Growth modeling of dairy heifers in Québec based on random regression

Cue, R. I., Pietersma, D., Lefebvre, D., Lacroix, R., Wade, K., Pellerin, D., de Passillé, A-M. and Rushen, J. 2012. Growth modeling of dairy heifers in Québec based on random regression. Can. J. Anim. Sci. 92: 33–47. A total of 144 006 weight (calculated from tape girth measurements) and height data records from Québec dairy heifers were analyzed using random regression to estimate growth curve parameters of Ayrshires, Brown Swiss and Holstein animals to permit prediction of individual heifer growth from 0 to 32 mo. There were, on average, 5.15 records per heifer (minimum 3 records, maximum 25 records). The body weight data were analyzed using linear and quadratic fixed and random regressions, with a power-of-the-mean (POM) function to model the residual variance. The POM was 1.2 for Holstein and Ayrshire and slightly less than 1 for Brown Swiss. Estimated body weight at 24 mo was 507, 564, 624 kg, for Ayrshires, Brown Swiss and Holstein, respectively. The height data were analyzed with a Brody, monomolecular non-linear growth curve model. Mature height was estimated to be 148 cm in both Holstein and Ayrshires, and 150 cm in Brown Swiss. Random regression models were shown to be able to predict individual growth, and can be incorporated in decision-support tools to help producers reducing the average age at first calving.

[Scientific research in family medicine: practitioners' experience, barriers and needs]

Scientific data from family medicine are relevant for the majority of the population. They are therefore essential from an ethical and public health perspective. We need to promote quality research in family medicine despite methodological, financial and logistic barriers. To highlight the strengths and weaknesses of research in family medicine in the French-speaking part of Switzerland we asked practitioners from this region to share their experience, critics and needs in relation to research. This article summarizes their contribution in light of the international literature.

An advisory tool to improve management practices affecting calf and heifer welfare on dairy farms

We developed an advisory tool addressing 10 critical areas of calf and heifer management, including calving management, care to newborn calves and painful procedures, colostrum management, cow-calf separation, calf feeding, weaning, calf housing, heifer feeding, heifer housing, and general monitoring. Targets and indicators for each critical area were validated by a panel of experts and maximum scores were assigned based on experts' opinions and reviews of scientific literature. The tool was tested on 28 Quebec dairy farms for feasibility and repeatability between 2 observers. Farmers were asked to test colostrum quality, measure blood IgG concentrations, and record health events. The on-farm evaluation included an interview on management practices and an evaluation of conditions in the barn. Scorings and recommendations were discussed with producers. The usefulness of our on-farm welfare tool was evaluated by the producers themselves during a final debriefing. We reached the main goals of a successful advisory tool of calf and heifer management to improve welfare on dairy farms. We respected the targeted time limit of a 3-h visit covering all aspects of our tool including data collection on management and environment, scoring, practical demonstration with producers, and debriefing. We had no problems collecting management- and environment-based data and had high repeatability of qualitative environment-based measures (kappa value>0.6). Our tool helped to detect problems and to discuss these problems with the producers; producers scored below 50% for some targets in calving management, care to newborn calves and painful procedures, colostrum management, and calf feeding. The targets were realistic so producers were not discouraged. All producers were convinced of the usefulness of our tool for identifying areas of calf and heifer management in need of improvement. They were also convinced of the usefulness of our tool as an advisory tool for technical advisors and veterinarians. Six months after the on-farm visit, recommended practices were implemented in many of these areas. Voluntary improvements in animal welfare can be facilitated by using appropriate tools to educate producers and help them change their attitudes toward calf management and animal welfare.

A survey of dairy calf management practices in Canada that affect animal welfare

There is growing interest among the public in farm animal welfare and a need for methods to assess animal welfare on farm. A survey on calf rearing practices that might affect dairy calf welfare was performed via a 1-h interview on 115 dairy farms (mean +/- SD: herd size=52.5+/-20.9 cows; milk production=8,697+/-1,153L) distributed throughout the province of Quebec. Despite frequent recommendations, many dairy producers continue to use management practices that increase the health risks of milk-fed calves. Major risk factors for poor calf welfare identified were 1) no use of calving pen in 51.3% of herds and low level of surveillance of calvings, especially at nighttime (once every 12h), 2) no disinfection of newborn's navel in 36.8% of herds, and delayed identification and, hence, calf monitoring (3 d), 3) 15.6% of farms relied on the dam to provide colostrum and none checked colostrum quality or passive transfer of immunity, 4) dehorning and removal of extra teats proceeded at late ages (6.4 wk and 6.7 mo, respectively) and without adequate pain control, 5) use of traditional restrictive milk feeding and waste milk distributed to unweaned calves without precaution in 48.2% of herds, 6) abrupt weaning performed in 16.5% of herds, and 7) calves housed individually in 87.9% of herds, and most inappropriate housing systems (crate=27.0%, tie-stall=13.9%, attached against a wall=5.7%) remained. This risk factor assessment was the first step in an intervention strategy to improve calf welfare on dairy farms.

An anaphylactic reaction to transdermal delivered fentanyl

Immediate allergic hypersensitivity reactions with fentanyl are rarely reported. We diagnosed a presumably IgE-mediated allergic hypersensitivity reaction comprising generalized erythema and bronchospasm 4 h after the first-time application of transdermal fentanyl. Prick test remained negative with fentanyl whereas an intradermal test (IDT) with fentanyl was positive (dilution 10(-2)). Cross-reactivity was found with sufentanil but not with remifentanil. The diagnosis was supported by the clinical history and a positive IDT with fentanyl. This case report confirms the need for a systematic allergological investigation in case of immediate hypersensitivity reactions for all drugs and all modes of administration.

Assessment of determinants for osteoporosis in elderly men

SUMMARY

The aim of this cross-sectional study was to determine and quantify some determinants associated to low bone mineral density (BMD) in elderly men. This study showed that ageing, a lower body mass index (BMI), a higher blood level of C-terminal cross-linking telopeptides of type I collagen (CTX-1), family history of osteoporosis, and/or fracture and prior fracture were associated with bone mineral density.

INTRODUCTION

Our aims were to identify some determinants associated to low bone mineral density in men and to develop a simple algorithm to predict osteoporosis.

METHODS

A sample of 1,004 men aged 60 years and older was recruited. Biometrical, serological, clinical, and lifestyle determinants were collected. Univariate, multivariate, and logistic regression analyses were performed. Receiver operating characteristic analysis was used to assess the discriminant performance of the algorithm.

RESULTS

In the multiple regression analysis, only age, BMI, CTX-1, and family history of osteoporosis and/or fracture were able to predict the femoral neck T-score. When running the procedure with the total hip T-score, prior fracture also appeared to be significant. With the lumbar spine T-score, only age, BMI, and CTX-1 were retained. The best algorithm was based on age, BMI, family history, and CTX-1. A cut-off point of 0.25 yielded a sensibility of 78%, a specificity of 59% with an area under the curve of 0.73 in the development and validation cohorts.

CONCLUSION

Ageing, a lower BMI, higher CTX-1, family history, and prior fracture were associated with T-score. Our algorithm is a simple approach to identify men at risk for osteoporosis.

Protein extraction from activated sludge: an analytical approach

To investigate the efficiency of different methods on exopolymeric substance (EPS) extraction, mechanical and chemical treatments were applied on two activated sludges, regarding the yield of protein extraction as well as their compatibility with usual quantification methods. Mechanical disruption methods do not drastically affect protein measurements by both bicinchoninic acid (BCA) and modified Lowry methods. Chemical compounds such as cationic exchange resin and triton show high interference with modified Lowry method while the protein quantification by BCA method is not affected. In addition, inner sludge compounds were shown to interfere with both methods: BCA and modified Lowry measurement respectively overestimate and underestimate protein content. According to these data, BCA method was chosen in this study as the most appropriate protein quantification method in sludge extracts. Comparison of various extraction protocols, combining mechanical and/or chemical treatments, shows that efficiency can be increased by repeating the same method or by applying a prior mechanical treatment. Proteins are preferably extracted by triton treatments, indicating the importance of hydrophobic interactions linking proteins to the EPS matrix. The amount of extracted proteins reaches 182 and 148 mg eq.BSA g(-1)VSS using triton/triton and ultraturax/triton extractions, respectively. Protease activity/extracted protein ratios vary widely depending on extraction protocols. Protease seemed to be preferably extracted by ultrasound and triton treatments (150-220 U mg(-1)protein). This study underlines that the choice of a relevant coupled quantification/extraction method is of great importance for efficient EPS determination.

Fuzzy multimodel of timed Petri nets

This paper deals with discrete event systems (DES) modeled either by discrete timed Petri nets without conflict or by continuous Petri nets. A fuzzy rule-based multimodel is developed for this kind of system. The behavior of each Petri net transition is described by the combination of two linear local fuzzy models. Using the Takagi-Sugemo model in a systematic way, we define the exact modeling for both classes of timed Petri nets. As a result, we notice that classical sets result in the exact description of discrete timed Petri nets. On the contrary, only fuzzy sets are suitable to describe continuous Petri nets exactly. The proposed fuzzy multimodels are very interesting from a control point of view. In that sense, general results such as convergence for timed Petri nets are given.

The European Convention for the Protection of Pet Animals and tail docking in dogs

The European Convention for the Protection of Pet Animals was opened for signature in Strasbourg on 13 November 1987 and entered into force on 1 May 1992. This Convention states that: 'Surgical operations for the purpose of modifying the appearance of a pet animal or for other non-curative purposes shall be prohibited and, in particular: the docking of tails'. At present, 15 of the 27 States in the European Union have ratified this Convention (with or without reserving their position on tail docking) and have prohibited cosmetic surgical operations. In addition, four European States have prohibited these operations, even though they did not ratify the Convention. These policy positions agree with both the current knowledge on tail amputations in dogs and the opinions of official veterinary associations in Europe and North America.

Effect of a porcine circovirus type 2 infection on embryos during early pregnancy

The aim of the present study was to assess the effects of porcine circovirus type 2 (PCV2) on porcine embryos and their receptor sows during the first 21 days of pregnancy. Hatched blastocysts exposed to 10(5.0) TCID50 PCV2 per ml (strain 1121, fifth passage PK15) and negative control embryos were transferred to PCV2-immune receptor sows at the 7th day of the cycle. Two weeks after transfer (D21), the receptor sows were euthanized and embryos were recovered. They were assessed macroscopically for viability and examined for viral antigen-positive cells by immunoperoxidase staining. The embryonic survival rate of the PCV2-exposed embryos (6.4%, 7 viable embryos out of 110 transferred) was significantly lower than the survival rate of the negative control embryos (65.4%, 34 viable embryos out of 52 transferred). All of the non-viable PCV2-exposed embryos (n=9) displayed immunohistochemical positive signals for PCV2-antigen in degenerated tissues. In the PCV2-exposed embryos that were categorized as viable at D21, small clusters (n=4) or no PCV2-positive cells (n=3) were detected. The pregnancy results of the receptor sows that received PCV2-exposed embryos (1/5) were considerably different from the negative control receptors (2/2), with 3 out of 5 sows displaying a regular return to oestrus. In conclusion, it can be stated that PCV2 can replicate in embryos and might lead to embryonic death. In a small proportion of embryos, PCV2 exposure does not have a detrimental effect on embryo development before D21.

Trends in growth and age at first calving for Holstein and Ayrshire heifers in Quebec

The objective was to provide an overview of heifer growth in Quebec and analyze its relationship with age at first calving. Heifer body weights, wither heights, body condition scores, and breeding events collected from 1993 to 2003 were obtained and combined with first lactation data, mature body weights, type classification final score and frame/capacity, and estimated breeding values for milk, conformation, frame/capacity, and Lifetime Profit Index. Analyses were restricted to 39 animal-level variables. The resulting data set consisted of 44 989 Holsteins and 2294 Ayrshires with data available for at least one variable. The average age at first calving was 26.5 and 27.1 mo for Holsteins and Ayrshires, respectively. For Holsteins, average daily gains in body weights were 0.79, 0.89, 0.87, and 0.70 kg d-1 for 0 to 4 mo (birth to weaning), 4 to 10 mo (to target onset of puberty), 10 to 14 mo (to first breeding), and 14 mo to pre-calving periods of growth, respectively. Body weights at 14 mo, conception, and post calving were 398, 464, and 601 kg, respectively, and relative to mature body weight were 59, 68 and 89%, respectively. Correlations with age at first calving, corrected for herd and year of birth effects, were positive for body weight at conception (0.69), body weight at first calving (0.31), and number of breedings (0.37), and negative for the average daily gain from conception to post calving (-0.38) and body weight at 14 mo relative to mature body weight (-0.20). For Ayrshires, body weights and average daily gains were lower than for Holsteins, but body weights relative to mature body weight and correlations were generally similar. Holsteins and Ayrshires calved substantially earlier and at a heavier body weight compared with Quebec data from the 1980s. The results of this study suggest that heifer growth may not be a limiting factor in reducing the average age at first calving in Québec. Key words: Dairy cattle, field-recorded data, heifer, growth

Correlation between the presence of neutralizing antibodies against porcine circovirus 2 (PCV2) and protection against replication of the virus and development of PCV2-associated disease

Background

In a previous study, it was demonstrated that high replication of Porcine circovirus 2 (PCV2) in a gnotobiotic pig was correlated with the absence of PCV2-neutralizing antibodies. The aim of the present study was to investigate if this correlation could also be found in SPF pigs in which PMWS was experimentally reproduced and in naturally PMWS-affected pigs.

Results

When looking at the total anti-PCV2 antibody titres, PMWS-affected and healthy animals seroconverted at the same time point, and titres in PMWS-affected animals were only slightly lower compared to those in healthy animals. In healthy animals, the evolution of PCV2-neutralizing antibodies coincided with that of total antibodies. In PMWS-affected animals, neutralizing antibodies could either not be found (sera from field studies) or were detected in low titres between 7 and 14 DPI only (sera from experimentally inoculated SPF pigs). Differences were also found in the evolution of specific antibody isotypes titres against PCV2. In healthy pigs, IgM antibodies persisted until the end of the study, whereas in PMWS-affected pigs they quickly decreased or remained present at low titres. The mean titres of other antibody isotypes (IgG1, IgG2 and IgA), were slightly lower in PMWS-affected pigs compared to their healthy group mates at the end of each study.

Conclusion

This study describes important differences in the development of the humoral immune response between pigs that get subclinically infected with PCV2 and pigs that experience a high level of PCV2-replication which in 3 of 4 experiments led to the development of PMWS. These observations may contribute to a better understanding of the pathogenesis of a PCV2-infection.

Organic matter release in low temperature thermal treatment of biological sludge for reduction of excess sludge production

Thermal treatment applied in association with a biological system allows for a significant reduction in excess sludge production (approximately 50%). In general, heat treatment is described as a sludge disintegration technique. This paper offers a thorough study on the impact of heat treatment, at temperatures below 100 degrees C, on the solubilisation of the sludge COD and its biodegradability. Discontinuous heating experiments were performed on activated and digested sludge. At all temperatures tested the released COD for digested sludge was systematically higher than that for activated sludge (15 and 40%, respectively, at 95 degrees C for 40 min of contact time). For the first 30 min, a 1st order kinetic, with respect to the residual COD, was systematically found. In the range of 40-95 degrees C, digested sludge had a lower activation energy than activated sludge (26 kcal/mol compared to 70-160 kcal/mol). COD solubilisation is thus more positively influenced by temperature in the case of activated sludge. This may be due to the significant difference in the ratio of protein/carbohydrate in digested and activated sludge (1-5 and 0.2-0.7, respectively). The increase in the COD/TKN ratio in the solubilised fraction after thermal treatment of activated sludge suggests a preferential solubilisation of proteins over carbohydrates. Respirometric tests performed on the solubilised COD showed that whatever the sludge origin, only 40-50% of released COD is biodegradable at a conventional hydraulic retention time (i.e., 24 h). Hence, heat treatment would act more through organic matter solubilisation rather than by a biodegradability increase.

[From blind knowledge to experiential knowledge]

A postgraduate course in psychosomatic and psychosocial medicine for general practitioners started in 1999 from Marc Archinard advice. It consists of about half the hours required for the "Attestation de formation complémentaire" granted by the Swiss Academy of psychosomatic and psychosocial medicine (AMPP). This article describes the elaboration of a questionnaire assessing the professional competences acquired by the practitioners after the course. As practitioners they valorise knowledge coming from their experiences on patient relationships and group exchanges, own maturational process, delegation process as well as expansion of therapeutic choices.

Extended Lower Limb Venous Ultrasound for the Diagnosis of Proximal and Distal Vein Thrombosis in Asymptomatic Patients after Total Hip Replacement

OBJECTIVE

To assess the performance of extended lower limb venous ultrasound (US) for the diagnosis of asymptomatic deep vein thrombosis (DVT) and to estimate a 3-month DVT incidence on repeated US after total hip replacement.

DESIGN

Diagnostic performance study and prospective cohort study.

MATERIALS AND METHODS

US was compared to phlebography in 70 consecutive patients and interobserver agreement was assessed in the last 48 patients at day 8. US was repeated in these 48 patients at day 13 and day 90.

RESULTS

Phlebography demonstrated a DVT in 18/70 (26%) patients, with five proximal and 13 distal and US in 23/70 (33%) patients, with eight proximal and 15 distal. Sensitivity and specificity of US with 95% CI were 94% (73-100) and 89% (76-96), respectively. Sensitivity in isolated distal vein thrombosis was 92% (67-99). The Kappa coefficient for agreement between observers was 0.84 (0.66-1.00). Follow-up showed a DVT in 15/48 (31%) patients on day 8, in 20/48 patients (42%) on day 13. DVT recurred in two patients during follow-up.

CONCLUSIONS

The incidence of asymptomatic DVT is still significant despite prophylaxis but most DVTs remain distal and occur in the first 2 weeks. Extended US could replace phlebography for systematic screening in clinical trials using surrogate endpoints in view of its high accuracy and reliability.

Bone mineral decrease in the leg with unilateral chronic occlusive arterial disease

OBJECTIVE

The links between osteoporosis and arteriosclerosis have been established by numerous epidemiological studies. Could arteriosclerosis induce bone mineral loss via ischemia or other pathological process? We carried out a comparative study of bone mineral density in both legs of patients with unilateral arterial disease of the lower limbs.

METHODS

We studied 25 patients, 22 men and 3 women, whose mean age was 62.3 years (range 35-88 years). These patients had unilateral lower limb arterial disease of at least 3 months duration with a systolic index at least 50% lower on the affected than on the healthy side. Bone mineral content (BMC) and bone mineral densities (BMD) of the femoral neck, femur, tibia, foot and ankle of the affected and the unaffected legs were measured by dual x-ray absorptiometry (Lunar DPXL) and the results compared.

RESULTS

Bone mineral density was significantly lower in the femur (-3.7%, p = 0.04), the foot and the ankle (-3%, p = 0.05) of the affected leg. There was a non-significant decrease in BMD of the whole femoral neck (-1.2%) and the trochanter (-4.4%, p = 0.08) on the affected side. Tibial bone mineral density was identical in both legs. Bone mineral content was lower on the affected side (-5.3%, p = 0.05) whereas fat mass and muscle mass were the same in both legs.

CONCLUSION

The ischemia resulting from arterial disease of the lower limbs appears to have a direct deleterious effect on bone mineralization.

Mutations in LIKE HETEROCHROMATIN PROTEIN 1 affect flowering time and plant architecture in Arabidopsis

In plants, recent studies have demonstrated links between the regulation of developmental processes and chromatin dynamics and organisation. Analysis of new mutations affecting overall plant architecture, leaf development and flowering time in Arabidopsis has allowed us to clone and characterise LHP1, the Drosophila heterochromatin protein 1 (HP1) homologue. LHP1 has the chromo and chromo shadow domains central to the function of animal proteins. Yeast two hybrid studies and in planta deletion experiments suggest similar modes of action in plants and animals via homodimer formation. In vivo localisation experiments revealed a specific subnuclear protein distribution in foci throughout the nucleus. Our data suggest that LHP1 may act as a main regulator of gene expression in plants, through formation of heterochromatin-like repressive complexes, to control developmental pathways involved in organ and cell size, and the vegetative to reproductive phase transition.

[Anticancer chemotherapy, risk factor for infection at the operated site in cervicofacial surgery]

BACKGROUND

In order to evaluate occurrence and risk factors for wound infection (WI) in head and neck uncontaminated surgery, we carried out a prospective study.

METHODS

From january 1997 through january 1999, we prospectively evaluated 212 wounds of all patients having uncontaminated head and neck surgery at the Oscar Lambret Cancer Center (neck dissections, parotidectomies, thyroidectomies, explorative cervicotomies, cutaneous resections). No antibiotic prophylaxis was given. WI was defined as a wound with pus. Statistical evaluation was performed using the chi 2 test. In univariate analysis, differences were considered significant p < 0.05.

RESULTS

The overall WI rate was 6.6% (14/212). In univariate analysis, previous chemotherapy is the only risk factor for WI were: (p < 0.00001). Multivariate analysis was not performed.

CONCLUSION

Like other cancer locations, chemotherapy was a major risk factor for WI. In these cases, a phase ill trial could confirm efficacy of standard antibiotic.

A case-acquisition and decision-support system for the analysis of group-average lactation curves

A case-acquisition and decision-support system was developed to support the analysis of group-average lactation curves and to acquire example cases from domain specialists. This software was developed through several iterations of a three-step approach involving 1) problem analysis and formulation in consultation with two dairy nutrition specialists; 2) development of a case-acquisition and decision-support prototype by the system developer; and 3) use of the prototype by the domain specialists to analyze and classify milk-recording data from example herds. The overall problem was decomposed into three subproblems: removal of outlier tests and lactation curves of individual cows; interpretation of group-average lactation curves; and diagnosis of detected abnormalities at the herd level through the identification of potential management deficiencies. For each subproblem, a software module was developed allowing the user to analyze both graphical and numerical performance representations and classify these representations using predefined linguistic descriptors. The example-based method for the development of the program proved to be very useful, facilitating the communication between system developer and domain specialists, and allowing the specialists to explore the appropriateness of the various prototypes developed. The resulting software represents a formalization of the approach to group-average lactation curve analysis, elicited from the two domain specialists. In future research, the case-acquisition and decision-support system will be complemented with knowledge to automate identified classification tasks, which will be captured through the application of machine-learning techniques to example cases, acquired from domain specialists using the software.