Effect of feeding heat-treated colostrum on risk for infection with Mycobacterium avium ssp. paratuberculosis, milk production, and longevity in Holstein dairy cows.

In summer 2007, a randomized controlled field trial was initiated on 6 large Midwest commercial dairy farms to investigate the effect of feeding heat-treated (HT) colostrum on transmission of Mycobacterium avium ssp. paratuberculosis (MAP) and on future milk production and longevity within the herd. On each farm, colostrum was collected daily from fresh cows, pooled, divided into 2 aliquots, and then 1 aliquot was heat-treated in a commercial batch pasteurizer at 60°C for 60min. A sample from each batch of colostrum was collected for PCR testing (MAP-positive vs. MAP-negative). Newborn heifer calves were removed from the dam within 30 to 60min of birth and systematically assigned to be fed 3.8 L of either fresh (FR; n=434) or heat-treated (HT; n=490) colostrum within 2h of birth. After reaching adulthood (>2 yr old), study animals were tested once annually for 3 yr (2010, 2011, 2012) for infection with MAP using serum ELISA and fecal culture. Lactation records describing milk production data and death or culling events were collected during the 3-yr testing period. Multivariable model logistic and linear regression was used to investigate the effect of feeding HT colostrum on risk for testing positive to MAP during the 3-yr testing period (positive/negative; logistic regression) and on first and second lactation milk yield (kg/cow; linear regression), respectively. Cox proportional hazards regression was used to investigate the effect of feeding HT colostrum on risk and time to removal from the herd. Fifteen percent of all study animals were fed PCR-positive colostrum. By the end of the 3-yr testing period, no difference was noted in the proportion of animals testing positive for MAP, with either serum ELISA or fecal culture, when comparing the HT group (10.5%) versus the FR group (8.1%). There was no effect of treatment on first- (HT=11.797kg; FR=11,671kg) or second-lactation (HT=11,013kg; FR=11,235kg) milk production. The proportion of cows leaving the herd by study conclusion was not different for animals originally fed HT (68.0%) versus FR (71.7%) colostrum. Although a previous study showed that feeding HT colostrum (60°C for 60min) produces short-term benefits, including improved passive transfer of IgG and reduced morbidity in the preweaning period, the current study found no benefit of feeding HT colostrum on long-term outcomes including risk for transmission of Mycobacterium avium ssp. paratuberculosis, milk production in the first and second lactation, and longevity within the herd.

Cow-level association between serum 25-hydroxyvitamin D concentration and Mycobacterium avium subspecies paratuberculosis antibody seropositivity: a pilot study.

Vitamin D deficiency has been associated with various human diseases. Therefore, the objective of this study was to evaluate the cow-level association between serum 25-hydroxyvitamin D [25(OH)D] concentration and Mycobacterium avium ssp. paratuberculosis (MAP) seropositivity of dairy cows, adjusting for diet, breed, hair coat color, stage of lactation, reproductive status, and cow age. The sera of 80 MAP antibody ELISA-positive and 80 test-negative herd mates from 5 Minnesota dairy herds were analyzed for 25(OH)D and 1,25-dihydroxyvitamin D [1,25(OH)(2)D]. The cows' age, production records, and hair coat color were recorded. Additionally, feed samples were obtained and analyzed for vitamin D(2) and vitamin D(3) content. A linear mixed model was used to identify potential predictors for serum 25(OH)D concentration, accounting for herd of origin. The majority of rations analyzed had over 22,000 IU of vitamin D/day (maximum: 52,000 I U/d) and the study cows' average serum 25(OH)D concentration was 62.5 ± 13.8 ng/mL. Serum ELISA-positive cows had, on average, 5.3 ng/mL lower 25(OH)D serum levels than test-negative herd mates. The reproductive status of cows was also associated with the 25(OH)D levels, with fresh cows having the lowest serum concentration. In this cross-sectional study, a temporal or causal association between MAP antibody ELISA status and serum 25(OH)D concentration could not be evaluated. In addition, the high levels of vitamin D in the rations of participating farms and the average 25(OH)D serum concentration suggest that additional supplementation with vitamin D in the ration is likely to be ineffective.

Heat-treated colostrum and reduced morbidity in preweaned dairy calves: results of a randomized trial and examination of mechanisms of effectiveness.

A randomized controlled clinical trial was conducted using 1,071 newborn calves from 6 commercial dairy farms in Minnesota and Wisconsin, with the primary objective being to describe the effects of feeding heat-treated colostrum on serum immunoglobulin G concentration and health in the preweaning period. A secondary objective was to complete a path analysis to identify intermediate factors that may explain how feeding heat-treated colostrum reduced the risk for illness. On each farm, colostrum was collected each day, pooled, and divided into 2 aliquots; then, one aliquot was heat-treated in a commercial batch pasteurizer at 60°C for 60 min. Samples of fresh and heat-treated colostrum were collected for standard microbial culture (total plate count and total coliform count, cfu/mL) and for measurement of immunoglobulin G concentrations (mg/mL). Newborn calves were removed from the dam, generally within 30 to 60 min of birth, and systematically assigned to be fed 3.8L of either fresh (FR, n=518) or heat-treated colostrum (HT, n=553) within 2h of birth. Venous blood samples were collected from calves between 1 and 7d of age for measurement of serum IgG concentrations (mg/mL). All treatment and mortality events were recorded by farm staff between birth and weaning. Regression models found that serum IgG concentrations were significantly higher in calves fed HT colostrum (18.0 ± 1.5 mg/mL) compared with calves fed FR colostrum (15.4 ± 1.5 mg/ml). Survival analysis using Cox proportional hazards regression indicated a significant increase in risk for a treatment event (any cause) in calves fed FR colostrum (36.5%, hazard ratio=1.25) compared with calves fed HT colostrum (30.9%). In addition, we observed a significant increase in risk for treatment for scours in calves fed FR colostrum (20.7%, hazard ratio=1.32) compared with calves fed HT colostrum (16.5%). Path analysis suggested that calves fed HT colostrum were at lower risk for illness because the heat-treatment process caused a significant reduction in colostrum total coliform count, which was associated with a reduced risk for illness as a function of improved serum IgG concentrations.

Heat treatment of colostrum on commercial dairy farms decreases colostrum microbial counts while maintaining colostrum immunoglobulin G concentrations.

This study was conducted on 6 commercial dairy farms in Minnesota and Wisconsin to describe the effect of heat treatment (at 60°C for 60 min) on colostrum, on colostrum bacteria counts, and immunoglobulin G concentrations. First-milking colostrum was collected each day, pooled, divided into 2 aliquots, and then 1 aliquot was heat treated in a commercial batch pasteurizer at 60°C for 60 min. Frozen samples of pre- and post- heat-treated colostrum were submitted for standard microbial culture (total plate count and total coliform count, cfu/mL) and testing for immunoglobulin G concentrations (mg/mL). Data were analyzed from 266 unique batches of colostrum. Linear regression showed that heat treatment decreased colostrum total plate counts (-2.25 log(10)) and coliform counts (-2.49 log(10)), but, overall, did not affect colostrum IgG concentration. Though higher-quality batches of colostrum did experience a greater magnitude of loss of IgG as a result of heat treatment as compared with lower- or intermediate-quality batches of colostrum, the colostral IgG concentrations in these batches remained high overall, and within acceptable limits for feeding. This study demonstrates that batch heat treatment of colostrum at 60°C for 60 min can be successfully conducted on commercial dairy farms by farm staff to decrease colostrum microbial counts while maintaining colostrum IgG concentrations.

Predicting violence among cocaine, cannabis, and alcohol treatment clients.

In this study, the relationship between the use of various substances, selected psychosocial characteristics, and violence was examined. Groups of subjects in treatment for a primary problem with cocaine (n=300), cannabis (n=128), alcohol (n=110), other drugs (33), tobacco (n=249) or gambling (n=199) completed a self-administered questionnaire. The questionnaire included questions on various psychosocial scales (i.e., aggressive personality, chronic stress, sleep problems, impulsivity, disrespect for the law and social supports), frequency of drug and alcohol use, and violence in the past year. For the univariate analyses, all of the drug and psychosocial variables were significantly related to violence. In the multivariate analyses, frequency of cocaine and alcohol use, disrespect for the law, aggressive personality, age and sex were significantly related to violence. The findings point to multi-causal explanations; however, both alcohol and cocaine use appear to play a significant role in explaining violence.

Passive transfer of immunoglobulin G and preweaning health in Holstein calves fed a commercial colostrum replacer.

The objective of this study was to describe passive transfer of IgG and preweaning health in newborn calves fed a commercially available plasma-derived colostrum replacement (CR) product or maternal colostrum (MC). Twelve commercial Holstein dairy farms enrolled singleton newborn heifer calves to be fed fresh MC (n = 239 calves) or one dose of CR containing 125 g of Ig (n = 218 calves) as the first colostrum feeding. For 7 of these farms that routinely provided a second feeding of 1.9 L of MC to their calves 8 to 12 h after the first colostrum feeding, calves assigned to the CR treatment group were offered a second feeding consisting of 1.9 L of commercial milk replacer supplemented with one dose of a commercially available plasma-derived colostrum supplement, containing 45 g of Ig per dose, 8 to 12 h after the first colostrum feeding. A blood sample was collected from all calves between 1 to 8 d of age for serum IgG and total protein (TP) determination, and records of all treatment and mortality events were collected until weaning. Serum IgG and TP concentrations were significantly higher in calves fed MC (IgG = 14.8 +/- 7.0 mg/mL; TP = 5.5 +/- 0.7 g/dL) compared with calves fed CR (IgG = 5.8 +/- 3.2 mg/mL; TP = 4.6 +/- 0.5 g/dL). The proportion of calves with failure of passive transfer (serum IgG <10.0 mg/mL) was 28.0 and 93.1% in the MC and CR treatment groups, respectively. Though a trend was present, the proportion of calves treated for illness was not statistically different for calves fed MC (51.9%) vs. CR (59.6%). Total number of days treated per calf (MC = 1.7; CR = 2.0), treatment costs per calf (MC = $10.84; CR = $11.88), and proportion of calves dying (MC = 10.0%; CR = 12.4%) was not different between the 2 colostrum treatment groups. The mean serum total protein concentration predictive of successful passive transfer (serum IgG = 10 mg/mL) was 5.0 g/dL in calves fed MC or CR. Long-term follow-up of these calves (to maturity) is ongoing to describe the effects of feeding CR on longevity, productivity, risk for Johne's disease, and economics.

Prevalence of antimicrobial resistance among Salmonella on midwest and northeast USA dairy farms.

The objective of this study was to determine the prevalence of antimicrobial resistance among Salmonella isolated from dairy herds in New York, Minnesota, Michigan, and Wisconsin, USA. Serogroup and antimicrobial susceptibility characteristics were determined for Salmonella from cattle and environmental samples collected during August 2000-October 2001 as part of a longitudinal study where 129 herds were visited at 2-month intervals. Salmonella isolates were tested (using a broth microdilution method) for susceptibility to amoxicillin/clavulanic acid, ampicillin, ceftiofur, ceftriaxone, cephalothin, chloramphenicol, ciprofloxacin, gentamicin, kanamycin, nalidixic acid, streptomycin, sulfamethoxazole, tetracycline, and trimethoprim/sulfamethoxazole. Of the 1506 isolates tested for minimum inhibitory concentrations to these 14 antimicrobial agents, 81.2% were pan-susceptible and for most herds (81.6%) the predominant antimicrobial resistance pattern was pan-susceptible. At least 1 Salmonella isolate resistant to 5 or more antimicrobial agents was found on 23.6% of herds. This resistance phenotype was most common among serogroups B and E1 and among samples from calves and farmer-designated sick cows. Resistant samples most frequently exhibited resistance to tetracycline, streptomycin, and/or ampicillin. No samples were resistant to ceftriaxone (though 13 were in the intermediate range), and very few samples were resistant to ciprofloxacin (n=1), nalidixic acid (n=5), or trimethoprim/sulfamethoxazole (n=7).

Heat-treatment of bovine colostrum. II: effects of heating duration on pathogen viability and immunoglobulin G.

Batches (30-L) of first-milking bovine colostrum, inoculated with Mycoplasma bovis (10(8) cfu/mL), Listeria monocytogenes (10(6) cfu/mL), Escherichia coli O157:H7 (10(6) cfu/mL), Salmonella enteritidis (10(6) cfu/mL), and Mycobacterium avium subsp. paratuberculosis (Map; 10(3) cfu/mL), were heat-treated at 60 degrees C for 120 min in a commercial on-farm batch pasteurizer system. Duplicate 50-mL subsamples of colostrum were collected at 15-min intervals throughout the heat-treatment process for the purpose of bacterial culture and for measurement of IgG concentration (mg/mL) and antibody activity [log2(bovine viral diarrhea virus type 1 serum neutralization titer)]. Four replicate batches of colostrum were run for each of the 5 pathogens studied. There was no effect of heating moderate- to high-quality colostrum at 60 degrees C for at least 120 min on mean IgG concentration (pre = 60.5 mg/mL; post = 59.1 mg/mL). Similarly, there was no effect of heat-treatment on the mean log2 bovine viral diarrhea virus type 1 serum neutralization titer (pre = 12.3; post = 12.0). Viable M. bovis, L. monocytogenes, E. coli O157:H7, and S. enteritidis added to colostrum could not be detected after the colostrum was heat-treated at 60 degrees C for 30 min. Average bacteria counts showed that Map was not detected when batches were heated at 60 degrees C for 60 min. Although the authors believe that heat-treating colostrum at 60 degrees C for 60 min should be sufficient to eliminate Map from colostrum in most situations, further research is needed to determine whether these findings may be replicated, given that variability was observed in Map culture results.

Heat treatment of bovine colostrum. I: effects of temperature on viscosity and immunoglobulin G level.

The objective of this study was to identify the critical temperature, at or below which heat-treatment of bovine colostrum would produce no significant changes in viscosity, IgG concentration, or Ig activity. Results of preliminary work, using a Rapid Visco Analyzer (RVA) to heat 50-mL aliquots from 6 unique batches of bovine colostrum at 59, 60, 61, 62, and 63 degrees C, suggested that colostrum could be heated to 60 degrees C for up to 120 min without changing viscosity or IgG concentration. This finding was confirmed by heating 50-mL aliquots from 30 unique batches of colostrum in an RVA for 120 min at 60 and 63 degrees C. Heating colostrum to 63 degrees C resulted in an estimated 34% decrease in IgG concentration and 33% increase in viscosity. However, there was no difference in IgG concentration between preheat-treated (73.4 +/- 26.5 mg/mL) and post-heat-treated (74.5 +/- 24.3 mg/mL) samples after heating colostrum to 60 degrees C in an RVA for 120 min. Similarly, viscosity was unaffected after heating colostrum to 60 degrees C in an RVA for 120 min. High quality colostrum (> or =73.0 mg/mL) suffered greater losses of IgG and greater viscosity changes when heated to 63 degrees C than did moderate quality colostrum (<73.0 mg/mL). However, the effects of colostrum quality were minor if high quality colostrum was only heated to 60 degrees C. The results of a bovine viral diarrhea serum neutralization assay suggested that antibody activity was unchanged after heating colostrum to either 60 or 63 degrees C. However, these results were interpreted as being inconclusive due to a high proportion of missing results because of the congealing of many samples after heat treatment. The results of this study indicate that 50-mL volumes of bovine colostrum can be heat treated at 60 degrees C for up to 120 min in an RVA without affecting IgG concentration or viscosity.

Effect of on-farm commercial batch pasteurization of colostrum on colostrum and serum immunoglobulin concentrations in dairy calves.

The objectives were to describe the effect of on-farm commercial batch pasteurization on immunoglobulin (IgG) concentrations and the fluid and feeding characteristics of colostrum and to compare serum IgG concentrations in calves fed fresh versus pasteurized colostrum. Newborn calves (123) were systematically allocated to dietary treatments of either fresh or pasteurized colostrum at both the first and second colostrum feedings. The IgG concentrations were measured for batches of colostrum fed fresh and in pre and postpasteurized samples for batches of colostrum fed after being pasteurized and in calf serum. Pasteurization reduced colostrum IgG concentration, with the percentage reduction averaging 58.5 and 23.6% for 95-L and 57-L batches, respectively. Pasteurizing high quality colostrum in 57-L (vs. 95-L) batches resulted in higher IgG concentrations in the end product. Pasteurization of 57-L batches produced colostrum of normal or only mildly thickened consistency that could be fed to calves. Serum IgG concentrations were higher for calves fed fresh colostrum and for calves with a shorter time interval (< or = 6 h) between first and second colostrum feedings. After controlling for the time interval between feedings, serum IgG concentrations were significantly higher for 40 calves fed unpasteurized (19.1 mg/ml) vs. 55 calves fed pasteurized colostrum (9.7 mg/ml) for calves fed 2 L at first feeding. By contrast, there was no difference in serum IgG concentrations between 8 calves fed unpasteurized (16.1 mg/ml) and 20 calves fed pasteurized colostrum (13.5 mg/ml) after calves were fed 4 L at the first feeding. While the latter results suggest that pasteurizing colostrum may work for producers with excellent colostrum management, these results are preliminary and should be interpreted with caution, given the fewer number of calves and batches of colostrum involved with this second comparison.

Further delineation of the sequences required for the expression and physiological regulation of the vasopressin gene in transgenic rat hypothalamic magnocellular neurones.

We have introduced transgenes into rats with a view to defining genomic regions that mediate the cell-specific and physiological regulation of the vasopressin gene. These transgenes consist of the rat vasopressin structural gene with a reporter inserted into exon III, flanked by different lengths of upstream and downstream sequences. 11-VCAT-3 is flanked by 11 kbp of upstream sequences and 3 kbp of downstream sequences. The previously described 5-VCAT-3 is flanked by 5 kbp of upstream and 3 kbp of downstream sequences. 3-VCAT-3 has 3 kbp of upstream and 3 kbp of downstream sequences, and 3-VCAT-0.2 is flanked by 3 kbp of upstream and 0.2 kbp of downstream sequences. All four transgenes elicit the same expression patterns; low basal expression is seen in the magnocellular supraoptic and paraventricular nuclei, and is negligible in the suprachiasmatic nucleus. Expression increases markedly in vasopressin magnocellular cells following dehydration. The sequences responsible for the cell-specific expression and physiological regulation of our transgenes thus reside within the confines of the smallest construct studied, 3-VCAT-0.2.

Results of a pilot program for training bar staff in preventing aggression.

One hundred and twenty-one staff from eight bars in Ontario, Canada participated in a three-hour training program that used a peer learning model to teach problem-solving skills regarding the prevention and management of aggressive behavior in bars. Participants showed significant positive changes in knowledge and attitudes regarding effective approaches to preventing aggression. The majority of participants reported that the training made them think about ways they handed problem situations and that they would change the way they handle problems in the future. Participants rated most aspects of the training as very useful, especially the group discussion. The program illustrates the potential for increasing skills and knowledge of bar staff in preventing aggression and associated injury.

Complementary and alternative medicine in pregnancy: a survey of North Carolina certified nurse-midwives.

OBJECTIVE: To determine the prevalence and types of complementary and alternative medicine therapies used by certified nurse-midwives in North Carolina. METHODS: Surveys were sent to all 120 licensed certified nurse-midwives in North Carolina requesting information concerning their recommendations for use of complementary and alternative medicine for their pregnant or postpartum patients. RESULTS: Eighty-two responses were received (68.3%). Seventy-seven (93.9%) reported recommending complementary and alternative medicine to their pregnant patients in the past year. Forty-seven (57.3%) reported recommending complementary and alternative medicine to more than 10% of patients. The percentage of nurse-midwives who recommended each type of complementary and alternative medicine was as follows: herbal therapy (73.2%), massage therapy (67.1%), chiropractic (57.3%), acupressure (52.4%), mind-body interventions (48.8%), aromatherapy (32.9%), homeopathy (30.5%), spiritual healing (23.2%), acupuncture (19.5%), and bioelectric or magnetic applications (14.6%). The 60 respondents who reported prescribing herbal therapies gave them for the following indications: nausea and vomiting, labor stimulation, perineal discomfort, lactation disorders, postpartum depression, preterm labor, postpartum hemorrhage, labor analgesia, and malpresentation. CONCLUSION: Complementary and alternative medicine, especially herbal therapy, is commonly prescribed to pregnant women by nurse-midwives in North Carolina.

Compartment-mediated dissection for papillary thyroid cancer.

There is considerable controversy surrounding the appropriate treatment of papillary thyroid carcinoma (PTC), most of which centers around the extent of thyroidectomy. Despite the advocation of less than total thyroidectomy by many surgeons, there is a renewed interest by others, mainly in Europe and Japan, in the performance of routine total thyroidectomy and extensive lymph-node dissection for PTC. This has been shown to be an effective strategy for medullary thyroid carcinoma, which is not responsive to thyroid suppression or radioactive iodine treatment. PTC, however, is well treated by these adjuvant modalities and, in general, has an excellent prognosis. The benefit of extensive operations for routine cases of PTC has not been proven, and this practice is not employed by most surgeons in the United States. Node dissection is reserved for those patients with palpable adenopathy.

Heterotopic autotransplantation of parathyroid tissue in children undergoing total thyroidectomy.

AIM: The purpose of this study was to examine the efficacy of parathyroid autotransplantation in children undergoing total thyroidectomy. METHODS: We have prospectively evaluated 32 cases of total thyroidectomy in children. The ages ranged from 1 year to 15.7 years, and the mean was 8.9 years. In 31 cases, the indication for surgery was a diagnosis of MEN2A or 2B based on direct DNA testing. One child had suspected sporadic medullary thyroid carcinoma. All of the patients underwent heterotopic autotransplantation of parathyroid gland tissue. In 26 cases, the parathyroid tissue was placed in the nondominant forearm, while in 6 children it was autotransplanted into the sternocleidomastoid muscle. RESULTS: In 31 of 32 children (97%), the serum calcium level transiently decreased in the immediate postoperative period. All of the patients were placed on oral calcium carbonate and vitamin D supplementation, and the serum calcium levels became normal within several days. The supplemental medications were then weaned as tolerated. Within 3 months of their procedure, 30 patients (94%) had adequate parathyroid tissue engraftment, and the calcium and vitamin D medications were discontinued. One child required 9 months of calcium and vitamin D medications before she could be weaned from the medications. One child has been treated more recently, and is currently being weaned from supplemental calcium and vitamin D. Serum PTH levels in 22 patients who had placement of the tissue into their forearms were measured, and in each there was increased PTH in the grafted arm compared with the nongrafted arm. In five children who had parathyroid tissue grafted into the sternocleidomastoid muscle, the peripheral serum PTH levels were in the normal range. CONCLUSION: The heterotopic autotransplantation of resected parathyroid tissue is safe and effective in preventing permanent hypoparathyroidism.

Effects of growth hormone secretagogues in the transgenic growth-retarded (Tgr) rat.

Exogenous GH inhibits endogenous GH release by hypothalamic feedback. We have recently exploited this to generate transgenic growth-retarded (Tgr) rats, in which human GH is expressed in the hypothalamus, under the control of the rat GRF gene promoter. These rats show reduced pituitary size, GH deficiency, and dominant dwarfism, but are large enough for serial blood sampling studies to examine their spontaneous GH secretion and responses to GRF, somatostatin, and GH-releasing peptide-6 (GHRP-6). Like their normal wild-type littermates, Tgr rats show a sexually dimorphic pattern of GH secretion; males secrete GH in 3-h episodes, whereas females exhibit a more continuous irregular output, with higher baseline GH levels. In anesthetized male Tgr rats, the GH responses to GRF or GHRP-6 were markedly reduced compared with those of their nontransgenic littermates, but the differences were smaller in females. Despite the reduction in pituitary GH, peak plasma GH responses to serial GRF injections in conscious Tgr males or intermittent somatostatin infusions in conscious Tgr females were indistinguishable from the responses in their wild-type littermates. Furthermore, 7-day iv infusions of GRF (12.5-100 micrograms/day), given either continuously or as a pulsatile infusion stimulated growth in Tgr rats, as did pulsatile infusions of GHRP-6. Thus, despite their pituitary GH deficiency and dwarfism, Tgr rats maintain a sexually dimorphic pattern of GH release and can produce large GH secretory responses to exogenous secretagogues. They represent the first genetic model of GH deficiency in the rat in which dwarfism can be corrected by treatment with exogenous GH secretagogues.

Dominant dwarfism in transgenic rats by targeting human growth hormone (GH) expression to hypothalamic GH-releasing factor neurons.

Expression of human growth hormone (hGH) was targeted to growth hormone-releasing (GRF) neurons in the hypothalamus of transgenic rats. This induced dominant dwarfism by local feedback inhibition of GRF. One line, bearing a single copy of a GRF-hGH transgene, has been characterized in detail, and has been termed Tgr (for Transgenic growth-retarded). hGH was detected by immunocytochemistry in the brain, restricted to the median eminence of the hypothalamus. Low levels were also detected in the anterior pituitary gland by radioimmunoassay. Transgene expression in these sites was confirmed by RT-PCR. Tgr rats had reduced hypothalamic GRF and mRNA, in contrast to the increased GRF expression which accompanies GH deficiency in other dwarf rats. Endogenous GH mRNA, GH content, pituitary size and somatotroph cell number were also reduced significantly in Tgr rats. Pituitary adrenocorticotrophic hormone (ACTH) and thyroid-stimulating hormone (TSH) levels were normal, but prolactin content, mRNA levels and lactotroph cell numbers were also slightly reduced, probably due to feedback inhibition of prolactin by the lactogenic properties of the hGH transgene. This is the first dominant dwarf rat strain to be reported and will provide a valuable model for evaluating the effects of transgene expression on endogenous GH secretion, as well as the use of GH secretagogues for the treatment of dwarfism.

A study of the use of milk replacers for dairy calves in the United States.

This study focused on aspects of the National Dairy Heifer Evaluation Project that involved neonatal feeding practices and types of milk replacers utilized on dairy farms. Types of milk replacers and the management practices associated with their feeding were studied. Nearly 60% of US dairy farms use milk replacers for some or all of the feeding program for neonatal calves. Regional differences existed in the types of liquid feeds and milk replacers fed to calves. Western producers fed less milk replacer, and western and northeast producers fed replacers with less total CP. Many characteristics of management utilized along with these products reflect accepted management and nutrition practices. During the study period from 1991 to 1992, 11.2% of replacers contained casein. A greater proportion of these were found in the West during the first 6 mo of the study, reflecting changes in the milk replacer formulations during that time.

Latrodectus mactans (black widow spider) envenomation: an unusual cause for abdominal pain in pregnancy.

BACKGROUND: The differential diagnosis of abdominal pain in pregnancy is extensive. An important consideration in endemic areas is a bite by a black widow spider. CASE: A 30-year-old woman at 30 weeks' gestation presented with acute abdominal pain following an insect bite. We based the diagnosis on classic symptomatology in an area endemic for Latrodectus mactans. Treatment consisted of supportive therapy and observation. Symptoms resolved over 48 hours and did not recur. The patient delivered a healthy child at 40 weeks' gestation. CONCLUSION: In endemic areas, black widow spider envenomation should be part of the differential diagnosis of abdominal pain in pregnancy.