 1980. These worms have anthelmintic resistance and such genetis resistance puts essential internal parasite control practices at risk.

This prompted veterinarians in the Esperance, Albany, Bunbury, Geraldton and Northam areas to survey farms to determine the prevalence of resistance to drenches and to define those sheep management practices which encourage its development.

This article describes the survey which was conducted to assess the extent of drench resistance, what causes its build-up and how it can be controlled …

'Dermo' Fleece Rot And Body Strike On Sheep, S G. Gherardi, S. S. Sutherland, N. Monzu

Journal of the Department of Agriculture, Western Australia, Series 4

Blowfly strike is one of the major problems confronting the sheep industry in Austrsalia, with an estimated totsalcost of control eceeding $100 million each year.

Sheep are susceptible to five types of strike: body, breach, poll, pizzle and wound. Body strike, is of greater economic importance because its sporadic occurence from year to year makes it difficult to predict and cintrol. Outbreaks of body strike after rain can affect large numbers of sheep and inflict severe production losses.

In eastern Australia fleece rot is generally considered to be the main predisposing factor to blowfly strike, but in Western Australia evidence …

Protecting Off-Shears Sheep In Adverse Weather, T M. Ellis

Journal of the Department of Agriculture, Western Australia, Series 4

In January 2982 in the Narrogin-Darkan area of Western Australia, about 14,500 sheep up to 40 days off-shears died after a 48-hour period of heavy soaking rain that followed a thunderstorm three days previously. An estimated 100,000 sheep died throughout the South-West at the time.

P. G. Buckman - at the time Department of Agriculture District Veterinary Officer, Narrogin - surveyed 17 properties in the area. He found that losses in unshedded sheep 0 to 40 days off-shears ranged from 0 to 84 per cent of sheep on the property with an overall average of 27.9 per cent. Rainfall in …

Dispelling Some Myths About 'Dermo', J R. Edwards

Journal of the Department of Agriculture, Western Australia, Series 4

There are a lot of misconceptions and myths about dermatophilosis, a disease which can kill young lambs, affect wool quality, make shearing difficult and make sheep susceptible to fly strike.

One misconception is perpetuated by the incorrect use of the name mycotic dermatitis, which implies that a fungus causes the disease. This is not so.

The disease is caused by the bacteria Dermatophilus congolensis, which attacks the sheep's skin and eventually forms a lesion or scab in the wool, and so is better called dermatophilosis, 'dermo' or 'lumpy wool'.

Veterinary Epidemiologist at the Albany Regional Office, J.R. Edwards, discusses …

New Developments In Footrot Control, R B. Richards, L. J. Depiazzi, R. V. R. Gwynn

Journal of the Department of Agriculture, Western Australia, Series 4

The eradication policy for footrot in sheep adopted by the Western Australian Department of Agriculture has produced an overall decline in the number of properties with the disease.

Our knowledge of the disease has improved substantially as a result of the research conducted at the Slabany Regional Veterinary Laboratory in recent years. Laboratory tests now sssist stock inspectors and veterinary officers to distinguish between different forms of footrot and to quarantine and eradicate accordingly.

The recent discovery of more effective foot-bathing solutions by officers of the Victorian Department of Agriculture will greatly assist further eradication procedures.

Western Australia's sheep industry …

Bulletin Ma 20 - Sheep Yard Plans - Flocks Up To 500, D. Bicknell

Animal production and livestock published reports

Manjimup Regional Office

Owners of small flocks often use much more labour per sheep than do owners of large flocks. Most of the difference in labour use is the design of sheep sheds and sheep yards, and a smaller affect from the mob size and experience in handling sheep.

This booklet gives some detail on design and construction of yards and a number of yard plans to handle up to 500 or so sheep. Many of the plans are from an Australian Wool Corporation publicatiot1 "Wool Harvesting Notes".

Electronic Feeding Doors For Individual Feeding Of Group Housed Sheep Compared To Individual Housing And Feeding Or Group Housing And Feeding, Ronald J. Lane

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Thirty-six mature purebred cheviot ewes and 36 polypaysired wether lambs were used in two separate experiments to determine the usefulness of an electronic feeding door as contrasted with traditional feeding situations. The sheep were stratified by weight into three management categories; group housing and feeding (G+G), individual housing and feeding (1+1), or group housing and individual feeding (G+1) using an electronic feeding door. The weight stratification formed a light and a heavy weight class resulting in a 3x2 factorial design. Two different training procedures were used to arrive at a generalized 14-day training sequence that does not require physical handling …

Reproductive Behavioral And Physiological Traits In Domestic, Wild, And Hybrid Ovis, Kara-Lynn Crocker-Bedford

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study was part of a program to develop new genotypes of sheep (Ovis spp.) and goats (Capra spp.) which are more useful for food and fiber production. The study examined the influence of domestication on behavioral and physiological traits of ewes and lambs, the influence of a single or twin offspring on ewe and lamb behaviors, and general relationships between ewes and lambs during the lambs' first month of life.

Domestication has caused the intensities of observed traits to diverge greatly from the tendencies shown by wild populations. Domestication has produced increases in measurements associated with maternal …

Linear Models For Estimating The Nutritive Value Of Sheep Diets, Michael L. Christiansen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Digestibility data were determined in 2 replications of a 2 x 3 x 2 x 2 factorial arranged experiment to: (1) determine the effects of forage type (grass vs alfalfa), forage maturity (late vegetative vs midbloom vs fullbloom), diet ingredients (forage only vs 50:50 forage plus corn), and diet texture (coarsely chopped vs pelleted) on the digestibility of diet chemical constituents by sheep; (2) develop equations to estimate digestible energy of sheep diets from nutrient content of the diet; and (3) compare popular chemical methods used to partition feed dry matter into fibrous and soluble components. Diets were fed to …

More Lambs By Mating Weaners, R J. Suiter

Journal of the Department of Agriculture, Western Australia, Series 4

Farmers can increase sheep numbers by mating ewe weaners. Trials have shoen that this does not affect the later performance of these ewes.

Diagnosing Pregnancy In Sheep : The 'Scanopreg', R H. Wroth, M. J. Mccallum

Journal of the Department of Agriculture, Western Australia, Series 4

The "Scanopreg", an ultrasonic machine for diagnosing pregnancy in sheep, is effective as early as eight to nine weeks of pregnancy, and could therefore be a useful management tool.

Lupinosis : A Disease Still With Us, Jeremy G. Allen, P. Mcr. Wood, K. P. Crocker, J. Hamblin

Journal of the Department of Agriculture, Western Australia, Series 4

Current research on lupinosis continues to reveal what a complex problem it is, but the improved understanding should help to reduce losses.

Flystrike In Sheep : Secondary And Tertiary Flies Striking Sheep In Western Australia, N Monzu

Journal of the Department of Agriculture, Western Australia, Series 4

Unlike primary species of blowflies, the secondary and tertiary species of flies cannot initiate a strike, but their activity in the presence of the primary blowflies becomes significant in the death of struck sheep. This is particularily so when the hairy maggot blowfly is involved. Future management of sheep flocks to minimise deaths may require recognition of these secondary and tirtiary flies.

This article presents some basic facts about these flies.

Rejections Of Sheep And Lamb Carcasses Are Costly, R H. Wroth, R. J. Suiter

Journal of the Department of Agriculture, Western Australia, Series 4

A 1976 survey of more than 48 000 sheep and 25 000 lambs slaughtered at two of Western Australia's export abattoirs has indicated a high rejection rate for W.A. carcasses. Rejections may be for disfiguring, blemishes requiring trimming or for diseases which can lead to condemnation.

Savings that producers can make by simple management changes, could thus save the industry $3.12 million a year. Reduction in other causes of rejection or further reduction in some of those mentioned id feasible but requires more research and may be more difficult to achieve.

New Policy Hits Hard At Sheep Lice, F C. Wilkinson

Journal of the Department of Agriculture, Western Australia, Series 4

In March 1977 the regulation requiring compulsory routine dipping of all sheep within 30 days of shearing changed, and only infested flocks were required to be dipped. This change has allowed concentrated eradication efforts.

Some Basic Facts About Primary Blowflies, N Monzu

Journal of the Department of Agriculture, Western Australia, Series 4

Research has begun on blowfly species attacking sheep in Western Australia. Already this research has indicated the importance of a species in Western Australia which is not a problem in the Eastern States.

Future management of sheep flocks to minimise fly strike may require recognition of the differences between blowfly species. This article gives a description of the primary species - those which can initiate strikes.

Crutching Cradles Can Work Well, N M. Marney, R. A. Mills

Journal of the Department of Agriculture, Western Australia, Series 4

Crutching cradles allow successful do-it-yourself crutching if a continuous flow of sheep can be maintained. This article describes some units available and discusses costs.

Controlling Annual Ryegrass Toxicity, C H. Trotman

Journal of the Department of Agriculture, Western Australia, Series 4

Eight years of intensive work has changed annual ryegrass toxicity from an unknown killer to a manageable problem.

The Philosophy Of Drenching Sheep In Western Australia, G C De Chaneet

Journal of the Department of Agriculture, Western Australia, Series 4

Sheep of all classes are drenched more or less regularly throughout the agricultural areas of Western Australia.

Much of the drench is wasted because it is used in the wrong circumstances. This situation is probably a result of poor understanding of drenching.

This article discusses the philosophy of drenching and attempts to relate this to the epidemiology of parasitism as it is currently understood.

Annual Dipping Is A Costly Business, F C. Wilkinson

Journal of the Department of Agriculture, Western Australia, Series 4

When sheep dipping was compulsory, lice infestations and their control could have been costing the sheep industry in Westrn Australi as much as $8 million a year.

On March 1, 1977 compulsory annual sheep dipping ended.

This raises the question of whether an owner should dip sheep.