Six years of selection responses for resistance or susceptibility to ryegrass staggers in sheep

1999 ◽  
Vol 7 ◽  
pp. 27-31
Author(s):  
C.A. Morris ◽  
N.R. Towers ◽  
N.C. Amyes
Keyword(s):  
Genetic Parameters ◽  
Phase 1 ◽  
Breeding Value ◽  
Selection Line ◽  
Phase 2 ◽  
Genetic Studies ◽  
Lolium Perenne L ◽  
Susceptible Line ◽  
Ewe Lambs ◽  
Selection For

Ryegrass staggers (RGS) is a neurotoxic disease in ruminants. It is caused by the mycotoxin lolitrem B, found in endophyte-infected perennial ryegrass (Lolium perenne L.). This paper reviews genetic studies on the resistance of sheep to RGS at Ruakura. Genetic differences in susceptibility among sire groups were evaluated in lambs born in 1988-92 (Phase 1). Selection lines were then formed and responses to selection for resistance or susceptibility are described for the 1993-98 birth years (Phase 2). The incidence of RGS was recorded on a presence or absence basis from January to March or April each year, in experimental flocks with animals of known pedigree. For estimating genetic parameters (Phase 1), there were 3587 RGS records available from 2307 animals representing 232 sires. Clinical cases of RGS occurred in 17 of 25 contemporary groups, with incidences per group up to 16%. Estimates of heritability and acrossyear repeatability for RGS incidence were 0.068 ± 0.028 and 0.24 ± 0.05 respectively. Breeding value data were used at the beginning of Phase 2 to screen ewes, two-tooths and ewe lambs into resistant and susceptible selection flocks (lines). Breeding values were also used to select rams that were elite for RGS, and to allocate these to each line for mating. At least some natural RGS challenge was experienced by the resulting selection-line stock born in five of the six years of Phase 2. Susceptible-line lambs had a mean incidence of 39% clinical RGS cases over these five years, whilst the resistant-line lambs grazing the same paddocks had a much lower mean clinical RGS incidence (P

scholarly journals Influence of feeding differentiation on the age at onset of puberty in Brazilian Bergamasca dairy ewe lambs

2016 ◽  
Vol 68 (1) ◽  
pp. 22-28 ◽  
Author(s):  
A. Dantas ◽  
E.R. Siqueira ◽  
S. Fernandes ◽  
E. Oba ◽  
A.M. Castilho ◽  
...  
Keyword(s):  
Body Condition Score ◽  
Phase 1 ◽  
Average Daily Gain ◽  
Age At Onset ◽  
Phase 2 ◽  
Plasma Growth Hormone ◽  
Ewe Lambs ◽  
Condition Score ◽  
Puberty Onset ◽  
Daily Gain

The objective of the study was to evaluate body growth and age at onset of puberty on lambs fed two specific diets for low and high growth rates. A herd of 20 Brazilian Bergamasca lambs was divided in two groups (n= 10) and kept confined throughout the experimental period, two animals of the same treatment/pen. Two phases were established: Phase 1, from 90 days of age until the onset of puberty; and Phase 2, from puberty onset up to 1 year old. For Phase 1, two distinct diets were formulated, being: Treatment A, which was formulated to obtain an average daily gain of approximately 150g; and Treatment B, for an average daily gain of about 250g. In Phase 2, a balanced, equal diet was provided to both groups. Every 14 days, the animals were weighed and given average daily gain, average daily dry matter intake and body condition score. From the 5th month of age on, in each group, a vasectomized male was used to detect estrus, establishing age at puberty onset and estrus interval for each lamb. Blood samples were collected every 28 days to determine plasma growth hormone concentration. Treatment B lambs gained more weight and had higher body condition score (P<0.05) and there was no difference for age at puberty onset and plasma growth hormone levels (P>0.05) between treatments. It was found that both treatments showed satisfactory performances. Thus, treatment A may be indicated as a reasonable feeding system to achieve positive responses on confined ewe lambs during growth phase.

Plane of nutrition of Corriedale ewe lambs from foetal life to the onset of breeding affects weight at service and reproductive outcome

2015 ◽  
Vol 55 (8) ◽  
pp. 1011
Author(s):  
L. Piaggio ◽  
H. Deschenaux ◽  
F. Baldi ◽  
S. Fierro ◽  
G. Quintans ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Soybean Meal ◽  
Phase 1 ◽  
Breeding Period ◽  
Phase 2 ◽  
Phase 3 ◽  
Ewe Lambs ◽  
Native Pastures ◽  
New Treatments ◽  
First Year Of Life

The objective of this study was to identify periods in the life (foetal and postnatal) of Corriedale ewe lambs where different nutrition levels can affect bodyweight at breeding and pregnancy rate in their first year of life. The effect of three different phases of nutrition on the growth and pregnancy rate (n = 133) of Corriedale ewe lambs of 7 months of age were evaluated. Phase 1 included the last phase of gestation of their mothers (30 last days of gestation, Day –30; partum = Day 0) until marking (Day 24). Phase 2 was between marking and weaning (Day 114) and phase 3 between weaning to the onset of breeding (Day 207). For phase 1, 350 adult ewes had access to improved pastures (phase 1, H) or native pastures (phase 1, L). After lambing, all ewes and their lambs were offered native pastures. After marking only ewes bearing females lambs were kept. In phase 2, 67 lambs born to H and 66 lambs born to L ewes were sorted in two new treatments: access to native pastures supplemented with ~1% of their bodyweight with soybean meal (phase 2, H) or access to native pastures alone (phase 2, L). In phase 3, each of the lambs of the four treatments applied during phase 2 were sorted in two new treatments: access to improved pastures (phase 3, H) or native pastures supplemented with 0.7% of liveweight with soybean meal (phase 3, L). Breeding period lasted 41 days and pregnancy diagnosis was performed 86 days after the onset of breeding. The pregnancy rate varied from 0% to 47%. Phase 3 of nutrition was the only phase that affected pregnancy rate (28% vs. 10% for female lambs offered H and L plane of nutrition respectively; P = 0.005). A discriminative analysis demonstrated that the liveweight at breeding was the only variable that affected the success of pregnancy in ewe lambs (P = 0.0025). Moreover, the ewe lambs that were heavier at the onset of breeding (more than 35 kg or in average 38 kg) were the most successful to get pregnant (35% of pregnancy for lambs over 35 kg and 13% for lambs under 35 kg, P = 0.0044). In conclusion, under the conditions of this experiment, the most important parameters to explain successful pregnancy of ewe lambs were the growth rate after weaning, and the liveweight at the onset of breeding.

scholarly journals Canadian Collaborative Project on Genetic Susceptibility to MS, Phase 2: Rationale and Method

1998 ◽  
Vol 25 (3) ◽  
pp. 216-221 ◽  
Author(s):  
A.D. Sadovnick ◽  
N.J. Risch ◽  
G.C. Ebers ◽  
Keyword(s):  
Genetic Susceptibility ◽  
Familial Aggregation ◽  
Phase 1 ◽  
Molecular Genetic ◽  
Genetic Research ◽  
Population Based ◽  
Phase 2 ◽  
Genetic Studies ◽  
Collaborative Project ◽  
Index Cases

ABSTRACT:Background:Results from the Canadian Collaborative Project on Genetic Susceptibility to Multiple Sclerosis (MS)-Phase 1 (CCPGSMS-Phase 1) together with other family data published since 1982 have led to the following conclusions about the etiology of MS: (i) genetic and non-genetic (environmental) factors are involved in the etiology of MS on a population basis; (ii) the familial aggregation of MS is genetic; (iii) maternal factors do not influence the risk for siblings to develop MS; and (iv) MS appears to be oligogenic. The present paper describes the rationale and methodology for the CCPGSMS-Phase 2.Methods:The CCPGSMS-Phase 2 is a nation-wide collaborative effort involving all the 15 Canadian MS clinics. A series of structured questionnaires is administered to MS index cases, spouse controls and mothers of index cases and spouse controls (if available) by trained interviewers. Blood samples are taken for molecular genetic studies. This national effort is coordinated by the MS Clinics in Vancouver and London.Results:The CCPGSMS-Phase 2 is in progress so specific results are not available. The study is designed to (i) increase the database for genetic epidemiological/molecular genetic research and (ii) gather population-based data to further our understanding of the non-genetic factors in the etiology of MS.Conclusions:It is anticipated that the results from this study will impact on the eventual prevention, cure and treatment of MS.

scholarly journals Mammary artery Doppler ultrasonography of Brazilian Bergamasca dairy ewe lambs under the influence of two different feeding plans

2017 ◽  
Vol 37 (2) ◽  
pp. 179-182
Author(s):  
Ariane Dantas ◽  
Edson R. Siqueira ◽  
Simone Fernandes ◽  
Eunice Oba ◽  
Vânia M.V. Machado ◽  
...  
Keyword(s):  
Body Condition ◽  
Body Condition Score ◽  
Phase 1 ◽  
Mammary Tissue ◽  
Phase 2 ◽  
Ewe Lambs ◽  
Body Development ◽  
Condition Score ◽  
Hemodynamic Characteristics ◽  
Two Phases

ABSTRACT: Blood supply of mammary gland is extremely important, since it is a crucial factor in the mammary tissue development. The objective of this study was to describe and assess main mammary artery hemodynamic characteristics of lambs with two growth rates, using Doppler ultrasound. Two experimental groups, A and B, (n=10) of female Brazilian Bergamasca lambs were kept under the same management conditions and facilities. There were two phases: Phase 1, from 90 days of age until onset of puberty; Phase 2, from puberty until 1 year of age. During phase 1, a specific diet was formulated to each experimental group to obtain two different average daily gains: 150g, for treatment A, and 250g, for treatment B. During phase 2, there was no difference on the diet offered to both groups. Every 14 days, all animals were weighed and their body condition score was evaluated. Every 60 days, ultrasound exams (Doppler) of mammary artery were performed to obtain resistance and pulsatility indexes. Treatment B lambs showed higher weight gain and higher body condition score (P<0.05). However, for resistance and pulsatility indexes, there was no difference between treatments (P>0.05). Hemodynamic values remained constant, independent of diet or body development presented by the animals. Obtained data is valuable information on Bergamasca ewe lambs development.

scholarly journals Genomic Analysis of Purebred and Crossbred Angus Cows Quantifies Heterozygosity, Breed, and Additive Effects on Components of Reproduction

Animals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 61
Author(s):  
Wayne S. Pitchford ◽  
Judith M. Pitchford ◽  
Jena G. Alexopoulos ◽  
Michelle L. Hebart
Keyword(s):  
Reproductive Performance ◽  
Genetic Parameters ◽  
Genomic Analysis ◽  
Reproductive Traits ◽  
Breeding Value ◽  
Additive Effects ◽  
Breed Differences ◽  
Maternal Performance ◽  
Selection For ◽  
Angus Heifers

Multiple studies have quantified the production differences of Hereford Angus crossbreds compared to purebred Angus for a range of traits including growth, carcass, and reproductive traits. This study aims to quantify breed and heterosis effects on maternal performance using genomics. Thirty Hereford and thirty Angus sires were mated to 1100 Angus heifers and cows in a large commercial herd run on pasture at Musselroe Bay, Tasmania, Australia. Approximately 1650 calves were born. Heifers were weaned, scanned for attainment of puberty prior to joining at approximately 15 months of age, joined, and then recorded for status of pregnancy, calving, lactating, 2nd pregnancy, and weaning of second calf. Heterozygosity effects were significant for heifer pre-joining weight and height as well as proportion pubertal. Breed differences were significant for the same traits plus pregnancy rate at second joining and proportion rearing two calves. Genetic parameters were reported for 13 traits. On average, higher genetic merit (Estimated Breeding Value, EBV percentile) Hereford bulls were used than Angus for growth and puberty, but they were similar for fat and reproduction. Days to calving BREEDPLAN EBVs of the sires were related to puberty and reproduction. Scrotal size BREEDPLAN EBVs of the sires were related to attainment of puberty genomic EBVs calculated. In summary, breed differences in growth and puberty were due to heterosis, but there was an advantage of Hereford genes for reproductive performance. Ongoing emphasis on selection for reduced days to calving and estimation of multi-breed EBVs is important.

Maternal productivity of Angus cows divergently selected for post-weaning residual feed intake

2005 ◽  
Vol 45 (8) ◽  
pp. 985 ◽  
Author(s):  
P. F. Arthur ◽  
R. M. Herd ◽  
J. F. Wilkins ◽  
J. A. Archer
Keyword(s):  
Milk Yield ◽  
Feed Intake ◽  
Subcutaneous Fat ◽  
Residual Feed Intake ◽  
Divergent Selection ◽  
Breeding Value ◽  
Selection Line ◽  
Selection For ◽  
Estimated Breeding Value ◽  
In Pregnancy

Data on 185 Angus cows were used to study the effect of divergent selection for residual feed intake on maternal productivity across 3 mating seasons, starting from 2000. The cows were the result of 1 to 2.5 generations of selection (mean of 1.5), and differed in estimated breeding value for residual feed intake by 0.8 kg/day. In general, cows lost subcutaneous fat (measured 2 times a year) during the period when they were nursing calves, and gained fat thereafter. No significant selection line differences in fatness were observed except for those measured at the start of the 2000 (10.8 ± 0.4 v. 9.3 ± 0.4 mm), 2001 (11.3 ± 0.4 v. 9.8 ± 0.4 mm) and 2002 (7.0 ± 0.5 v. 5.7 ± 0.5 mm) mating seasons, where high residual feed intake cows had significantly (P<0.05) higher rib fat depths. No significant selection line differences in weight (measured 4 times a year) were observed. However, the cows either maintained or lost weight during the calf nursing period, and gained weight thereafter, with mean weights ranging from 450 to 658 kg. There were no significant selection line differences in pregnancy (mean 90.4%), calving (mean 88.7%) and weaning (mean of 80.8%) rates, milk yield (mean 7.7 kg/day) and weight of calf weaned per cow exposed to bull (mean 195 kg). The study indicates that after 1.5 generations of divergent selection for residual feed intake there are no significant selection line differences for maternal productivity traits.

Rationalization and internalization

2001 ◽  
Vol 60 (4) ◽  
pp. 215-230 ◽  
Author(s):  
Jean-Léon Beauvois
Keyword(s):  
Phase 1 ◽  
Facilitatory Effect ◽  
Phase 2 ◽  
Causal Explanations ◽  
Reduction Effect ◽  
Dissonance Reduction

After having been told they were free to accept or refuse, pupils aged 6–7 and 10–11 (tested individually) were led to agree to taste a soup that looked disgusting (phase 1: initial counter-motivational obligation). Before tasting the soup, they had to state what they thought about it. A week later, they were asked whether they wanted to try out some new needles that had supposedly been invented to make vaccinations less painful. Agreement or refusal to try was noted, along with the size of the needle chosen in case of agreement (phase 2: act generalization). The main findings included (1) a strong dissonance reduction effect in phase 1, especially for the younger children (rationalization), (2) a generalization effect in phase 2 (foot-in-the-door effect), and (3) a facilitatory effect on generalization of internal causal explanations about the initial agreement. The results are discussed in relation to the distinction between rationalization and internalization.

PENERAPAN MODEL QUANTUM LEARNING UNTUK MENINGKATKAN HASIL BELAJAR AUTOCAD SISWA KELAS X TEKNIK PEMESINAN SMK NEGERI 1 STABAT

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Abdul Hasan Saragih
Keyword(s):  
Positive Response ◽  
Phase 1 ◽  
First Grade ◽  
Learning Model ◽  
Second Phase ◽  
Phase 2 ◽  
Phase 3 ◽  
The Third ◽  
Third Phase ◽  
Quantum Learning

This classroom research was conducted on the autocad instructions to the first grade of mechinary class of SMK Negeri 1 Stabat aiming at : (1) improving the student’ archievementon autocad instructional to the student of mechinary architecture class of SMK Negeri 1 Stabat, (2) applying Quantum Learning Model to the students of mechinary class of SMK Negeri 1 Stabat, arising the positive response to autocad subject by applying Quantum Learning Model of the students of mechinary class of SMK Negeri 1 Stabat. The result shows that (1) by applying quantum learning model, the students’ achievement improves significantly. The improvement ofthe achievement of the 34 students is very satisfactory; on the first phase, 27 students passed (70.59%), 10 students failed (29.41%). On the second phase 27 students (79.41%) passed and 7 students (20.59%) failed. On the third phase 30 students (88.24%) passed and 4 students (11.76%) failed. The application of quantum learning model in SMK Negeri 1 Stabat proved satisfying. This was visible from the activeness of the students from phase 1 to 3. The activeness average of the students was 74.31% on phase 1,81.35% on phase 2, and 83.63% on phase 3. (3) The application of the quantum learning model on teaching autocad was very positively welcome by the students of mechinary class of SMK Negeri 1 Stabat. On phase 1 the improvement was 81.53% . It improved to 86.15% on phase 3. Therefore, The improvement ofstudent’ response can be categorized good.

In situ deteriorating patient simulation in general practice

2020 ◽  
Vol 70 (suppl 1) ◽  
pp. bjgp20X711425
Author(s):  
Joanna Lawrence ◽  
Petronelle Eastwick-Field ◽  
Anne Maloney ◽  
Helen Higham
Keyword(s):  
Life Support ◽  
Early Recognition ◽  
Phase 1 ◽  
Patient Simulation ◽  
Medical Emergency ◽  
Phase 2 ◽  
Action Plans ◽  
Integrated Simulation ◽  
Deteriorating Patient

BackgroundGP practices have limited access to medical emergency training and basic life support is often taught out of context as a skills-based event.AimTo develop and evaluate a whole team integrated simulation-based education, to enhance learning, change behaviours and provide safer care.MethodPhase 1: 10 practices piloted a 3-hour programme delivering 40 minutes BLS and AED skills and 2-hour deteriorating patient simulation. Three scenarios where developed: adult chest pain, child anaphylaxis and baby bronchiolitis. An adult simulation patient and relative were used and a child and baby manikin. Two facilitators trained in coaching and debriefing used the 3D debriefing model. Phase 2: 12 new practices undertook identical training derived from Phase 1, with pre- and post-course questionnaires. Teams were scored on: team working, communication, early recognition and systematic approach. The team developed action plans derived from their learning to inform future response. Ten of the 12 practices from Phase 2 received an emergency drill within 6 months of the original session. Three to four members of the whole team integrated training, attended the drill, but were unaware of the nature of the scenario before. Scoring was repeated and action plans were revisited to determine behaviour changes.ResultsEvery emergency drill demonstrated improved scoring in skills and behaviour.ConclusionA combination of: in situ GP simulation, appropriately qualified facilitators in simulation and debriefing, and action plans developed by the whole team suggests safer care for patients experiencing a medical emergency.

Clinical Drug Development for the Treatment of Pulmonary Arterial Hypertension: Collaboration With the Pharmaceutical Industry and Regulatory Agencies

2010 ◽  
Vol 9 (4) ◽  
pp. 214-219
Author(s):  
Robyn J. Barst
Keyword(s):  
Clinical Trials ◽  
Pulmonary Arterial Hypertension ◽  
Drug Development ◽  
Phase 1 ◽  
Preclinical Studies ◽  
Phase 2 ◽  
Phase 3 ◽  
Preclinical Testing ◽  
New Drug ◽  
Pulmonary Arterial

Drug development is the entire process of introducing a new drug to the market. It involves drug discovery, screening, preclinical testing, an Investigational New Drug (IND) application in the US or a Clinical Trial Application (CTA) in the EU, phase 1–3 clinical trials, a New Drug Application (NDA), Food and Drug Administration (FDA) review and approval, and postapproval studies required for continuing safety evaluation. Preclinical testing assesses safety and biologic activity, phase 1 determines safety and dosage, phase 2 evaluates efficacy and side effects, and phase 3 confirms efficacy and monitors adverse effects in a larger number of patients. Postapproval studies provide additional postmarketing data. On average, it takes 15 years from preclinical studies to regulatory approval by the FDA: about 3.5–6.5 years for preclinical, 1–1.5 years for phase 1, 2 years for phase 2, 3–3.5 years for phase 3, and 1.5–2.5 years for filing the NDA and completing the FDA review process. Of approximately 5000 compounds evaluated in preclinical studies, about 5 compounds enter clinical trials, and 1 compound is approved (Tufts Center for the Study of Drug Development, 2011). Most drug development programs include approximately 35–40 phase 1 studies, 15 phase 2 studies, and 3–5 pivotal trials with more than 5000 patients enrolled. Thus, to produce safe and effective drugs in a regulated environment is a highly complex process. Against this backdrop, what is the best way to develop drugs for pulmonary arterial hypertension (PAH), an orphan disease often rapidly fatal within several years of diagnosis and in which spontaneous regression does not occur?

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