Group lactation from 7 or 14 days of age reduces piglet aggression at weaning compared to farrowing crate housing.

Early life experiences can affect social behaviour in later life, but opportunities for socio-behavioural development are often overlooked in current husbandry practices. This experiment investigated the effects of rearing piglets in two-stage group lactation (GL) system from 7 or 14 days of age on piglet aggression at weaning. Three lactation housing treatments were applied to a total of 198 piglets from 30 litters of multiparous sows. All dams farrowed in standard farrowing crates (FCs). Group lactation litters were transferred with their dam at 7 (GL7) or 14 days (GL14) postpartum to GL pens (one pen of five sows at 8.4 m2/sow and one pen of seven sows at 8.1 m2/sow, per GL treatment). Farrowing crate litters remained with their dam in a single litter until weaning. At weaning, 10 to 14 piglets from two unfamiliar litters from the same housing treatment were mixed into pens (n=5 pens/treatment) and their behaviour was continuously recorded for 3.5 h. For each pen, the frequency of aggressive bouts (reciprocal and non-reciprocal aggression lasting <5 s), the frequency and duration of fights (reciprocal aggression lasting ⩾5 s) and bullying events (non-reciprocal aggression lasting ⩾5 s) were recorded, along with whether interactions involved familiar or unfamiliar piglets. Aggressive bouts delivered by FC piglets were approximately 1.5 and 3.0 times more frequent than that delivered by GL7 and GL14 piglets, respectively (40.5, 16.7 and 9.9 bouts/pig, respectively; P<0.05). Fighting was more frequent (1.6, 0.3 and 0.4 fights/pig, respectively; P<0.001) and fights were longer (83, 15 and 32 s fight/pig, respectively; P<0.001) between FC piglets than between GL7 or GL14 piglets. Bullying did not differ between housing treatments (P>0.05). GL7 and GL14 piglets engaged in a similar number of fights with unfamiliar as familiar piglets, but FC piglets had almost three times as many fights with unfamiliar than with familiar piglets (P<0.05). This experiment confirms the benefits of GL housing for pig social development. Further investigation is required to determine whether mixing before 14 days postpartum has implications for other indicators of animal welfare and productivity in a two-stage GL housing system.

The short-term behavioural response of sows, but not gilts, to a social stimulus is related to sow aggressiveness in groups.

This study examined relationships between the behavioural response of pregnant gilts (n=200, gestation 1) and sows (n=200, gestation 2) to a live, similarly-aged female pig (unfamiliar pig test, UPT) and to a fibre-glass model pig (model pig test, MPT), and aggressive behaviour on the day after mixing (day 2). Sows with a short latency to make contact with an unfamiliar sow in the UPT were more likely to deliver high levels of aggression at day 2 of gestation 2 (P=0.005), but this relationship was stronger when a model pig was used (P<0.001). Similarly, sows with a long duration of tactile contact with the model pig in the MPT were more likely to deliver high levels of aggression at day 2 of gestation 2 (P=0.015), but this relationship was weaker than that between aggression and the latency to contact the model pig. When the terms the latency to contact the unfamiliar pig in the UPT and the model pig in the MPT, as well as the duration of contact with the model pig in the MPT, were included in an overall model of aggression at day 2 of gestation 2, behaviour towards the unfamiliar pig became not statistically significant (P>0.05). A strong relationship was not apparent with gilts (P>0.05). Thus, the socially inexperienced pig may not be an ideal model for sow behaviour. This study indicates that sows with a short latency to contact a model pig are more likely to be aggressive when mixed into groups.

The behaviour and welfare of sows and piglets in farrowing crates or lactation pens.

Temporary confinement during parturition and early postpartum may provide an intermediary step preceding loose housing that offers improvement in sow and piglet welfare. Three experiments were conducted to investigate the implications of replacing farrowing crates (FCs) with an alternative housing system from 3 days postpartum until weaning. In each experiment sows farrowed in FCs and were randomly allocated at day 3 of lactation to either a FC or a pen with increased floor space (lactation pen (LP)) until weaning. In experiment 1, piglet growth and sow and piglet skin injuries were recorded for 32 sows and 128 focal piglets in these litters. Behaviour around nursing and piglet behavioural time budgets were also recorded for 24 of these litters (96 focal piglets for time budgets). In experiment 2, measures of skin injury and behavioural time budgets were conducted on 28 sows and 112 focal piglets. The behavioural response of sows to piglet vocalisation (maternal responsiveness test (MRT)) was also assessed. In experiment 3, piglet mortality from day 3 of lactation until weaning was recorded in 672 litters over 12 months. While housing did not affect piglet weight gain in experiment 1, or piglet skin injuries in experiments 1 or 2, sows in both experiments sustained more injuries in LP than FC (experiment 1, 2.9 v. 1.4; experiment 2, 2.5 v. 0.8 lesions/sow; P0.05). Thus, housing sows and litters in LP from day 3 of lactation minimises piglet mortality while improving maternal behaviour in sows and social behaviour in piglets.

Individual variation in sow aggressive behavior and its relationship with sow welfare.

This study examined the relationships between individual sow aggressive behavior and sow welfare, based on aggression, skin injuries, and stress, in a total of 275 pregnant domestic sows. Over 4 time replicates, sows were randomly mixed into groups of 10 (floor space of 1.8 m/sow) within 7 d of insemination in both their first and second gestations (200 sows per gestation with 126 sows observed in both gestations). Measurements were taken on aggression (both delivered and received) at feeding, skin injuries, and plasma cortisol concentrations at d 2, 9, and 51 after mixing. Live weight gain, nonreproductive removals, litter size (born alive, total born, and stillborn piglets), and farrowing rate were also recorded. In both the first and the second gestations, sows were classified at d 2 after mixing as "submissive" (delivered little or no aggression at feeding relative to aggression received), "subdominant" (received more aggression at feeding than delivered), and "dominant" (delivered more aggression at feeding than received). In both gestations, sows classified as dominant at d 2 subsequently delivered more (gestation 1, < 0.01; gestation 2, < 0.01) and received less (gestation 1, < 0.01; gestation 2, < 0.01) aggression and gained the most weight (gestation 1, < 0.01; gestation 2, < 0.01). Dominant sows had the least skin injuries throughout gestation 1 ( = 0.04), and although submissive sows sustained the most skin injuries at d 9 and 51 of gestation 2, at d 2 the classifications did not differ in skin injuries ( < 0.01). Subdominant sows had the highest cortisol concentrations at d 2 of gestation 2, but there were no differences between classifications at d 9 and 51 in either gestation (gestation 1, > 0.05; gestation 2, = 0.02). There were no significant relationships between aggression classification and reproduction and nonreproductive removals ( > 0.05). In conclusion, sows classified as dominant at feeding at d 2 subsequently received less aggression at feeding, sustained fewer skin injuries, and had higher live weight gain. Submissive and subdominant sows in groups are likely to benefit from the provision of increased resources such as space and access to feed.

Effects of group housing on sow welfare: a review.

Factors that have been shown to impact the welfare of group-housed sows are discussed in this review. Floor space allowance markedly affects sow welfare. In addition to quantity of floor space, the quality of space is important: spatial separation between sows can be provided with visual or physical barriers and stalls. Whereas 1.4 m/sow is insufficient, further research is required to examine space effects in the range of 1.8 to 2.4 m/sow in more detail. The period immediately after mixing has the most pronounced effects on aggression and stress, and therefore, well-designed mixing pens offer the opportunity to reduce aggression, injury, and stress while allowing the social hierarchy to quickly form. Because hunger is likely to lead to competition for feed or access to feeding areas, strategies to reduce hunger between meals through higher feeding levels, dietary fiber, or foraging substrate should be examined. However, feeding systems, such as full-body feeding stalls, can also affect aggression and stress by providing protection at feeding, but deriving conclusions on this topic is difficult because research directly comparing floor feeding, feeding stalls, and electronic sow feeder systems has not been conducted. Familiar sows engage in less aggression, so mixing sows that have been housed together in the previous gestation may reduce aggression. Although there is evidence in other species that early experience may affect social skills later in life, there are few studies on the effects of early "socialization" on aggressive behavior of adult sows. Genetic selection has the potential to reduce aggression, and therefore, continued research on the opportunity to genetically select against aggressiveness and its broader implications is required. Most research to date has examined mixing sows after insemination and knowledge on grouping after weaning is limited.

Wave dispersion in a counterstreaming, relativistic thermal, magnetized, electron-positron plasma.

The dispersion equation is analyzed for waves in a strongly magnetized, electron-positron plasma in which counterstreaming electrons and positrons have a relativistic thermal distribution in their respective rest frames, for propagation parallel to the magnetic field. We derive the response tensor for the medium, demonstrate the dispersion curves for different temperatures, and discuss the differences from the cold-plasma case. Application to the case of pulsar magnetospheres is discussed.

Who should consent for research in adult intensive care? Preferences of patients and their relatives: a pilot study.

INTRODUCTION: Research in intensive care is necessary for the continuing advancement of patient care. In research, informed consent is considered essential for patient protection. In intensive care, the modalities of informed consent are currently being debated by both lawyers and the medical community. The preferences of patients and their relatives regarding informed consent for research in intensive care have never been assessed. The aim of this study was to investigate these preferences. METHODS: A pilot study conducted via a questionnaire mailed to patients and relatives who had experienced intensive care. RESULTS: 52/400 patient-relative pairs completed the questionnaire fully. If the patient was imagined to be conscious, 75% of patients and 77% of relatives believed the patient should be the person who should consent. If the patient was imagined to be unconscious, 72% of patients and 67% of relatives thought that a relative should be asked to consent. The majority of responders thought that at least two persons should consent. Their answers were concordant in 61-80% of cases, depending on the question. Patients (25%) and relatives (30%) did not feel free in their decision to participate in a study. The majority of patients and relatives wanted to consent by writing, indifferently with or without a witness. CONCLUSION: Patients are willing to decide on their own participation in a study. If they lose their capacity to decide for themselves, in the great majority of cases, they would agree to delegate the decision to a relative.

Wave dispersion in a counterstreaming, cold, magnetized, electron-positron plasma.

The dispersion equation is analyzed for waves in a strongly magnetized, electron-positron plasma in which counterstreaming electrons are cold in their respective rest frames. For propagation parallel to the magnetic field the dispersion equation factorizes into equations for two longitudinal modes and four transverse modes. Instabilities occur in both longitudinal and transverse modes, with the most notable being at low wave numbers where a longitudinal branch has purely imaginary frequency. For oblique propagation at small angles, the modes reconnect at points where the parallel modes intersect, either deviating away from each another, or being separated by a pair of complex modes. In addition, intrinsically oblique branches of the dispersion equation appear. The results are applied to an oscillating model for a pulsar magnetosphere, in which the oscillations are purely temporal with a frequency well below relevant wave frequencies, and in which the counterstreaming becomes highly relativistic. We assume that the medium may be treated as time stationary in treating the wave dispersion and wave growth. The wave properties, including the wave frequency, vary periodically with the phase of the oscillations. The fastest growing instability is when the counterstreaming is nonrelativistic or mildly relativistic. A given wave can experience bursts of growth over many oscillations. Mode coupling associated with the cyclotron resonance may be effective in generating the observed orthogonally polarized modes at phases of the oscillation where the (relativistic) cyclotron and wave frequencies are comparable.

Recognition and management of Lyme disease.

Lyme disease, the most common tick-borne illness in the United States, has an annual incidence of 0.5 percent in endemic areas. It most commonly occurs in the Northeast and upper Midwest, in areas that encourage and harbor the deer tick. The tick transmits an infection of the spirochete Borrelia burgdorferi that typically manifests as a localized skin lesion, erythema migrans. Rarely, Lyme disease manifests as localized arthritis, heart block or disease of the nervous system. Lyme disease is a clinical diagnosis, and laboratory tests should only be used to clarify diagnostic issues. The current standard for laboratory diagnosis includes a two-step approach using an initial immunoassay with a confirmatory Western blot. Treatment includes 10 to 21 days of oral doxycycline in nonpregnant adults or a similar course of amoxicillin in children or pregnant women. Overdiagnosis and overtreatment of Lyme disease have become common.

Issues in the management of human papillomavirus genital disease.

Human papillomavirus (HPV) infects epithelial cells at a variety of anatomic sites. Of the more than 80 types of this virus, approximately one third infect genital tissue. Genital infection can be clinical (warts), subclinical (abnormal Papanicolaou [Pap] smears or lesions visible only with magnification and application of acetic acid) or latent (infection with apparently normal tissue). Recent research has revealed a clear association between genital warts and HPV types 6 and 11, and between cervical cancer and HPV types 16, 18 and others. Women with genital warts who have normal Pap smears do not need colposcopy. All available therapies are suboptimal because HPV is not eradicated by treatment. However, the active disease expression can be eliminated by treatment. The approach to treatment will depend on each patient's personal characteristics and preferences.

Yield of review of systems in a self-administered questionnaire.

BACKGROUND: Family physicians frequently screen new patients with questionnaires that include a standard review of systems. The diagnostic yield of such questionnaires is unknown. METHODS: We retrospectively compared results of 248 patient questionnaires with the clinicians' dictated medical record in a university-based family medicine practice. Any positive responses in the review of systems section were compared with the medical record to determine whether they resulted in a new diagnosis and a therapeutic maneuver. RESULTS: The case-finding yield for the review of systems section as a whole was 10.5 percent. This yield compares favorably with other screening maneuvers in clinical practice. Individual questions had yields of 0.0 to 1.6 percent. The positive predictive value for a given yes response on the review of systems, defined as new diagnoses divided by total yes answers, was 3.3 percent. CONCLUSIONS: Compared with other case finding maneuvers in clinical practice, the review of systems questionnaire has a very acceptable yield. Its positive predictive value is low, however, and there are differences observed among physicians. Certain questions had a positive predictive value of 0.0 and could be deleted, which would produce a shortened review of systems section.

Using the theory of reasoned action (TRA) to understand the decision to use condoms in an STD clinic population.

The theory of reasoned action (TRA) provides useful information when designing health education interventions. In this study, 703 heterosexual STD clinic clients responded to a TRA-based survey. With steady partners, social norms and attitudes toward condom use were significant predictors of intention for both men and women. The interaction of attitude and norm increased prediction for men (R = .64, p < 0.001) and women (R = .70, p < 0.001). With casual partners, attitude was a predictor for men and social norm was a predictor for women. Prior use of condoms increased prediction for men (R = .38, p < 0.001) and women (R = .47, p < 0.001). Findings suggest that, in addition to traditional TRA model variables, the relationship between sexual partners and the individual's prior experience with condom use should be incorporated into attempts to understand this complex, dyadic behavior. Examining specific outcome and normative beliefs also provides important information for intervention design.

PIP: According to the Theory of Reasoned Action (TRA), the intention to perform a specific behavior is a linear function of the individual's attitudes related to performing the behavior and perceived social norms about the behavior. The ability of this theory to predict condom use intentions was tested in 703 heterosexual men and women registered at a health department sexually transmitted disease (STD) clinic in Seattle, Washington. Although 85% reported condom use at some point, few reported regular use (defined as 2/3 of the time). 40% reported sexual contact with a casual partner in the month preceding the survey, but only 21% had used condoms regularly with these partners. 64% acknowledged intercourse with a regular partner in the preceding month and condoms were used regularly by 16%. Overall, 75% of the sample had not used condoms regularly with steady or casual partners in the preceding month. Multiple regression analyses confirmed the relevance of the TRA model in accounting for a significant amount of the variance in condom use intention. Subjects had more positive attitudes, perceived stronger norms, and had stronger intentions toward condom use with casual than steady partners. The interaction of attitude and norm increased prediction for both men and women. For men, neither social norm alone nor the interaction of norm and attitude had an effect on the intention to use condoms with casual partners. Women who requested their partner to use condoms were more influenced by social norms, while male condom users were most influenced by their own attitudes. Among both men and women, previous users were more likely to intend to use condoms (R = .38 for men and .47 among women, p 0.001). TRA concepts should be incorporated into the design of health education programs aimed at promoting the use of condoms and other risk reduction behaviors.

Overuse syndromes of the hand and wrist.

Overuse syndromes are one of the most common occupational illnesses treated by primary care providers. Their pathophysiology parallels that of tenosynovitis. Occupational risk factors for overuse syndromes include repetition, high force, awkward joint posture, direct pressure, and vibration. Initial treatment is aimed at preventing fibrosis through rest, immobilization, and anti-inflammatory agents. Treatment must include identification and adjustment of occupational risk factors. Specific overuse syndromes are discussed, including tenosynovitis of the dorsal wrist extensor compartments and flexor tendons of the wrist, trigger finger, and carpal tunnel syndrome.

Common clinical presentations of occupational respiratory disorders.

Occupational lung disorders can mimic other respiratory diseases. Recurrent upper respiratory irritation, bronchitis, flu-like syndromes, adult-onset asthma and interstitial lung disease can be caused by dust, gases and fumes. The diagnosis of a work-related respiratory disorder requires a high index of suspicion and a thorough occupational history. The work-up may have to be more extensive than that for nonoccupational lung disease, because the casual agent usually must be identified and secondary issues, such as disability, compensation and prognosis, need to be considered. Treatment must include measures to decrease or eliminate exposure to the causative agent.

Racial/ethnic differences in the likelihood of cesarean delivery, California.

OBJECTIVES: The purpose of this study was to determine whether women's sociodemographic characteristics are independently associated with cesarean delivery. METHODS: A retrospective review was conducted of hospital discharge data for singleton first births in California in 1991. RESULTS: After insurance and personal, community, medical, and hospital characteristics had been controlled, Blacks were 24% more likely to undergo cesarean delivery than Whites; only among low-birthweight and county hospital births were Blacks not at a significantly elevated risk. Among women who resided in substantially non-English-speaking communities, who delivered high-birthweight babies, or who gave birth at for-profit hospitals, cesarean delivery appeared to be more likely among non-Whites and was over 40% more likely among Blacks than among Whites. CONCLUSIONS: The findings cannot establish causation, but the significant racial/ethnic disparities in delivery mode, despite adjustment for social, economic, medical, and hospital factors, suggest inappropriate influences on clinical decision making that would not be addressed by changes in reimbursement. If practice variations among providers are involved, de facto racial differences in access to optimal care may be indicated. The role of provider and patient attitudes and expectations in the observed racial/ethnic differentials should also be explored.

Pilot study of azithromycin for treatment of primary and secondary syphilis.

Azithromycin has in vitro activity against Treponema pallidum and is effective against experimental syphilis in rabbits. We undertook an open, noncomparative pilot study of oral azithromycin (500 mg once daily for 10 days) to treat 16 patients with primary or secondary syphilis who were seronegative for human immunodeficiency virus. Cure was documented for 11 of 13 patients observed > or = 3 months; three patients were lost to follow-up. The serological response of one patient with secondary syphilis was indeterminate, and one patient with primary syphilis had either relapse or reinfection. Four patients had mild gastrointestinal side effects, and another patient had an episode of nausea and vomiting; all side effects occurred in the first 3 days and resolved spontaneously as treatment continued. Azithromycin shows promise as an alternative agent for treatment of early syphilis; controlled trials and assessment of other dosage regimens are indicated.

Apolipoprotein E polymorphism modifies relation of hyperinsulinemia to hypertriglyceridemia.

The effect of apolipoprotein E polymorphism on the established relationships between glucose tolerance, plasma insulin levels, and plasma lipoprotein concentrations were investigated in a sample of women defined on the basis of apolipoprotein E phenotypes. In women with the apolipoprotein E epsilon 2 allele (n = 22), fasting plasma insulin and glucose and insulin areas under the curve measured during an oral glucose tolerance test were positively correlated with plasma triglyceride levels (0.48 < or = r < or = 0.70; P < 0.05). In this group, very-low-density lipoprotein cholesterol and very-low-density lipoprotein triglyceride concentrations were positively correlated with fasting insulin levels, the insulin area, and with the ratio of insulin area to glucose area. In women (n = 24) homozygous for the apolipoprotein E epsilon 3 allele (the most common allele), essentially similar associations were found. In contrast, in women (n = 17) with the apolipoprotein E epsilon 4 allele, no association was found between glucose tolerance, fasting and postglucose plasma insulin levels, and plasma lipid and lipoprotein levels. These results suggest that apolipoprotein E polymorphism substantially modifies the associations between glucose tolerance, plasma insulin levels, and plasma lipoprotein concentrations. Additional analysis of the data revealed that apolipoprotein E polymorphism did not alter the relationships between body fat distribution and fasting insulin and postglucose insulin levels, but no correlation was observed between fatness indexes and glucose tolerance among apolipoprotein E epsilon 2 carriers.(ABSTRACT TRUNCATED AT 250 WORDS)