Production benefits of breeding for worm resistance in Merino sheep

2020 ◽  
Vol 60 (13) ◽  
pp. 1643
Author(s):  
J. C. Greeff ◽  
L. J. E. Karlsson
Keyword(s):  
Mixed Model ◽  
Production Systems ◽  
Control Line ◽  
Cross Contamination ◽  
Resistant Line ◽  
Merino Sheep ◽  
Associated Production ◽  
Sheep Production ◽  
And Control ◽  
Production Losses

Context Production losses, due to worms and anthelmintic costs to control the infection, can affect the profitability of sheep production systems. Aims This study was carried out to quantify the production benefits of worm-resistant sheep. Methods Genetically worm-resistant and unselected control Merino rams were mated annually to 150 ewes in each of the Resistant and Control lines respectively over an 8-year period. All ewes and their progeny were managed in small replicated paddocks to prevent any cross-contamination between paddocks and groups. Fertility, growth, wool production, wool quality and worm resistance were measured on the ewes and their progeny. The data were analysed using mixed model methodology. Key results The progeny of the Resistant sires were on average 21–25% more worm resistant than the progeny of the Control sires. No significant differences were recorded in reproduction between mature ewes of the Resistant and Control lines, or in the survival rate of their lambs. Resistant line progeny were on average 1.6 kg heavier at weaning, received 15–17% less drenching during the experiment and produced on average 0.3 μm finer wool at hogget shearing than the Control line progeny. Conclusions It is concluded that the Resistant line coped better with a worm challenge and that this resulted in increased production. Implications This study shows that apart from improved worm resistance, there are associated production benefits in breeding for worm resistance.

Comparative water consumption and efficiency in three divergent sheep types

1995 ◽  
Vol 124 (1) ◽  
pp. 139-143 ◽  
Author(s):  
S. J. Schoeman ◽  
J. A. Visser
Keyword(s):  
Weight Gain ◽  
Water Consumption ◽  
Production Systems ◽  
Merino Sheep ◽  
Ewe Lambs ◽  
University Of Pretoria ◽  
Body Weights ◽  
Sheep Production ◽  
The University ◽  
Absolute Basis

SUMMARYCumulative feed and water intakes and body weights of 30 growing ewe lambs of three different breeds were recorded weekly for 34 weeks between October 1990 and June 1991 at the Experimental Farm of the University of Pretoria. The results were analysed to obtain water efficiencies on both an absolute and metabolic weight gain basis. On an absolute basis, Mutton Merino sheep consumed 145% and Dorper 109% more water than Blackhead Persian sheep. On a metabolic weight gain basis, the corresponding differences were 92 and 66%, respectively. Mutton Merino and Dorper lambs also consumed 69 and 41% more water per kg feed intake than the Blackhead Persians, respectively. Weekly water consumption increased twice as much per 1 °C increase in ambient temperature in the Dorper and Mutton Merino lambs as in the Blackhead Persians. These results suggest that sheep of the Blackhead Persian, and probably also other indigenous breeds, balance their water requirements at a more economical level and would be a more appropriate choice than those breeds currently being managed in sustainable sheep production systems in areas where water availability is limited.

Strip grazing to control wool growth rate of sheep grazing green annual pastures

1999 ◽  
Vol 39 (3) ◽  
pp. 247 ◽  
Author(s):  
J. Young ◽  
P. T. Doyle ◽  
P. Booth
Keyword(s):  
Growth Rate ◽  
Production Systems ◽  
Fibre Diameter ◽  
Matter Content ◽  
Stocking Rate ◽  
Merino Sheep ◽  
Wool Growth ◽  
Staple Strength ◽  
Sheep Production ◽  
Strip Grazing

We compared strip grazing (SG) as a means of controlling wool growth rate, reducing variation in fibre diameter along the staple, and of carrying more Merino sheep through winter on green annual pastures, with set stocking (SS) in 3 experiments. In experiments 1 and 2, SG involved grazing to a residual feed on offer (FOO) of 400 kg DM/ha with an estimated intake of about 0.8 kg DM/day for each sheep. Treatments commenced after pasture establishment in autumn–winter, with both treatments stocked at 20 wethers/ha until late spring. During spring, average liveweight changes were lower (P<0.01) under SG than SS (55 v. 153 g/day experiment 1; –16 v. 217 g/day experiment 2). Strip grazing, compared with SS, reduced (P<0.01) the variation in wool growth rate and fibre diameter along the staple leading to lower (P<0.01) clean wool weights (3.54 v. 3.94 and 2.97 v. 4.12 kg), but finer (P<0.01) (20.9 v. 22.0 and 19.5 v. 21.5 mm), stronger (P<0.01) (28.6 v. 25.3 and 39.9 v. 35.5 N/ktex) wool. However, there was also an increase in vegetable matter content of the wool. The effects on annual pastures were to increase grass (79 v. 48 and 59 v. 25%) and reduce legume (12 v. 36 and 22 v. 54%) content at the end of spring. In experiment 3, two strip grazing treatments were used: SGl with a residual FOO of about 400 kg DM/ha and a stocking rate of 28 wethers/ha; and SGh with a residual FOO of about 800 kg DM/ha and stocking rate of 14 wethers/ha. The stocking rate for SS was 12 wethers/ha. SGl, following an autumn deferment, enabled a stocking rate of 28 wethers/ha to be sustained through winter without supplementary feeding. This is substantially higher than the district average stocking rate of about 7 sheep/ha. Strip grazing reduced (P<0.01) liveweights at the completion of treatments (SGl 41.9 v. SGh 47.9 v. SS 60.3 kg), reduced (P<0.01) clean wool weights (3.40 v. 3.72 v. 4.54 kg) and mean fibre diameter (19.1 v. 19.0 v. 20.9 m), but increased staple strength (21.3 v. 19.0 v. 16.9 N/ktex). These results are discussed in relation to opportunities to utilise strip grazing in sheep production systems on annual pastures in south-western Australia.

scholarly journals Responses to selection for lean growth in sheep

2002 ◽  
Vol 74 (1) ◽  
pp. 39-50 ◽  
Author(s):  
G. Simm ◽  
R.M. Lewis ◽  
B. Grundy ◽  
W.S. Dingwall
Keyword(s):  
Fixed Effects ◽  
Mixed Model ◽  
Live Weight ◽  
Control Line ◽  
Breeding Values ◽  
Breeding Goal ◽  
Lean Growth ◽  
Selection For ◽  
Estimated Breeding Values ◽  
And Control

AbstractThis paper reports the selection responses achieved, and related results, following 9 years of index selection for lean growth in Suffolk sheep. The breeding goal of the index used comprised carcass lean weight and carcass fat weight at a constant age, with relative economic values of + 3 and –1 per kg. The selection criteria were live weight (LWT), ultrasonic fat depth (UFD) and ultrasonic muscle depth (UMD) adjusted to a constant age of 150 days. By year 9, responses in LWT, UFD and UMD in both sexes, as judged by the divergence between selection and control line performance, amounted to 4·88 kg, -1·1 mm and 2·8 mm respectively; these responses are between 7 and 15% of the overall means of the traits concerned. Although selection was originally on index scores based on phenotypic records, the retrospective analyses reported here used the mixed model applications of residual maximum likelihood to estimate parameters and best linear unbiased prediction to predict breeding values. The statistical model comprised fixed effects plus random effects accounting for direct additive, maternal additive and temporary environmental variation. Estimated genetic trends obtained by regressing estimated breeding values on year of birth were similar to annual responses estimated by comparing selection and control line means. Estimates of direct heritabilities were 0·054, 0·177, 0·286, 0·561 and 0·410 for birth weight (BWT), weaning weight (WWT), LWT, UFD and UMD respectively. Corresponding estimates of maternal heritabilities were 0·287, 0·205, 0·160, 0·083 and 0·164. Phenotypic correlations between all pairs of traits were positive and usually moderately high. There were low negative direct additive correlations between BWT and WWT, and between BWT and LWT, but higher positive maternal additive correlations between all other pairs of weight traits.

scholarly journals Merozoites of Theileria Orientalis Buffeli Reduce Parasitosis Following Challenge by Ticks Infested with T.Orientalis Ikeda

2020 ◽  
Author(s):  
David Emery ◽  
Susan de Burgh ◽  
Therese Hoang Hieu Hanh Dinh ◽  
Peter Rolls ◽  
Phillip Carter
Keyword(s):  
Field Experience ◽  
Carrier State ◽  
Clinical Disease ◽  
Haemaphysalis Longicornis ◽  
Bovine Blood ◽  
Theileria Orientalis ◽  
Associated Production ◽  
And Control ◽  
Production Losses

Abstract Background: An investigation aimed to confirm whether immunisation with the “benign” buffeli genotype of Theileria orientalis could reduce the parasitosis of the virulent ikeda genotype. Methods: Calves were inoculated intravenously or subcutaneously with bovine blood containing merozoites of T.orientalis buffeli. When recipients became positive, they and control animals were challenged with unfed nymphs of Haemaphysalis longicornis ticks infested as larvae with T.orientalis ikeda. Results: All calves became positive for the challenge within 12 days after tick application. In the immunised calves, the first wave of parasitosis with T.orientalis ikeda from 4-6 weeks was reduced significantly by >80% before the infestation declined into the carrier state by 9 weeks. Conclusions: The results confirm the field experience with theileriosis in endemic zones where the carrier state appears to prevent clinical disease despite repeated, seasonal tick infestations with virulent genotypes of the parasite. This method offers a means to reduce the severity of the first wave of theilerial parasitosis after tick challenge and recover associated production losses.

scholarly journals Genome-Wide Expression and Alternative Splicing in Domesticated Sunflowers (Helianthus annuus L.) under Flooding Stress

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 92
Author(s):  
Joon Seon Lee ◽  
Lexuan Gao ◽  
Laura Melissa Guzman ◽  
Loren H. Rieseberg
Keyword(s):  
Gene Expression ◽  
Alternative Splicing ◽  
Mixed Model ◽  
Agricultural Land ◽  
Alcohol Fermentation ◽  
Expression Levels ◽  
Flooding Stress ◽  
Genome Wide ◽  
And Control ◽  
Gene Expression Levels

Approximately 10% of agricultural land is subject to periodic flooding, which reduces the growth, survivorship, and yield of most crops, reinforcing the need to understand and enhance flooding resistance in our crops. Here, we generated RNA-Seq data from leaf and root tissue of domesticated sunflower to explore differences in gene expression and alternative splicing (AS) between a resistant and susceptible cultivar under both flooding and control conditions and at three time points. Using a combination of mixed model and gene co-expression analyses, we were able to separate general responses of sunflower to flooding stress from those that contribute to the greater tolerance of the resistant line. Both cultivars responded to flooding stress by upregulating expression levels of known submergence responsive genes, such as alcohol dehydrogenases, and slowing metabolism-related activities. Differential AS reinforced expression differences, with reduced AS frequencies typically observed for genes with upregulated expression. Significant differences were found between the genotypes, including earlier and stronger upregulation of the alcohol fermentation pathway and a more rapid return to pre-flooding gene expression levels in the resistant genotype. Our results show how changes in the timing of gene expression following both the induction of flooding and release from flooding stress contribute to increased flooding tolerance.

scholarly journals The impact of a ‘milking the COW’ campaign in a regional hospital in Singapore

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Surinder Kaur M. S. Pada ◽  
Poh Lishi ◽  
Kim Sim Ng ◽  
Sarathamani Rethenam ◽  
Lilibeth Silagan Alenton ◽  
...  
Keyword(s):  
Hand Hygiene ◽  
Pathogenic Bacteria ◽  
Mixed Model ◽  
Mixed Model Analysis ◽  
Colony Forming Units ◽  
Skin Flora ◽  
Before And After ◽  
The Difference ◽  
And Control ◽  
The Impact

Abstract Background Computerisation of various processes in hospitals and reliance on electronic devices raises the concern of contamination of these devices from the patient environment. We undertook this study to determine if an attached hand hygiene device that unlocks the screen of a computer on wheels (COW) on usage can be effective in decreasing the microbiological burden on computer keyboards. Methods An electronic hand sanitizer was integrated onto the COW. A prospective cohort study with a crossover design involving 2 control and 2 intervention wards was used. The study end point was the number of colony forming units found on the keyboards. Bacteria were classified into 4 main groups; pathogenic, skin flora, from the environment or those thought to be commensals in healthy individuals. We then used a mixed effects model for the statistical analysis to determine if there were any differences before and after the intervention. Results Thirty-nine keyboards were swabbed at baseline, day 7 and 14, with 234 keyboards cultured, colony forming units (CFUs) counted and organisms isolated. By mixed model analysis, the difference of mean bacteria count between intervention and control for week 1 was 32.74 (− 32.74, CI − 94.29 to 28.75, p = 0.29), for week 2 by 155.86 (− 155.86, CI − 227.45 to − 83.53, p < 0.0001), and after the 2-week period by 157.04 (− 157.04, CI − 231.53 to − 82.67, p < 0.0001). In the sub-analysis, there were significant differences of pathogenic bacteria counts for the Intervention as compared to the Control in contrast with commensal counts. Conclusion A hand hygiene device attached to a COW may be effective in decreasing the microbiological burden on computer keyboards.

A New Procedure of Production Orders Sequencing in Mixed-Model Production Systems

2014 ◽  
Vol 1036 ◽  
pp. 864-868 ◽  
Author(s):  
Marcin Zemczak ◽  
Damian Krenczyk
Keyword(s):  
Task Scheduling ◽  
Production System ◽  
Mixed Model ◽  
Production Systems ◽  
Production Capacity ◽  
Approximate Solutions ◽  
Task Sequence ◽  
Optimal Method ◽  
Sequencing Problem ◽  
Car Sequencing

The paper presents the task scheduling issue, which main aim is to establish a proper sequence of tasks, that would maximize the utilization of companys production capacity. According to the literature sources, the presented sequencing problem, denoted as CSP (Car Sequencing Problem) belongs to the NP-hard class, as has been proven by simple reduction from Hamiltonians Path problem. Optimal method of solution has not yet been found, only approximate solutions have been offered, especially from the range of evolutionary algorithms. Regardless of specific production system, while considering reception of new tasks into the system, current review of the state of the system is required in order to decide whether and when a new order can be accepted for execution. In this paper, the problem of task scheduling is limited to the specific existing mixed-model production system. The main goal is to determine the effective method of creation of task sequence. Through the use of computational algorithms, and automatic analysis of the resulting sequence, rates of production are able to be checked in a real time, and so improvements can be proposed and implemented.

Blockage Remediation in Deep Water Pipelines

2002 ◽  
Author(s):  
Ca´ssio Kuchpil ◽  
Marcelo A. L. Gonc¸alves ◽  
Antoˆnio C. P. Ferreira ◽  
Roberto S. Albernaz ◽  
Cla´udio S. Camerini ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Production Systems ◽  
Operational Conditions ◽  
Deep Waters ◽  
Water Pipelines ◽  
Pros And Cons ◽  
High Production ◽  
Organic Deposit ◽  
Production Losses ◽  
Exothermal Chemical

Flow assurance is an important issue in the design and operation of production systems in deep waters. The implementation of prevention and remediation methods is necessary mainly due to the low temperatures, high production pressures, long tie-ins and oils prone to organic deposit formation. Despite the development and improvement of these prevention and remediation techniques, failures or exceptional operational conditions can lead to the complete blockage of the submarine flowlines, risers or equipment. Although the complete blockage is not frequent, the related production losses generally are high; furthermore, the technical difficulties and the costs involved in the removal of blockages can be high. The steps to the remediation of subsea blockages are the localization, identification and removal methods. Due to the variety of problems, the different subsea layouts and surface facilities, it is not possible to have a general recipe for all problems. This paper presents some blockage remediation cases, including the localization and blockage remediation methods. The blockage localization methods used for the blockage removal cases described in this paper are the following: a) the echo of pressure pulses reflected at the blockage and b) a tool that detects the pipeline diameter variation with the pipeline pressure variations. The field results for these methods and the pros and cons of the methods are discussed. The remediation methods described are the following: external heating, internal intervention and exothermal chemical reaction using gravity.

Evaluation of a new technology when applied to sheep production systems: Part I—Model description

1989 ◽  
Vol 29 (1) ◽  
pp. 35-47 ◽  
Author(s):  
P.J. Bowman ◽  
D.A. Wysel ◽  
D.G. Fowler ◽  
D.H. White
Keyword(s):  
Production Systems ◽  
New Technology ◽  
Model Description ◽  
Sheep Production

scholarly journals Carcass and meat lamb and kid quality and development of consumer acceptability

2008 ◽  
Vol 37 (spe) ◽  
pp. 143-160 ◽  
Author(s):  
Carlos Sañudo Astiz
Keyword(s):  
Production Systems ◽  
Ageing Time ◽  
Small Ruminants ◽  
Consumer Acceptability ◽  
Meat Production ◽  
World Population ◽  
Local Market ◽  
Artificial Fibre ◽  
Human World ◽  
Sheep Production

Small ruminants have been one of the first domesticated species and from their origins have produced multiple benefits to humans. In the last two centuries, world sheep production has become more and more specialised upon geographical areas. But, recent changes in consumer attitudes, together with the increment in artificial fibre industries and human world population, some crisis related with the international wool market and some increments in lamb prices, have provoked that lamb meat has increased its relative importance inside the global sheep income. Also, sheep production systems vary considerably across the world, and reflect the different local environmental conditions, which determine, to a large extent, breeds, housing, levels of intensification and, at the end, local market requirements and qualities. However, among all the meats, sheep meat remains the most internationally traded (16 % of total world production is exported), which explains the potential existence of different lamb products in the same market. Then, the new requirements have created a higher interest for meat production, including its quality and quality marks. This interest from producers and the industry should be reflected in a proportional higher interest from the researches towards sheep and goat, where it exists, in general, important lacks of knowledge and, in particular, in lamb and kid meat Science. In the present speech we will made a special incidence on the relationship between carcass quality and lamb acceptability and on some factors like breed and species, diet and production system, slaughter weight and ageing time and their importance on the variation of the carcass and meat quality, including consumer acceptability.

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