18 results
The MeerKAT telescope as a pulsar facility: System verification and early science results from MeerTime
- M. Bailes, A. Jameson, F. Abbate, E. D. Barr, N. D. R. Bhat, L. Bondonneau, M. Burgay, S. J. Buchner, F. Camilo, D. J. Champion, I. Cognard, P. B. Demorest, P. C. C. Freire, T. Gautam, M. Geyer, J.-M. Griessmeier, L. Guillemot, H. Hu, F. Jankowski, S. Johnston, A. Karastergiou, R. Karuppusamy, D. Kaur, M. J. Keith, M. Kramer, J. van Leeuwen, M. E. Lower, Y. Maan, M. A. McLaughlin, B. W. Meyers, S. Osłowski, L. S. Oswald, A. Parthasarathy, T. Pennucci, B. Posselt, A. Possenti, S. M. Ransom, D. J. Reardon, A. Ridolfi, C. T. G. Schollar, M. Serylak, G. Shaifullah, M. Shamohammadi, R. M. Shannon, C. Sobey, X. Song, R. Spiewak, I. H. Stairs, B. W. Stappers, W. van Straten, A. Szary, G. Theureau, V. Venkatraman Krishnan, P. Weltevrede, N. Wex, T. D. Abbott, G. B. Adams, J. P. Burger, R. R. G. Gamatham, M. Gouws, D. M. Horn, B. Hugo, A. F. Joubert, J. R. Manley, K. McAlpine, S. S. Passmoor, A. Peens-Hough, Z. R Ramudzuli, A. Rust, S. Salie, L. C. Schwardt, R. Siebrits, G. Van Tonder, V. Van Tonder, M. G. Welz
-
- Journal:
- Publications of the Astronomical Society of Australia / Volume 37 / 2020
- Published online by Cambridge University Press:
- 15 July 2020, e028
-
- Article
-
- You have access Access
- HTML
- Export citation
-
We describe system verification tests and early science results from the pulsar processor (PTUSE) developed for the newly commissioned 64-dish SARAO MeerKAT radio telescope in South Africa. MeerKAT is a high-gain ( ${\sim}2.8\,\mbox{K Jy}^{-1}$ ) low-system temperature ( ${\sim}18\,\mbox{K at }20\,\mbox{cm}$ ) radio array that currently operates at 580–1 670 MHz and can produce tied-array beams suitable for pulsar observations. This paper presents results from the MeerTime Large Survey Project and commissioning tests with PTUSE. Highlights include observations of the double pulsar $\mbox{J}0737{-}3039\mbox{A}$ , pulse profiles from 34 millisecond pulsars (MSPs) from a single 2.5-h observation of the Globular cluster Terzan 5, the rotation measure of Ter5O, a 420-sigma giant pulse from the Large Magellanic Cloud pulsar PSR $\mbox{J}0540{-}6919$ , and nulling identified in the slow pulsar PSR J0633–2015. One of the key design specifications for MeerKAT was absolute timing errors of less than 5 ns using their novel precise time system. Our timing of two bright MSPs confirm that MeerKAT delivers exceptional timing. PSR $\mbox{J}2241{-}5236$ exhibits a jitter limit of $<4\,\mbox{ns h}^{-1}$ whilst timing of PSR $\mbox{J}1909{-}3744$ over almost 11 months yields an rms residual of 66 ns with only 4 min integrations. Our results confirm that the MeerKAT is an exceptional pulsar telescope. The array can be split into four separate sub-arrays to time over 1 000 pulsars per day and the future deployment of S-band (1 750–3 500 MHz) receivers will further enhance its capabilities.
LO36: Hyoscine butylbromide (Buscopan) for abdominal pain in children: a randomized controlled trial
- N. Poonai, S. Elsie, K. Kumar, K. Coriolano, S. Brahmbhatt, E. Dzongkowski, H. Stevens, P. Gupta, M. Miller, D. Ashok, G. Joubert, A. Butter, S. Ali
-
- Journal:
- Canadian Journal of Emergency Medicine / Volume 21 / Issue S1 / May 2019
- Published online by Cambridge University Press:
- 02 May 2019, p. S20
- Print publication:
- May 2019
-
- Article
-
- You have access Access
- Export citation
-
Introduction: Abdominal pain is one of the most frequent reasons for an emergency department (ED) visit. Most cases are functional and no therapy has proven effective. Our objective was to determine if hyoscine butylbromide (HBB) (BuscopanTM) is effective for children who present to the ED with functional abdominal pain. Methods: We conducted a randomized, blinded, superiority trial comparing HBB 10 mg plus acetaminophen placebo to oral acetaminophen 15 mg/kg (max 975 mg) plus HBB placebo using a double-dummy approach. We included children 8-17 years presenting to the ED at London Health Sciences Centre with colicky abdominal pain rated >40 mm on a 100 mm visual analog scale (VAS). The primary outcome was VAS pain score at 80 minutes post-administration. Secondary outcomes included adverse effects; caregiver satisfaction with pain management using a five-item Likert scale; recidivism and missed surgical diagnoses within 24-hours of discharge. Analysis was based on intention to treat. Results: We analyzed 225 participants (112 acetaminophen; 113 HBB). The mean (SD) age was 12.4 (3.0) years and 148/225 (65.8%) were females. Prior to enrollment, the median (IQR) duration of pain prior was 2 (4.5) hours and analgesia was provided to 101/225 (44.9%) of participants. The mean (SD) pre-intervention pain scores in the acetaminophen and HBB groups were 62.7 (15.9) mm and 60.3 (17.3) mm, respectively. At 80 minutes, the mean (SD) pain scores in the acetaminophen and HBB groups were 30.1 (28.8) mm and 29.4 (26.4) mm, respectively and there were no significant differences adjusting for pre-intervention scores (p = 0.96). The median (IQR) caregiver satisfaction was high in the acetaminophen [5 (2)] and HBB [5 (1)] groups (p = 0.79). The median (IQR) length of stay between acetaminophen [235 (101)] and HBB [234 (103)] was not significantly different (p = 0.53). The proportion of participants with a return visit for abdominal pain was 4/112 (3.5%) in the acetaminophen group and 6/113 (5.3%) in the HBB group. The most common adverse effect was nausea (9% in each group) and there were no significant differences in adverse effects between acetaminophen (26/112, 23.2%) and HBB (31/113, 27.4%) (p = 0.52). There were no missed surgical diagnoses. Conclusion: For children with presumed functional abdominal pain who present to the ED, both acetaminophen and HBB produce a clinically important (VAS < 30 mm) reduction in pain and should be routinely considered in this clinical setting.
LO25: How safe are our pediatric emergency departments? A multicentre, prospective cohort study
- A. Plint, L. Calder, Z. Cantor, M. Aglipay, A.S. Stang, A.S. Newton, S. Gouin, K. Boutis, G. Joubert, Q. Doan, A. Dixon, R. Porter, S. Sawyer, M. Bhatt, K. Farion, T. Crawford, D. Dalgleish, D.W. Johnson, T. Klassen, N. Barrowman, for Pediatric Emergency Research Canada
-
- Journal:
- Canadian Journal of Emergency Medicine / Volume 19 / Issue S1 / May 2017
- Published online by Cambridge University Press:
- 15 May 2017, p. S36
- Print publication:
- May 2017
-
- Article
-
- You have access Access
- Export citation
-
Introduction: Data regarding adverse events (AEs) (unintended harm to the patient from health care provided) among children seen in the emergency department (ED) are scarce despite the high risk setting and population. The objective of our study was to estimate the risk and type of AEs, and their preventability and severity, among children treated in pediatric EDs. Methods: Our prospective cohort study enrolled children <18 years of age presenting for care during 21 randomized 8 hr-shifts at 9 pediatric EDs from Nov 2014 to October 2015. Exclusion criteria included unavailability for follow-up or insurmountable language barrier. RAs collected demographic, medical history, ED course, and systems level data. At day 7, 14, and 21 a RA administered a structured telephone interview to all patients to identify flagged outcomes (e.g. repeat ED visits, worsening/new symptoms, etc). A validated trigger tool was used to screen admitted patients’ health records. For any patients with a flagged outcome or trigger, 3 ED physicians independently determined if an AE occurred. Primary outcome was the proportion of patients with an AE related to ED care within 3 weeks of their ED visit. Results: We enrolled 6377 (72.0%) of 8855 eligible patients; 545 (8.5%) were lost to follow-up. Median age was 4.4 years (range 3 months to 17.9 yrs). Eight hundred and seventy seven (13.8%) were triaged as CTAS 1 or 2, 2638 (41.4%) as CTAS 3, and 2839 (44.7%) as CTAS 4 or 5. Top entrance complaints were fever (11.2%) and cough (8.8%). Flagged outcomes/triggers were identified for 2047 (32.1%) patients. While 252 (4.0%) patients suffered at least one AE within 3 weeks of ED visit, 163 (2.6%) suffered an AE related to ED care. In total, patients suffered 286 AEs, most (67.9%) being preventable. The most common AE types were management issues (32.5%) and procedural complications (21.9%). The need for a medical intervention (33.9%) and another ED visit (33.9%) were the most frequent clinical consequences. In univariate analysis, older age, chronic conditions, hospital admission, initial location in high acuity area of the ED, having >1 ED MD or a consultant involved in care, (all p<0.001) and longer length of stay (p<0.01) were associated with AEs. Conclusion: While our multicentre study found a lower risk of AEs among pediatric ED patients than reported among pediatric inpatients and adult ED patients, a high proportion of these AEs were preventable.
MP005: Treating and Reducing Anxiety and Pain PEDs (TRAPPED 2): time for action - a PERC project
- E. D. Trottier, S. Ali, G. Meckler, M. Blachet, A.S. Stang, R. Porter, S. Le May, A. Dubrovsky, M. Chan, R. Jain, T. Principi, G. Joubert, A.J. Kam, J. Thull-Freedman, G. Neto, M. Lagacé, J. Gravel
-
- Journal:
- Canadian Journal of Emergency Medicine / Volume 18 / Issue S1 / May 2016
- Published online by Cambridge University Press:
- 02 June 2016, pp. S67-S68
- Print publication:
- May 2016
-
- Article
-
- You have access Access
- Export citation
-
Introduction: Multiples barriers to appropriate analgesia are reported in the paediatric emergency department (PED), including limited accessibility to effective strategies. Our objective: was to evaluate the improvement in the accessibility of pain and anxiety management strategies in Canadian PEDs, after the creation of a national pediatric pain Quality Improvement Collaborative (QIC), through Pediatric Emergency Research Canada (PERC). Methods: In 2013, the TRAPPED 1 survey was administered to Canadian PEDs, in order to evaluate what resources were in place for pain and anxiety management. A pain QIC was then created to stimulate the implementation of new strategies, through information sharing between PEDs. In 2015, the TRAPPED 2 cross sectional survey was administered. Its focus was to evaluate the improvement in the accessibility of specific strategies reported by each centre, after participating in this QIC, and working to implement change within their own PEDs. Results: All 15/15 Canadian PEDs responded to the TRAPPED 1 survey in 2013 and 11 agreed to participate in the national pain QIC. In-person, phone meetings, follow up surveys and email communications were employed for information sharing. Strategies identified by the QIC to be newly introduced in individual centres were educational initiatives, distraction options, nurse-initiated protocols and intranasal (IN) medications. All 15 PEDs completed the TRAPPED 2 survey. Compared to 2013, an increased number of PEDs used face-based pain scales (14/15 vs 6/15) and behavioural scales (5/15 vs 1/15) for pain assessment in 2015. Use of reminder posters on pain management at triage increased from 4/15 to 6/15 PEDs. Availability of tablets for distraction increased from 4/15 to 10/15 PEDs. Nurse-initiated protocols for topical anesthetic and oral sucrose (for needle procedures) increased from 10/15 to 12/15 sites and from 12/15 to 14/15 sites respectively. Availability of IN medications increased; fentanyl from 9/15 to 14/15 sites and midazolam from 8/15 to 10/15 sites. Ten of the 11 PEDs involved in the QIC strategy reported the implementation of at least one of their own identified strategies. Conclusion: This study suggests that the use of a QIC may improve the introduction of new strategies to reduce pain and anxiety in EDs. QICs may also be helpful to other centres when introducing new strategies.
Contributors
-
- By Maged Argalious, Craig Beattie, Bruce Biccard, John Carlisle, Rod T. A. Chalmers, Michael F. M. James, Ivan A. Joubert, Danny McGee, Carl Moores, Gary A. Morrison, Charles Morton, Alastair F. Nimmo, Suzy O' Neill, Chris P. Snowden, Mark D. Stoneham, Michael Swart, Richard Telford, Alastair J. Thomson, John A. Wilson
- Edited by Carl Moores, Alastair F. Nimmo
-
- Book:
- Core Topics in Vascular Anaesthesia
- Published online:
- 05 July 2012
- Print publication:
- 07 June 2012, pp vi-vi
-
- Chapter
- Export citation
A study of pre-natal growth and development in the sheep
- D. M. Joubert
-
- Journal:
- The Journal of Agricultural Science / Volume 47 / Issue 4 / August 1956
- Published online by Cambridge University Press:
- 27 March 2009, pp. 382-428
-
- Article
- Export citation
-
1. The results are presented of an investigation in which the growth and development of forty single male sheep foetuses was examined. The material, obtained from slaughterhouses, included seventeen specimens of known age, while further details of the remainder were lacking. For these reasons, and the fact that the specimens were preserved in 10% formalin prior to dissection, relative, rather than absolute, trends were discussed. This had been achieved by expressing all values as percentages of those obtained from four single male lambs dissected at birth.
2. In order to age the experimental material with the greatest possible accuracy, data were collected from the literature on foetal weights and crownrump lengths of specimens of known age. Mean values were computed and normographs established for the pre-natal period between 18 days and fullterm. By employing the method of least squares, it was not possible to fit single curves to the data; in the case of both weight and crown-rump length the curves had to be divided into five segments in order to establish the relationships with age. Apart from a rather marked change in the rate of growth and development between the 109th and 110th days of gestation, the apparent ‘breaks’ in the curves were not considered important. It would seem that lack of data at certain stages, together with the heterogeneity of the population studied, were greatly responsible for the differential rates of growth and development recorded.
3. The data were inadequate to examine fully the effect of fixation on foetal weight; however, it would appear that whereas specimens weighing less than 200 g. and over 1200 g. lost weight during the course of preservation, foetuses intermediate between the above values gained weight. Since the causes could not be satisfactorily explained, the need for further investigation was emphasized.
4. Of the foetal measurements recorded, head length and, particularly, head width were shown to be earlier maturing than chest circumference and chest depth, while crown-rump length made even greater proportional increases during pre-natal life. In general, the results supported accepted theory that the retardation of rate of development proceeds in an anterior-posterior direction prior to birth.
5. By dissecting the head from the body and weighing each unit separately, it was shown that the head decreases in relative size throughout foetal life. Head:body ratio, however, was found to be unsuitable as a criterion of pre-natal age, since foetuses of equal age may differ appreciably in this respect. It was shown, for example, that a lamb at birth, though above the average in terms of absolute weight, may possess the conformation of a 120-day-old foetus on the basis of head: body ratio.
6. Dissections of the major constituent parts of the foetal body indicated the skinned head to be the earliest maturing, followed in order by the organs (weighed en masse), dressed carcass, total skin and, finally, the skinned feet and tail, which were latest maturing. The order in which these parts grow before birth appeared explicable primarily upon a basis of functional necessity.
7. The skull was shown to develop to a relatively lesser degree during foetal life than the mandibles, while skull measurements indicated the cranial portion to be earlier maturing than the facial. Linear measurements of the various vertebral regions at different stages of development did not yield entirely satisfactory results, but it was evident that the anterior cervical vertebrae are earlier maturing than those of the posterior extremity (caudal vertebrae).
8. Weights of the major units of both thoracic and pelvic limbs indicated the former to be slightly earlier maturing. In contrast to the direction of retardation of growth during post-natal life, in the foetus the gradient followed a proximo-distal direction; scapula and pelvis, for example, being earlier maturing than metacarpus and metatarsus.
9. Linear development of individual bones was shown to be earlier maturing than growth in weight. However, on the basis of length measurements, the course of development proceeded in a similar direction as the trends established in terms of weight, i.e. proximo-distally. Width of pelvis, on the contrary, was shown to be earlier maturing than width of scapula; this was explained in terms, particularly, of earlier developing cartilage in the former bone.
10. In terms of weight, m. longissimus dorsi appeared to be earlier maturing than m. rectus femoris and m. gastrocnemius lateralis; between the latter two muscles no marked difference in rate of growth could be established. The results indicated that these three muscles develop at much the same rate in respect of length and depth during pre-natal life, but m. longissimus dorsi showed relatively less development in width over the same period of time than the other muscles.
11. Of each of the above-mentioned muscles, the cross-diameter of fifty individual fibres was measured by means of an ocular micrometer. Again, a tendency was observed for fibres of m. longissimus dorsi to be earlier maturing than those of m. rectus femoris or m. gastrocnemius.
12. Development of muscle-fibre diameter during foetal life was examined further on the overall mean for the three muscles studied, i.e. the mean of 150 measurements per foetus. The results showed that whereas muscle-fibre diameter increased but slightly (approximately 19·5%) during the first two-thirds of pre-natal life, the increase thereafter was substantial; on the basis of a linear regression, the increase amounted to 113·2% from about 108 days to full-term. The data thus appears to support the accepted view that muscular growth occurs initially by an increase in the number of fibres, and in late foetal life primarily by hypertrophy.
13. The dispersion of muscle-fibre sizes, in absolute measure, was shown to increase with advancing foetal age, the range at birth being considerable. In accord with the results of other investigators, a small proportion of small fibres was observed between approximate ages of 61 and 68 days which, apparently, were not present at either earlier or later stages.
14. Measurement of fibres from muscles situated in different anatomical regions of the body indicated that the muscles of the head were earlier maturing than those of the trunk, and muscles of the thoracic limb earlier maturing than those of the pelvic limb. In agreement with the results obtained on bone weights and measurements, the retardation appeared to proceed in a proximo-distal direction, particularly in the case of the pelvic limb.
Relation between body size and muscle fibre diameter in the newborn lamb
- D. M. Joubert
-
- Journal:
- The Journal of Agricultural Science / Volume 47 / Issue 4 / August 1956
- Published online by Cambridge University Press:
- 27 March 2009, pp. 449-455
-
- Article
- Export citation
-
1. An investigation is reported in which the relationship was examined between body size and muscle fibre size of nineteen newborn lambs and including twelve males and seven females. Body size was measured in terms of the dead body weight and that of the dressed carcass, while muscle fibre size was estimated on the basis of the mean crossdiameter of 150 fibres per lamb.
2. It was shown that the dressing (or carcass) percentage tends to increase with an increase in body weight, from 42·26% at a body weight of 2000 g. to 49·04% at 7000 g.
3. Of the 2850 cross-diameters recorded, the majority (33·8%) of the fibres measured between 8·0 and 9·6 μ, while individual fibres varied in size from 1·6 to 22·4 μ.
4. Highly significant, positive correlations were shown to exist between both body (r = 0·996) and carcass (r = 0·946) weight, and mean muscle fibre diameter, indicating that differences in size between the lambs may be accounted for largely by corresponding variations in the size of individual muscle fibres.
5. Of the three muscles sampled m. gastrocnemius had the largest mean fibre diameter (10·38μ), followed in decreasing order by m. rectus femoris (9·72 μ) and m. longissimus dorsi (9·09 μ). These inter-muscle differences were significant at the 1% level of probability.
6. Ram lambs had significantly thicker muscle fibres (10·32 μ) than ewe lambs (8·72 μ), but also weighed the heavier and produced heavier dressed carcasses. Some evidence was produced, however, in support of the theory that at comparable weights males possess thinner individual, and therefore a greater number of fibres than females.
The influence of winter nutritional depressions on the growth, reproduction and production of cattle
- D. M. Joubert
-
- Journal:
- The Journal of Agricultural Science / Volume 44 / Issue 1 / February 1954
- Published online by Cambridge University Press:
- 27 March 2009, pp. 5-66
-
- Article
- Export citation
-
1. During the period May 1948 to May 1952, a study was made of the influence of seasonal fluctuations in the nutritive value of the natural pastures in the Bankenveld region of the Transvaal, on the growth, reproduction and production of cattle. The paired method of investigation was adopted, each heifer maintained on grazing alone having a related counterpart of the same age which received supplementary feeding during the winter months. The former treatment was termed ‘Low plane’, and the latter referred to as the ‘High plane’. Four breeds were included in the investigation, viz. Friesians and Jerseys, and Shorthorns and Afrikaners, thus representative of both dairy and beef types. The latter breed also represented the stock indigenous to South Africa. Initially five pairs per breed were studied, but deaths and other causes depleted the numbers to twenty-eight head after 4 years of investigation.
2. Since the investigation formed part of a series of studies which have been in progress at the University of Pretoria and Agricultural Research Institute during the past two decades, the results of which hitherto remained unpublished, a review is provided in the early chapters. To furnish some indication of the natural conditions ruling in the Bankenveld region, the agro-ecological background is discussed, particular attention being paid to physical and nutritional factors. It is shown that for at least 6 months of the year the climate tends to be subtropical, whilst the results of digestion trials on pasture samples, indicated serious nutritional depressions in the natural grazing during winter.
The influence of high and low nutritional planes on the oestrous cycle and conception rate of heifers
- D. M. Joubert
-
- Journal:
- The Journal of Agricultural Science / Volume 45 / Issue 2 / December 1954
- Published online by Cambridge University Press:
- 27 March 2009, pp. 164-172
-
- Article
- Export citation
-
1. During the course of investigations on the influence of High- and Low-nutritional planes on the growth, reproduction and production of heifers, sexual activity was studied by recording oestrus data. A total of 239 observations were recorded for fourteen maiden heifers for each nutritional plane; 161 for the High-plane individuals and 78 for those on the Low plane. The investigation included four breeds, viz. Beef Shorthorn, Afrikaner, Friesian and Jersey.
2. The average length of the dioestrous cycle was 20·16 days for the High-plane animals, and 20·83 days for their Low-plane counterparts, the difference of 0·67 days not being statistically significant. Breed differences were not very marked, but a tendency was revealed for the Friesians of both planes to have slightly longer cycles on an average than any other breed studied.
3. The modal length of the cycle for both groups was found to be 19 days, with 95·6% of the cycles falling within the normal range of 17 to 23 days. Cycles exceeding 33 days in length were, however, excluded from these calculations.
4. A tendency was revealed for the initial postpubertal cycles to be longer on an average than what is usually considered the normal length. Although the High-plane heifers settled down to a regular rhythm sooner, observations showed that differences existing between individual animals is probably of greater significance in this regard than any other factor.
5. Whereas the majority of the High-plane heifers reached puberty during winter, 85·7% of the Lowplane heifers came on heat for the first time in summer. It is suggested that with the approach of favourable nutritional conditions, animals in a low condition first restore depleted body tissues before the sexual cycle returns to normal activity.
6. A slight tendency was noticed for cycle length to vary with the season in the case of the High-plane animals, longer cycles being recorded in summer than in winter. On the Low plane, however, the heifers concerned invariably experienced an anoestrous condition during winter, lasting anything up to 218 days. Only after they regained the losses in live weight, was sexual activity restored as previously pointed out.
7. Sexual activity was shown to be greatest in late summer with little variation over the remainder of the year under normal conditions of nutrition and management, while in the Low-plane individuals it fluctuated from complete inactivity in midwinter to a peak in summer.
8. Post-partum oestrus was considerably delayed by lactation in the beef animals. The High plane heifers came on heat only after weaning their calves while the Low-plane individuals required nearly a year in addition to regain depleted body reserves before sexual activity was restored. The Low-plane dairy heifers showed a longer post-partum anoestrous period also, the difference between the two groups being 20·77 days.
9. The results for the number of services required per conception demonstrated that the Low-nutritional plane caused no detrimental influence on this factor. In fact, the difference existing between the two groups studied was in favour of the Low plane animals. This is in agreement with Asdell's (1952) findings. It was shown that season had no effect on the results obtained.
A crossbreeding experiment with cattle, with special reference to the maternal effect in South Devon—Dexter crosses
- D. M. Joubert, John Hammond
-
- Journal:
- The Journal of Agricultural Science / Volume 51 / Issue 3 / December 1958
- Published online by Cambridge University Press:
- 27 March 2009, pp. 325-341
-
- Article
- Export citation
-
An investigation was carried out to determine the extent of the maternal influence on size of calves at birth and during subsequent stages of growth, by making reciprocal matings between large South Devon and small Dexter cattle. As a preliminary to the experimental results, data concerning the respective parent breeds were analysed. From the first part of the study the following information was obtained:
1. The mean weight at birth of purebred South Devon calves was 100·3 ± 1·47 lb. with a tendency, though not statistically significant, for male calves to be heavier. Calves born during the months April to July appeared to be heavier than those born at other times, but the age of the dam had no definite effect on the birth weight of offspring. It was found, however, that the sire may influence birth weight to a significant degree.
2. The mean period of pregnancy for South Devon females, carrying purebred foetuses, was 287·0 ± 0·42 days, the tendency being for males to be carried longer, but the difference of 0·97 days was not statistically significant. A statistically significant difference indicated that winter calvers carry their foetuses longer as a rule, but though heifers have shorter gestation periods than cows, the difference of 1·6 days was not significant.
An analysis of factors influencing post-natal growth and development of the muscle fibre
- D. M. Joubert
-
- Journal:
- The Journal of Agricultural Science / Volume 47 / Issue 1 / February 1956
- Published online by Cambridge University Press:
- 27 March 2009, pp. 59-102
-
- Article
- Export citation
-
1. An investigation is described in which the effect of both technical and physiological factors on muscle fibre size was examined. Size was determined by measuring the cross-diameter of 16,450 individual fibres by means of an ocular micrometer. In cases where an animal was represented by a single muscle sample, 100 fibres were measured, otherwise fifty measurements were recorded per sample.
2. The material consisted of muscle samples always taken from the same position along the length of the muscle and immediately afterwards fixed for varying periods of time in 10% formalin. Samples were obtained from various sources, principally from experiments conducted in the past at the School of Agriculture, Cambridge, but also from slaughterhouses and contemporary investigations. These latter samples were treated in the same manner to ensure consistency.
3. From the results of an investigation on the effect of formalin fixation on muscle fibre diameter, carried out on samples obtained from a mature buck rabbit, it was tentatively concluded that although shrinkage does occur the effect is only slight; the difference between measurements of fresh compared with fixed fibres being non-significant statistically. Shrinkage apparently ceased as soon as the fixative had penetrated the sample, since no further changes could be detected after prolonged fixation.
4. The same material was used to study the effect of heat. Application of heat (boiling) for a matter of seconds caused an immediate, highly significant, shrinkage.of individual fibres, but continued heattreatment resulted in no further changes. Though heat caused the fibre to lose its characteristic striated appearance, there were no signs of fibres disintegrating or of the sarcolemma becoming detached from its protoplasmic contents.
5. From the results of previous investigations it was deduced that the measurement of 100 fibres per sample provides a reliable mean value and a representative indication of the dispersion in a given muscle, or at a given age. Results obtained in the present study demonstrated a slight tendency for larger fibres to be measured as the period of observation proceeds, a factor which should be guarded against.
6. The effect of species on muscle fibre diameter was examined by comparing fibres of m. gastrocnemius of the rabbit, the pig, the sheep and cattle at birth and maturity. Only male animals were included in the comparison. It was shown that no relation exists between muscle fibre size and body size at either age. At birth the rabbit and sheep had rather similar-sized fibres, while those of the pig and cattle were respectively smaller and larger in diameter. At maturity the pig had the largest fibres, followed in decreasing order by the rabbit, cattle and sheep. The size of muscle fibres at maturity was accounted for by the degree of post-natal development in body weight of the particular species.
7. The effect of breed was studied on two groups of steers, the one consisting of Dairy Shorthorns and Dairy Shorthorn-crosses, and the other of Friesians and Friesian-crosses. Samples were available from m. longissimus dorsi for each of thirty-four animals: 100 fibres were measured per sample. The Friesians and their crosses had significantly thicker muscle fibres than the pure- and cross-bred Dairy Shorthorn steers. The largest differences existed between the respective pure-bred animals; differences between Friesian × Angus and Dairy Shorthorn × Angus, and Friesian × Hereford and Dairy Shorthorn × Hereford, though fairly distinct, were, however, not statistically significant.
8. The effect of age was investigated on a group of forty-one lambs of different nutritional status and sex, and ranging in age from birth to 290 days. Muscle fibre diameter was shown to increase in general with age, while a consistent decline in the coefficient of variation was regarded as indicative of the fact that muscular growth during post-natal life occurs essentially by hypertrophy of individual fibres, there being no increase in the number of fibres after birth.
9. Correlating changes in muscle fibre diameter with corresponding changes in weight, indicated that muscular growth is primarily a function of physiological age, and not strictly one of chronological age. Though highly significant correlations were established between mean fibre diameter and body and carcass weights, the strongest correlation was shown to exist between the former variate and muscle weight. However, a correlation of an even higher order was obtained between the square of muscle fibre diameter and muscle weight. It was attempted, by means of linear regressions, to indicate the contribution of length growth of the fibres to increments in muscle weight. The need for further investigation is, however, apparent; insufficient data in the present study made it impossible to elucidate this point altogether.
The relationships were confirmed by an analysis of twenty lambs of the same breed, all slaughtered at 112 days of age; the heavier lambs had larger fibres than their lighter counterparts, very nearly proportional to differences in weight of muscle.
10. Sex differences in muscle fibre diameter could very nearly be accounted for on a basis of muscle weight alone at birth and at a carcass weight of 13·6 kg. At 290 days of age, high-plane wethers had but slightly thicker fibres than their female counterparts, despite a significantly heavier musculature. This was ascribed to differences in length of muscle (as shown by bone measurements), and also to differences in composition of the muscle. The results of chemical analyses were presented to prove that the muscles of wethers at that age contain greater amounts of intra-muscular (chemical) fat, hence the apparent increases in the weight of muscle could not be accounted for by an increase in the diameter of component fibres.
11. The effect of nutrition was studied in both lambs and mature ewes and shown to influence muscle fibre diameter appreciably at all ages. However, at birth the differences, though in favour of the high-plane lambs, were not significant statistically, probably due to small numbers in the respective groups. Muscle fibre diameter of mature ewes on a supermaintenance diet increased in proportion to increases in total muscle, while on a submaintenance diet the opposite effect was found. It appeared that continuation of the supermaintenance treatment would have resulted in but little additional changes in the diameter of fibres, while prolongation of the submaintenance treatment probably would have caused considerable further shrinkage of individual fibres.
12. The effect of the individual muscle was studied by comparing absolute and relative development of fibres of m. longissimus dorsi, m. rectus femoris and m. gastrocnemius. At birth m. gastrocnemius possessed the largest fibres and m. longissimus dorsi the smallest. On the whole, fibres of m. longissimus dorsi, the muscle being situated in a late maturing part of the body, showed greatest relative increases during post-natal life, while those of m. gastrocnemius, an earlier maturing muscle, increased latest. On an average, m. rectus femoris had larger fibres than m. longissimus dorsi at maturity, those of m. gastrocnemius being the smallest in absolute measure. Comparing the relative degree to which different muscles develop under high and low planes of nutrition, muscle fibre measurements indicated that the low-plane animals at a chronological age of 290 days, resembled their 60-day-old high-plane counterparts in anatomical development.
In mature animals, the early maturing gastrocnemius appeared to benefit most initially from a supermaintenance diet; however, during the later stages of the experiment, m. longissimus dorsi fibres showed the greatest relative increases, followed in order by m. rectus femoris and m. gastrocnemius. On the submaintenance ration, m. longissimus dorsi fibres appeared to be reduced in size at a greater rate initially than those of the other muscles. Individual variation, however, made it extremely difficult to generalize during subsequent stages.
13. From width and depth measurements on m. longissimus dorsi (or ‘eye muscle’) recorded at the junction of the thoracic and lumbar vertebrae, it was shown that width is the earlier maturing dimension and less affected by nutritional factors than depth.
Though significant relationships were found between mean fibre diameter and both muscle width and depth, the latter dimension was the more strongly correlated with changes in thickness of fibres.
14. It has been suggested that work of this nature might provide a suitable basis for estimating the amount of muscular tissue in a carcass; such a relationship would be of great assistance to students of meat physiology who have to resort to laborious dissection techniques for data on carcass composition. It is obvious, however, that factors such as species, breed, and possibly sex, would have to be considered in an attempt to establish a relationship of this kind. Furthermore, the effect of the individual muscle used for test would demand consideration, different muscles being influenced to varying degrees by age and nutrition. A late maturing muscle probably would furnish the most reliable criterion; in the light of evidence produced by this study, m. longissimus dorsi sampled at the junction of the lumbar and thoracic regions has been suggested as most suitable.
A score card for lamb and mutton carcasses
- J. S. Starke, D. M. Joubert
-
- Journal:
- The Journal of Agricultural Science / Volume 57 / Issue 3 / November 1961
- Published online by Cambridge University Press:
- 27 March 2009, pp. 319-323
-
- Article
- Export citation
-
A score card is suggested for the judging of lamb and mutton carcasses. To apply the score card, measurements have to be recorded on length of leg (F), circumference of buttock (D), width (A) and depth (B) of ‘eye muscle’ (m. longissimus dorsi) and depth of back fat (C) and rib fat (J). In addition, visual judgement is required of fat covering on leg (E), marbling (G) and texture and colour of eye muscle (H). Points are deducted beyond an optimum weight which differs for lamb and mutton carcasses respectively.
A note on the effect of docking on fat deposition in fat-tailed sheep
- D. M. Joubert, L. Ueckermann
-
- Journal:
- Animal Production / Volume 13 / Issue 1 / February 1971
- Published online by Cambridge University Press:
- 02 September 2010, pp. 191-192
- Print publication:
- February 1971
-
- Article
- Export citation
-
The deposition of body and subcutaneous fat was compared in two groups of fat-tailed sheep, the one group docked shortly after birth and the tails of the other left intact. The slightly heavier live and carcass weights of the latter animals could be accounted for almost entirely by their significantly heavier weights of caudal fat, there being no firm evidence in support of increased internal or subcutaneous fatty deposition following amputation of the cauda.
The maternal effects on size at birth and weaning in Landrace-Native pig crosses
- D. M. Joubert
-
- Journal:
- Animal Production / Volume 4 / Issue 1 / February 1962
- Published online by Cambridge University Press:
- 01 February 1962, pp. 117-121
- Print publication:
- February 1962
-
- Article
- Export citation
-
Reciprocal matings between large, improved Swedish Landrace and small, primitive South African Native pigs produced strong evidence of a maternal effect at birth. However, compared with purebred Landrace piglets, the crossbred offspring out of large dams weighed less; conversely, compared with purebred Native piglets, the crossbred offspring out of small dams were heavier at birth. Differences between the various mean weights were all statistically significant.
At weaning (eight weeks of age), the weights of crossbred pigs out of large Landrace sows equalled those of purebred Landrace pigs. Crossbred pigs out of Native-pig sows occupied an intermediate position between the above-mentioned and purebred Native pigs. The differences between the latter group means remained significant statistically.
Effect of age at which lambs are castrated on carcass weight and quality
- D. M. Joubert
-
- Journal:
- Animal Production / Volume 1 / Issue 2 / September 1959
- Published online by Cambridge University Press:
- 01 September 1959, pp. 163-165
- Print publication:
- September 1959
-
- Article
- Export citation
-
Groups of Dorper lambs were castrated at three ages: shortly after birth, and at two and four months of age. All were slaughtered at an age of six months and the carcasses subsequently weighed, graded, measured and scored. The results indicate no marked differences in either weight or quality of carcass between the treatments. It is concluded that the operation can safely be carried out, depending upon circumstances, at any stage between birth and four months.
On the effect of breed and nutritional plane on dentition in the cow
- D. M. Joubert
-
- Journal:
- Proceedings of the British Society of Animal Production / Volume 1956 / 1956
- Published online by Cambridge University Press:
- 06 May 2016, pp. 111-116
- Print publication:
- 1956
-
- Article
- Export citation
-
A Number of authors (Bonsma and Neser, 1951; Bisschop, 1954; Wiener and Donald, 1955) have recently provided experimental evidence on the age at which the eruption of permanent incisors occurs in cattle and, in view of the wide ranges generally encountered, criticised the practice of estimating age from dental development. Though factors such as individuality, breed, plane of nutrition and type of grazing are frequently quoted as being responsible for deviations from the ‘accepted’ means (Miller and Robertson, 1952; Zorn, 1953), apparently little support is to be found in the scientific literature on the subject.
On the Post-Natal Growth and Development of Muscle in Relation to Quality in Meat
- D. M. Joubert
-
- Journal:
- Proceedings of the British Society of Animal Production / Volume 1954 / 1954
- Published online by Cambridge University Press:
- 06 May 2016, pp. 49-58
- Print publication:
- 1954
-
- Article
- Export citation
-
Dividing the meat carcass into its three main component tissues, bone, muscle and fat, it is known that they develop in a well-defined order, bone being the earliest maturing and fat the latest (Hammond, 1932). Of the three, muscle is the most important from the viewpoint of human nutrition and the factors influencing its growth obviously demand serious consideration. The literature on qualitative growth contains numerous references to microscopical meat studies, but, due to the diversity of conditions under which the observations were made, the results obtained cannot easily be co-ordinated. An investigation was therefore planned in which most of the major factors influencing growth and development of muscle in general, and the muscle fibre in particular, could be studied.
Sanitary Convention Between the United States and Other Powers.1: Signed at Washington, October l4, 1905; Ratified, May 29, 1906; Proclaimed, March 1, 1909
- D. Eduardo Moore, Juan J. Ulloa, Juan Guiteras, E. B. Barnet, Emilio C. Joubert, M. H. Alcivar, Walter Wyman, H. D. Geddings, John S. Fulton, Walter D. McCaw, J. D. Gatewood, H. L. E. Johnson, Joaquín Yela, E. Licéaga, J. L. Medina, Daniel Edo Lavorería, N. Veloz Goiticoa
-
- Journal:
- American Journal of International Law / Volume 3 / Issue S3 / July 1909
- Published online by Cambridge University Press:
- 04 May 2017, pp. 237-251
- Print publication:
- July 1909
-
- Article
- Export citation