Milk losses and dynamics during perturbations in dairy cows differ with parity and lactation stage.

Milk yield dynamics during perturbations reflect how cows respond to challenges. This study investigated the characteristics of 62,406 perturbations from 16,604 lactation curves of dairy cows milked with an automated milking system at 50 Belgian, Dutch, and English farms. The unperturbed lactation curve representing the theoretical milk yield dynamics was estimated with an iterative procedure fitting a model on the daily milk yield data that was not part of a perturbation. Perturbations were defined as periods of at least 5 d of negative residuals having at least 1 day that the total daily milk production was below 80% of the estimated unperturbed lactation curve. Every perturbation was characterized and split in a development and a recovery phase. Based hereon, we calculated both the characteristics of the perturbation as a whole, and the duration, slopes, and milk losses in the phases separately. A 2-way ANOVA followed by a pairwise comparison of group means was carried out to detect differences between these characteristics in different lactation stages (early, mid-early, mid-late, and late) and parities (first, second, and third or higher). On average, 3.8 ± 1.9 (mean ± standard deviation) perturbations were detected per lactation in the first 305 d after calving, corresponding to an estimated 92.1 ± 135.8 kg of milk loss. Only 1% of the lactations had no perturbations. On average, 2.3 kg of milk was lost per day in the development phase, while the recovery phase corresponded to an average increase in milk production of 1.5 kg/d, and these phases lasted an average of 10.1 and 11.6 d, respectively. Perturbation characteristics were significantly different across parity and lactation stage groups, and early and mid-early perturbations in higher parities were found to be more severe with faster development rates, slower recovery rates, and higher milk losses. The method to characterize perturbations can be used for precision phenotyping purposes that look into the response of cows to challenges or that monitor applications (e.g., to evaluate the development and recovery of diseases and how these are affected by preventive actions or treatments).

Productive life span and resilience rank can be predicted from on-farm first-parity sensor time series but not using a common equation across farms.

A dairy cow's lifetime resilience and her ability to recalve gain importance on dairy farms, as they affect all aspects of the sustainability of the dairy industry. Many modern farms today have milk meters and activity sensors that accurately measure yield and activity at a high frequency for monitoring purposes. We hypothesized that these same sensors can be used for precision phenotyping of complex traits such as lifetime resilience or productive life span. The objective of this study was to investigate whether lifetime resilience and productive life span of dairy cows can be predicted using sensor-derived proxies of first-parity sensor data. We used a data set from 27 Belgian and British dairy farms with an automated milking system containing at least 5 yr of successive measurements. All of these farms had milk meter data available, and 13 of these farms were also equipped with activity sensors. This subset was used to investigate the added value of activity meters to improve the model's prediction accuracy. To rank cows for lifetime resilience, a score was attributed to each cow based on her number of calvings, her 305-d milk yield, her age at first calving, her calving intervals, and the DIM at the moment of culling, taking her entire lifetime into account. Next, this lifetime resilience score was used to rank the cows within their herd, resulting in a lifetime resilience ranking. Based on this ranking, cows were classified in a low (last third), moderate (middle third), or high (first third) resilience category within farm. In total, 45 biologically sound sensor features were defined from the time series data, including measures of variability, lactation curve shape, milk yield perturbations, activity spikes indicating estrous events, and activity dynamics representing health events (e.g., drops in daily activity). These features, calculated on first-lactation data, were used to predict the lifetime resilience rank and, thus, to predict the classification within the herd (low, moderate, or high). Using a specific linear regression model progressively including features stepwise selected at farm level (cutoff P-value of 0.2), classification performances were between 35.9 and 70.0% (46.7 ± 8.0, mean ± SD) for milk yield features only, and between 46.7 and 84.0% (55.5 ± 12.1, mean ± SD) for lactation and activity features together. This is, respectively, 13.7 and 22.2% higher than what random classification would give. Moreover, using these individual farm models, only 3.5 and 2.3% of cows were classified high when they were actually low, or vice versa, whereas respectively 91.8 and 94.1% of wrongly classified animals were predicted in an adjacent category. The sensor features retained in the prediction equation of the individual farms differed across farms, which demonstrates the variability in culling and management strategies across farms and within farms over time. This lack of a common model structure across farms suggests the need to consider local (and evidence-based) culling management rules when developing decision support tools for dairy farms. With this study we showed the potential of precision phenotyping of complex traits based on biologically meaningful features derived from readily available sensor data. We conclude that first-lactation milk and activity sensor data have the potential to predict cows' lifetime resilience rankings within farms but that consistency between farms is currently lacking.

Addition of meloxicam to the treatment of clinical mastitis improves subsequent reproductive performance.

A blinded, negative controlled, randomized intervention study was undertaken to test the hypothesis that addition of meloxicam, a nonsteroidal anti-inflammatory drug, to antimicrobial treatment of mild to moderate clinical mastitis would improve fertility and reduce the risk of removal from the herd. Cows (n=509) from 61 herds in 8 regions (sites) in 6 European countries were enrolled. Following herd-owner diagnosis of mild to moderate clinical mastitis within the first 120 d of lactation in a single gland, the rectal temperature, milk appearance, and California Mastitis Test score were assessed. Cows were randomly assigned within each site to be treated either with meloxicam or a placebo (control). All cows were additionally treated with 1 to 4 intramammary infusions of cephalexin and kanamycin at 24-h intervals. Prior to treatment and at 14 and 21 d posttreatment, milk samples were collected for bacteriology and somatic cell count. Cows were bred by artificial insemination and pregnancy status was subsequently defined. General estimating equations were used to determine the effect of treatment (meloxicam versus control) on bacteriological cure, somatic cell count, the probability of being inseminated by 21 d after the voluntary waiting period, the probability of conception to first artificial insemination, the number of artificial insemination/conception, the probability of pregnancy by 120 or 200 d postcalving, and the risk of removal by 300 d after treatment. Cox's proportional hazards models were used to test the effect of treatment on the calving to first insemination and calving to conception intervals. Groups did not differ in terms of age, clot score, California Mastitis Test score, rectal temperature, number of antimicrobial treatments given or bacteria present at the time of enrollment, but cows treated with meloxicam had greater days in milk at enrollment. Cows treated with meloxicam had a higher bacteriological cure proportion than those treated with the placebo [0.66 (standard error=0.04) versus 0.50 (standard error=0.06), respectively], although the proportion of glands from which no bacteria were isolated posttreatment did not differ between groups. No difference was observed in the somatic cell count between groups pre- or posttreatment. The proportion of cows that underwent artificial insemination by 21 d after the voluntary waiting period was unaffected by treatment. Treatment with meloxicam was associated with a higher proportion of cows conceiving to their first artificial insemination (0.31 versus 0.21), and a higher proportion of meloxicam-treated cows were pregnant by 120 d after calving (0.40 versus 0.31). The number of artificial inseminations required to achieve conception was lower in the meloxicam compared with control cows (2.43 versus 2.92). No difference was observed between groups in the proportion of cows pregnant by 200 d after calving or in the proportion of cows that were culled, died, or sold by 300 d after calving (17% versus 21% for meloxicam versus control, respectively). It was concluded that use of meloxicam, in conjunction with antimicrobial therapy, for mild to moderate cases of clinical mastitis, resulted in a higher probability of bacteriological cure, an increased probability of conception to first artificial insemination, fewer artificial inseminations, and a greater proportion of cows pregnant by 120 d in milk.

Reduction in daily milk yield associated with subclinical bovine herpesvirus 1 infection.

The aim of this observational cohort study was to investigate the potential economic impact of subclinical bovine herpesvirus 1 (BoHV-1) infection in a commercial UK dairy herd in terms of milk yield depression. Infection status of cows (infected or not infected) was assigned from serology on a single occasion. A multi-level linear model was used to evaluate the impact of infection status on milk production, using milk records that were routinely collected over two years. BoHV-1 seropositive cows produced 2.6 kg/day less milk over the study period compared with cows that were seronegative. This result highlights the importance of appropriate management of risks associated with subclinical infection with BoHV-1 as part of proactive herd health and production management.

Effective services to support children in special circumstances.

BACKGROUND: Children living in special circumstances, defined as those who are at risk of achieving poorer outcomes than their peers, have a particular need of good quality, accessible services to promote their health and well-being, yet may be least likely to receive them. AIMS: This review considers the evidence for effective services to support children living in five kinds of special circumstances: (1) those at risk of offending; (2) teenage parents; (3) children whose parents have drug, alcohol or mental health problems; (4) children living with domestic violence; and (5) children who have been abused or neglected. In practice, there is often considerable overlap between these groups, and many children face multiple disadvantage. The review also aims to identify effective strategies for making support services more accessible to hard-to-reach groups. METHODS: Relevant literature was identified through searches of databases and websites, and consultation with experts. Given the broad scope of the topic, the aim was to provide an overview of best evidence rather than to undertake a systematic review. RESULTS: Similar themes underpin the most promising approaches to supporting children in special circumstances. These include: (1) a holistic, multi-agency approach addressing the needs of the whole child rather than compartmentalising children's social, educational, health and care needs; (2) the importance of links between adults' and children's services so that children who are in need because of their parents' circumstances can be identified and supported; and (3) the value of providing children in special circumstances with intensive, targeted support within a framework of universal provision. CONCLUSIONS: Overall, there is a lack of well-designed evaluations of the effectiveness of UK services and programmes for children in special circumstances. The existing evidence base would be strengthened by the development of better outcome measures, by exploring the characteristics of effective services from the perspective of different stakeholders (including children and young people themselves) and by extending the current problem-oriented approach to consider the factors that promote resilience and coping.

Evaluation of the rat bone marrow and peripheral blood micronucleus test using monocrotaline.

The present study was performed as part of the 9th collaborative trial of the CSGMT (Collaborative Study Group for the Micronucleus Test) to evaluate the performance of the rat micronucleus test in detection of clastogenic agents. Temporary fluorescent staining using acridine orange (AO) was compared with permanent staining using a modified Feulgen technique for bone marrow and Giemsa for blood. The Feulgen and AO methods were both found to be suitable for demonstrating micronucleus induction in rat bone marrow following oral administration of monocrotaline and cyclophosphamide. Induction of micronuclei was also shown using rat blood. The simple AO supravital method described produced uniformly stained preparations which were extremely easy to assess and interpret. The AO method was preferred to Giemsa for analysis of blood, but it was essential to analyse samples within 4 days of collection to avoid excessive deterioration of cells. Because of the relatively low number of micronucleated cells found in rat blood, it is suggested that examination of a larger number of cells may be necessary to achieve a similar sensitivity to the bone marrow assay for routine screening.

Assessment of the potential in vivo genotoxicity of three trihalomethanes: chlorodibromomethane, bromodichloromethane and bromoform.

Chlorination of drinking water results in the formation of chlorodibromomethane, bromodichloromethane and bromoform. These trihalomethanes have all shown evidence of genotoxicity in bacterial and mammalian cell systems in vitro and some evidence of carcinogenicity in rodents. Chlorodibromomethane and bromodichloromethane have previously been tested in the mouse micronucleus test and did not induce chromosome damage, but results from two previous micronucleus tests on bromoform are somewhat contradictory. In the present study, bromoform was tested in the mouse bone marrow micronucleus test in order to reassess the response in this system; all three compounds were evaluated using the rat liver unscheduled DNA synthesis test. Trihalomethanes are well absorbed by the oral route which was selected for this study as being that most relevant to humans. Bromoform did not induce micronuclei in mouse bone marrow, and chlorodibromomethane, bromodichloromethane and bromoform did not cause unscheduled DNA synthesis in rat liver. These trihalomethanes have not shown any evidence of genotoxicity in vivo and are most unlikely to have any significant genotoxic activity in mammals. Their mode of action as rodent carcinogens remains unexplained.

Assessment of the potential in vivo genotoxicity of fluoranthene.

Fluoranthene is a ubiquitous environmental pollutant. Although fluoranthene is mutagenic in bacterial and mammalian in vitro cell systems following metabolic activation by rat liver fraction, information on in vivo mutagenicity is lacking and studies on tumour initiating activity in mice are equivocal. In the present study, the potential genetic hazard to man was assessed using the mouse bone marrow micronucleus and rat liver unscheduled DNA synthesis test systems. Fluoranthene did not show any evidence of genotoxicity in either of the in vivo assays following acute oral administration at levels of up to 2000 mg/kg b.w.

An investigation into the relationship between human beings and Norfolk terriers.

Two Norfolk Terriers were used as experimental subjects to investigate the means by which human beings relate to Norfolk Terriers in maintaining their overall dental health. The study was divided into two parts: the Hard Cheese Study (HCS) and the Oral Hygiene Study (OHS). The difficulties in conducting experiments on this breed are highlighted and an evaluation of random error in measurements is undertaken using an Index termed Jaw Occlusions in a Kennel Environment (JOKE).

Quantitative scintigraphy in diagnosis and management of plantar fasciitis (calcaneal periostitis): concise communication.

We have found that Tc-99m methylene diphosphonate imaging of the heel is of diagnostic value in the "painful heel syndrome," permitting positive identification of the site of inflammation in cases where radiography is unhelpful. With this technique, tracer uptake in the heel is susceptible to quantification, allowing a serial and objective assessment of response to therapy.