A Demonstration Project in New York and Virginia: Retrofitting Cost-Effective Roll-over Protective Structures (CROPS) on Tractors.

The NIOSH cost-effective roll-over protective structure (CROPS) demonstration project sought to determine whether three prototype roll-over protective structures (ROPS) designed to be retrofitted on Ford 8N, Ford 3000, Ford 4000, and Massey Ferguson 135 tractors could be installed in the field and whether they would be acceptable by the intended end users (farmers). There were a total of 50 CROPS. demonstrators (25 in New York and 25 in Virginia), with 45 observers attending the New York CROPS demonstrations and 36 observers attending the Virginia CROPS demonstrations, for a total of 70 participants in New York and 61 in Virginia. The oldest retrofitted tractors were 77 to 62 years old, while the newest retrofitted tractors were 40 to 37 years old. The most frequently retrofitted tractor in the CROPS demonstration project was a Ford 3000 series tractor (n = 19; 38%), followed by Ford 4000 (n = 11; 22%), Massey Ferguson 135 (n = 11; 22%), and Ford 8N (n = 9; 18%). A major issue of CROPS retrofitting was the rear wheel fenders. The effort involved in disassembling the fenders (removing the old bolts was often faster by cutting them with a torch), modifying the fender mounting brackets, and then reinstalling the fenders with the CROPS generally required the most time. In addition, various other semi-permanent equipment attachments, such as front-end loaders, required additional time and effort to fit with the CROPS. Demonstrators were asked to rank the reasons why they had not retrofitted their tractors with ROPS until they had enrolled in the CROPS demonstration program. ROPS "cost too much" was ranked as the primary reason for participants in both states (80% for New York and 88% for Virginia). The second highest ranked reasons were "ROPS wasn't available" for Virginia (80%) and "hassle to find ROPS" for New York (69%). The third highest ranked reasons were "not enough time to find ROPS" for New York (67%) and "hassle to find ROPS" for Virginia (79%). All demonstrators and observers indicated that they were glad to have participated in the CROPS project.

Adoption of rollover protective structures (ROPS) on U.S. farm tractors by state: 1993-1995, 2001, and 2004.

This research compares state-level rollover protective structure (ROPS) prevalence rates from the early and mid-1990s to those observed in the years 2001 and 2004. In addition, state-level ROPS prevalence rates are compared to state-level tractor overturn fatality rates. Tractor data for 1993-1995 and for 2001 and 2004 for all tractors and ROPS-equipped tractors in use on U.S. farms were derived from surveys conducted for NIOSH by the USDA-NASS. Changes in ROPS prevalence rates at the state level between the two time periods were assessed using a two-sample paired t-test with unequal sample sizes. Poisson regression was used to assess the association between ROPS prevalence rates and tractor overturn fatality rates at the state level. Overall, 49 of the 50 states had an observed increase in the percentage of farm tractors equipped with ROPS from 1993-1995 to 2001 and 2004. This increase was statistically significant for 34 states. Large shifts in ROPS prevalence were found within individual states and in clusters of states. These include a major increase in the southeastern U.S. and some western states. However, a core of states in the northeast (many of them in or near the Appalachian Mountains) through the upper midwest remain in the bottom quartile for ROPS prevalence. For the years 1992 through 2004, the highest fatality rates were observed in many of the same states that were identified previously as having persistently low ROPS prevalence rates. There is a clear relationship between low state-level ROPS prevalence rates and high state-specific tractor overturn fatality rates. While progress has been made in increasing the percentage of ROPS-equipped farm tractors, it is projected that ROPS prevalence rates will not reach a protective level nationally until after 2015. Regionally, the northeast and midwest will not reach protective levels of ROPS-equipped tractors until after 2020. Based on the adoption rates observed, tractor overturn rates will likely continue to be a more localized, but significant, public health issue for several states beyond the year 2020. The results of this study show the geographic areas of the U.S. where the greatest need exists, and where a greater emphasis should be placed on ROPS promotion activities. However, addressing this public health issue on a large scale will require resources and an organized commitment, which have historically been lacking.

Effect of method of application of a fibrolytic enzyme product on digestive processes and milk production in Holstein-Friesian cows.

Four multiparous cows with cannulas in the rumen and proximal duodenum were used in early lactation in a 4 x 4 Latin square experiment to investigate the effect of method of application of a fibrolytic enzyme product on digestive processes and milk production. The cows were given ad libitum a total mixed ration (TMR) composed of 57% (dry matter basis) forage (3:1 corn silage:grass silage) and 43% concentrates. The TMR contained (g/kg dry matter): 274 neutral detergent fiber, 295 starch, 180 crude protein. Treatments were TMR alone or TMR with the enzyme product added (2 kg/1000 kg TMR dry matter) either sprayed on the TMR 1 h before the morning feed (TMR-E), sprayed only on the concentrate the day before feeding (Concs-E), or infused into the rumen for 14 h/d (Rumen-E). There was no significant effect on either feed intake or milk yield but both were highest on TMR-E. Rumen digestibility of dry matter, organic matter, and starch was unaffected by the enzyme. Digestibility of NDF was lowest on TMR-E in the rumen but highest postruminally. Total tract digestibility was highest on TMR-E for dry matter, organic matter, and starch but treatment differences were nonsignificant for neutral detergent fiber. Corn silage stover retention time in the rumen was reduced by all enzyme treatments but postruminal transit time was increased so the decline in total tract retention time with enzymes was not significant. It is suggested that the tendency for enzymes to reduce particle retention time in the rumen may, by reducing the time available for fibrolysis to occur, at least partly explain the variability in the reported responses to enzyme treatment.

Effect of feeding supplemental fibrolytic enzymes or soluble sugars with malic acid on milk production.

Two trials were conducted to evaluate effects of feeding supplemental fibrolytic enzymes or soluble sugars and malic acid on milk production. In trial 1, 257 cows at four sites were fed a basal diet consisting of no more than 60% of forage DM as corn silage and less than 40% as alfalfa hay. Cows were assigned randomly within site, parity, and two stages of lactation to: 1) control; 2) enzyme A; 3) enzyme B; and 4) soluble sugars and malic acid. There was a 14-d pretreatment and an 84-d treatment period. Enzyme solutions were sprayed on either the forage component or the TMR each day while mixing feed. Trial 2 was similar, except 122 cows at one site in the United Kingdom were fed diets containing forage that was 75% corn silage and 25% grass silage, and all cows began the study between 25 to 31 DIM. Mean milk productions for 233 cows that completed trial 1 were 32.9, 32.5, 32.4, and 32.9 kg/d for control, enzyme A, enzyme B, and soluble sugars and malic acid, respectively. Mean milk productions for 116 cows that completed trial 2 were 28.2, 27.9, 28.8, and 28.4 kg/d, respectively. In vitro analyses of the activities of enzyme solutions indicated that all major cellulose and hemicellulose degrading activities were present; however, the pH optima (approximate pH = 4 to 5) were more acidic, and the temperature optimum (approximately 50 degrees C) was greater than normal pH and temperature in the rumen. If fibrolytic activity in the rumen is a major mechanism of action of supplemental fibrolytic enzymes, it appears that considerable activity of these preparations was lost due to conditions in the rumen. In conclusion, feeding supplemental fibrolytic enzymes or malic acid with soluble sugars had no effect on milk production under the conditions used in this study.

Traumatic injuries in agriculture.

The National Coalition for Agricultural Safety and Health (NCASH) in 1988 addressed issues in agriculture and noted "a sense of urgency... arose from the recognition of the unabating epidemic of traumatic death and injury in American farming . . ." This article provides an update to the NCASH conference on traumatic injuries in agriculture, a history on how the facts and figures were arrived at for the NCASH conference, and a current report on the status of traumatic injuries in agriculture in the U.S. Fatal and nonfatal injuries are addressed along with national and regional surveillance systems. The Census of Fatal Occupational Injuries (CFOI) was used for reporting national agricultural production fatal injuries from 1992-1998 (25.8 deaths per 100,000 workers), the Traumatic Injury Surveillance of Farmers (TISF) 1993-1995 was used to report nonfatal injuries occurring nationally (7.5/100 workers), and Regional Rural Injury Studies I and II (RRIS-I and RRIS-II) were used to illustrate a regional approach along with in-depth, specific analyses. Fatality rates, which showed some decline in the 1980s, were fairly constant during the 1990s. Changes in nonfatal injury rates for this sector could not be assessed due to a lack of benchmark data. The main concerns identified in the 1989 NCASH report continue today: tractors are the leading cause of farm-related death due mostly to overturns; older farmers continue to be at the highest risk for farm fatalities; and traumatic injuries continue to be a major concern for youth living or working on U.S. farms. Fatal and nonfatal traumatic injuries associated with agricultural production are a major public health problem that needs to be addressed through comprehensive approaches that include further delineation of the problem, particularly in children and older adults, and identification of specific risk factors through analytic efforts. Continued development of relevant surveillance systems and implementation of appropriate interventions are the primary challenges for the current decade.

Evaluation of the effectiveness of educational interventions in the Pennsylvania Central Region Farm Safety Pilot Project.

BACKGROUND: Evaluation of agricultural safety interventions has frequently been identified as an area requiring further research. This study prospectively evaluates the effectiveness of three specific educational safety interventions in reducing farm hazards. METHODS: Farm characteristics and hazard conditions at 216 farms in Pennsylvania were assessed through a questionnaire and objective audit, respectively, at both pre- and post-intervention time points. Counties were assigned to one of the following interventions: youth education, community coalition, self-audit, pre/post control, or post-only control group. Changes in hazard were analyzed through linear regression. RESULTS: Self-audit was the most effective intervention, leading to a 20% reduction in hazard scores. The community coalition and pre/post control group also showed reductions. CONCLUSIONS: Intervention effectiveness significantly differed depending on initial hazards, indicating the need to target specific interventions for more or less hazardous farms. Findings of this prospective evaluation differed from the initial cross-sectional results, thus underscoring the need for longitudinal investigations.

Secretion of dopamine and norepinephrine in hypophyseal portal blood and prolactin in peripheral blood of Holstein cattle.

The objective was to test the hypothesis that dopamine regulates prolactin (PRL) secretion by determining acute changes in catecholamine concentrations in hypophyseal portal blood of cattle, and their relation to peripheral blood concentration of PRL in hypophyseal stalk-transected (HST) and sham-operated controls (SOC). Holstein heifers (606 +/- 21 kg BW; mean +/- SE) were subjected to neurosurgery for 8 h to collect hypophyseal portal blood with a stainless steel cannula designed with a cuff placed under the pituitary stalk and peripheral blood via a jugular vein catheter. PRL plasma concentration was measured by radioimmunoassay, and dopamine and norepinephrine in portal plasma by radioenzymatic assay. During anesthesia before HST or SOC, PRL plasma concentration ranged from 20-40 ng/ml throughout 255 min. PRL abruptly increased and remained above 90 ng/ml after HST compared with a steady decrease to <20 ng/ml in SOC heifers throughout 440 min. Within 5 min after severing the hypophyseal stalk, dopamine in portal blood (>8 ng/ml) was significantly increased (P < 0.05) compared with peripheral blood (<2 ng/ml). Norepinephrine concentration in portal blood was significantly greater (P < 0.05) than in peripheral blood during the first 60 min. The sustained high PRL level in peripheral plasma after severing the hypophyseal stalk stimulated hypothalamic dopamine secretion from hypophyseal portal vessels during the prolonged period of blood collection. Norepinephrine concentration in these cattle was greater in hypophyseal portal than in peripheral blood, implicating both an important hypothalamic source of the catecholamine as well as an adrenal gland contribution during anesthesia.

Pregnancy, parturition, and lactation in hypophyseal stalk-transected beef heifers.

Progesterone secretion is crucial for maintaining pregnancy to parturition in mammalian species, and in cattle the corpus luteum is the primary source of this hormone. This study determined the roles of prolactin (PRL), growth hormone (GH) and luteinizing hormone (LH) in the luteotropic process in beef heifers hypophyseal stalk-transected (HST, n=7) or sham operated (sham operated controls, SOC, n=9) during midgestation. The main finding was that endogenous PRL and GH maintained progesterone secretion in HST heifers in a similar manner to that in SOC throughout pregnancy. Serum PRL averaged 37 vs 187 and GH 2 vs 4 ng/ml in HST heifers compared with SOC, whereas LH abruptly decreased to undetectable levels after HST compared with a modest 0.4 ng/ml in SOC heifers. The second finding was that parturition and lactation occurred in HST heifers with calf delivery induced to occur at the same time as SOC. Milk production in HST animals was severely limited, and postpartum estrus obliterated compared with SOC. The suckling stimulus sustained milk ejection in HST heifers in spite of diminished PRL, GH, thyroid stimulating hormone, thyroxine and tri-iodothyronine secretion. The results suggest that PRL, GH and possibly placental lactogen are luteotropic during pregnancy in cattle.

Effect of recombinant bovine somatotropin on milk production and composition of cows with Streptococcus uberis mastitis.

The protective effect of bovine somatotropin (bST) during experimental Streptococcus uberis mastitis in cows was studied. The left quarters of 10 cows were infected with 500 cfu of S. uberis O140J. Five cows were subcutaneously treated with 500 mg of recombinant bST 7 d before and after infection, and 5 control cows received the excipient. In the treated cows, total milk production significantly increased after the first and second bST treatments. After infection, milk production decreased 24 and 40% in the infected quarters, 6 and 14% in the uninfected quarters, and 15 and 28% overall for treated and control cows, respectively. In the bST group, milk production was completely restored after 3 wk, but, in the control group, total production and the production of the infected quarters remained lower than preinfection production. The increase in somatic cell count occurred earlier and more rapidly in the control group, and the return to normal values was also more rapid in these cows. The amount of bacteria in milk was higher in the control cows. Changes in milk composition, such as lactose, protein, fat, Na+, K+, and Cl-, were significantly more pronounced in the control cows. Also, clinical symptoms were more prominent in the control cows. Somatotropin protected the mammary gland from excessive production losses and compositional changes during a subsequent episode of experimentally induced Streptococcus uberis mastitis and significantly improved the normalization of production and composition, which indicates a beneficial effect on the restoration of the integrity of the blood-milk barrier.

Effect of bovine somatotropin on neutrophil functions and clinical symptoms during Streptococcus uberis mastitis.

The effect of recombinant bovine somatotropin (bST) on the chemiluminescence, diapedesis, and expression of adhesion receptors (CD11a, CD11b, CD18) of isolated polymorphonuclear leukocytes was studied. The plasma concentrations of insulin-like growth factor-I (IGF-I), bST, cortisol, and alpha-lactalbumin were also monitored. In addition, general and local clinical symptoms and the differentiation of circulating leukocytes were also studied during experimentally induced Streptococcus uberis mastitis in cows. Ten cows were infected with 500 cfu of S. uberis O140J in both left quarters. Five cows were subcutaneously treated with 500 mg of recombinant bST 7 d before and after infection, and 5 control cows received the excipient. General (fever, tachycardia, inappetance, and depression) and local symptoms (swelling, pain, firmness, and flecks in milk) were more acute, severe, and longer-lasting in control cows. Treatment with bST had no effect on chemiluminescence and diapedesis of circulating polymorphonuclear leukocytes and no effect on the expression of adhesion receptors. Recombinant bST induced significantly higher IGF-I and bST concentrations in plasma. The leukopenia observed after infection was less pronounced in the bST-treated cows, and the number of circulating band neutrophils and metamyelocytes was significantly lower in the treated group. The concentration of cortisol did not differ between both groups, but the blood concentration of alpha-lactalbumin significantly increased in both groups from 6 d after infection. These results showed that treatment with recombinant bST improves animal welfare by protecting the cows from severe local and general clinical symptoms during subsequent S. uberis mastitis, but that it has no effect on chemiluminescence, diapedesis, and the expression of adhesion receptors of circulating polymorphonuclear leukocytes.

Long-term growth after hypophyseal stalk transection and hypophysectomy of beef calves.

Hypothalamic hormones regulate episodic and basal secretion of hormones from the anterior pituitary gland that affect metabolism and growth in cattle. This study focused on long-term growth in young calves subjected to hypophysectomy (HYPOX), hypophyseal stalk transection (HST), and sham operation control (SOC). Cross-bred (Hereford x Aberdeen Angus) and Hereford, and Aberdeen Angus calves were HYPOX (n = 5), HST (n = 5), or SOC (n = 8) at 146 +/- 2 days of age, whereas another group was HST (n = 5) or SOC (n = 7) at 273 +/- 5 days of age. Body weight was determined every 21 days from birth to 1008 days of age. Anterior vena cava blood was withdrawn at 4-day intervals from day 64-360 for RIA of GH, TSH, T4, T3, and LH, and at 20-min intervals for 480 min to determine episodic hormone secretion. Daily feed intake was determined in HST and SOC calves during an 80-day period. Birth weight averaged 35 +/- 1 kg (+/- SE) and was 142 +/- 4 kg at 126 days and 208 +/- 8 kg at 252 days before surgery. From day 146-1008, growth was arrested (P < 0.001) in HYPOX (0.06 +/- 0.01 kg/day) compared with SOC (0.50 +/- 0.04 kg/day) calves. Growth continued but at a significantly lower rate (P < 0.05) in calves HST at 146 days (0.32 +/- 0.07 kg/day) and 273 days (0.32 +/- 0.06 kg/day) compared with SOC (0.50 +/- 0.09 kg/day). Growth continued to be impaired to 1008 days, but more so in those HST at 146 days (432 +/- 43 kg BW) than 273 days (472 +/- 5 kg BW) and less (P < 0.05) than SOC (586 +/- 37 kg BW). Daily feed intake was consistently less (P < 0.05) in HST compared with SOC calves. Although episodic GH secretion was abolished and peripheral serum GH concentration remained consistently lower in HST (2.4 ng/ml) than SOC (5.5 ng/ml; P < 0.01), the calves continued to grow throughout 1008 days. Peripheral serum TSH concentration was less (P < 0.05) HST compared with SOC calves. There was an abrupt decrease (P < 0.001) in serum T4 (4-fold) and T3 (3-fold) concentration after surgery that remained to 360 days in HST compared with SOC calves. At the time calves were killed, pituitary gland weight was markedly reduced (P < 0.001) in HST (0.18 +/- 0.01 g/100 kg BW) compared with SOC (0.54 +/- 0.03 g/100 kg BW). Histological examination of pituitary glands from HST calves indicated the persistence of secretory GH and TSH cells in the same areas of the adenohypophysis as SOC calves. Coronal sections of the gland stained with performic acid-Alcian blue-periodic acid-Schiff-orange G, revealed GH and TSH secreting cells in HST calves similar to controls. These results indicate that long-term growth continues, but at a slower rate, after hypophyseal stalk transection of immature calves in spite of complete abolition of episodic GH secretion and consistently decreased basal secretion of GH, TSH, T4, and T3 compared with sham-operated animals. Growth was abolished after hypophysectomy of immature calves in which circulating GH and TSH was undetectable.

Seasonal regulation of prolactin secretion in hypophyseal stalk transected beef calves.

Seasonal regulation of prolactin secretion was investigated in crossbred beef heifer calves. Calves were randomly assigned to hypophyseal stalk transection (HST, n = 6) or sham-operation control (SOC, n = 6) groups and fitted 1 day before surgery with an indwelling external jugular catheter. Prolactin (PRL), growth hormone (GH), thyroid stimulating hormone (TSH), thyroxine (T4), and tri-iodothyronine (T3) in peripheral serum were measured by radioimmunoassay in samples obtained before and after HST or SOC. During the first 8 days after HST, PRL concentrations remained significantly greater than SOC, but then decreased in both HST and SOC calves to 4 +/- 2 (+/- SE) and 10 +/- 3 ng/ml, respectively (P < 0.001). PRL remained low in both HST and SOC groups for three months after surgery. By four months, HST calves had lower basal PRL (5 +/- 1 ng/ml) than observed in SOC (40 +/- 4 ng/ml), and seasonal changes in PRL blood concentration also were attenuated by HST. Although HST reduced PRL secretion, it did not abolish the effect of seasonal changes (P < 0.01); circulating PRL concentration increased six-fold by shifts in photoperiod and temperature from winter to summer in these stalk-transected calves. The SOC group had higher serum GH during the winter (3.8 +/- 0.8) than in July (1.3 +/- 0.03 ng/ml). The HST group had the opposite profile of GH concentration, however, with concentrations being higher during May through July. Thyroid stimulating hormone secretion was partly sustained after stalk transection possibly by negative feedback of reduced circulating thyroxine and tri-iodothyronine. These results in both hypophyseal stalk-transected and sham-operated beef calves maintained in a natural environment strongly suggest that hypothalamic regulation of PRL secretion by adenohypophyseal cells is extremely sensitive to seasonal changes throughout the year. Additionally, immediately after HST, PRL blood concentration remains significantly greater than in SOC calves but eventually decreases to low blood concentration in HST calves, and unlike that seen after HST in primates. Regardless, basal PRL serum concentration responds to seasonal changes, but a less distinct change in basal GH serum concentration in HST calves than seen in the SOC calves.

The effect of bovine somatotropin and diet on somatotropin binding sites in hepatic tissue of lactating dairy cows.

In the lactating cow, galactopoiesis is stimulated by treatment with recombinant bovine somatotropin (bST) and by an improved plane of nutrition. The present study determined the interaction between these variables and examined whether a positive galactopoietic effect was accompanied by a change in hepatic binding sites for bST. Lactating dairy cows received one of three diets with increasing nutrient density; diet 1, 150 g/kg of dry matter (DM) of crude protein (CP) and 10.5 MJ/kg of DM of metabolizable energy; diet 2, 170 g/kg of DM of CP and 11.3 MJ/kg of DM of metabolizable energy; and diet 3, 190 g/kg of DM of CP and 12.1 MJ/kg of DM of metabolizable energy. At 90 d after calving, half of the cows in each dietary group were treated with bST every 14 d for the rest of the lactation. Both nutrient density and administration of bST increased milk yield significantly in mid and late lactation; there was no significant treatment by diet interaction. Treatment with bST significantly increased plasma concentrations of insulin-like growth factor (IGF)-I compared with IGF-I concentrations in controls in both mid and late lactation. Comparisons within diet revealed that concentrations of IGF-I were significantly higher in cows fed diet 3 than in cows fed diets 1 and 2 at both stages of lactation. Increases in plasma insulin were confined to cows in late lactation, and no changes were observed for nonesterified fatty acids. Liver biopsies showed that concentrations of hepatic binding sites for bST were not affected significantly by bST treatment but were increased in midlactation for cows fed diet 3. Concentration of hepatic binding sites per unit weight of tissue were greater for cows in midlactation than for cows in late lactation. In summary, exogenous bST treatment and increased nutrient density were associated with elevated plasma IGF-I concentrations and increased milk yield; however, only nutrient density in midlactation increased the number of hepatic binding sites for bST. Exogenous bST treatment had relatively little effect on the concentration of hepatic bST receptors compared with nutrient density.

Use of bovine somatotropin in the tropics: the effect of sometribove on milk production in western, eastern, and southern Africa.

Seven field studies conducted in western, eastern, and southern Africa to determine the effect of a prolonged-release formulation of bovine somatotropin (bST) administered at 14-d intervals on milk production of indigenous, crossbred, and purebred cows are described. Studies in Gambia showed that 334 mg of a prolonged-release formulation of bST increased milk production of N'Dama cattle by 205 ml/d, which represented a 22% increase in milk production, and increased the body weight gain of calves. In small dairy units in Zimbabwe, 500 mg of a prolonged-release formulation of bST increased milk production of crossbreds from 8.0 to 10.0 kg/d. Milk production response of crossbred cows in Kenya increased 2.5 kg/d after the lower dose rate (334 mg); no further increases were observed when the dose rate was increased to 500 mg. A study with Holsteins showed that delaying treatment of 500 mg of a prolonged-release formulation of bST from 90 to 120 or 150 d postpartum resulted in similar milk production responses of 3.5, 3.4, and 3.2 kg/d, respectively. The milk production response (6.1 kg/d) recorded in another study with Holsteins was attributed to an excellent plane of nutrition and delayed treatment initiation. For nonpregnant cows that were classified to be culled, the prolonged-release formulation of bST was efficacious and could potentially be used to extend lactation.

Pituitary response to thyrotropin, corticotropin, and gonadotropin-releasing hormones in lactating cows treated with sometribove for a fourth consecutive lactation.

The effect of chronic treatment with recombinant methionyl bovine somatotropin (USAN, sometribove) on anterior pituitary secretions and its target organs was investigated in six control and six sometribove-treated British Friesian cows. Cows averaged 112 and 119 d postpartum in their fourth lactation of treatment and, except for one control, had active corpora lutea. During each lactation, treated cows received sometribove injections (500 mg) every 2 wk (injection cycle) starting 60 +/- 3 d postpartum. On Day 9 of one injection cycle, blood was sampled for 390 min, starting 30 min before an intravenous injection of thyrotropin (TRH, 0.33 microgram/kg), corticotropin (100 microgram), and gonadotropin (GnRH, 200 micrograms)-releasing hormones. Baseline somatotropin (bST) and adrenocorticotropin (ACTH) were higher in sometribove-treated cows vs. controls (3.27 vs. 1.03 ng/ml and 35.24 vs. 19.28 pg/ml, respectively). Baseline total thyroxine, free thyroxine, triiodothyronine, prolactin, follicle stimulating and luteinizing hormones, estradiol, and progesterone (P4) were similar across treatments. Circulating cortisol levels did not differ between control and sometribove cows, indicating a reduced adrenal ACTH responsiveness in the latter. Releasing factors induced similar changes across treatments in hormones studied with the following exceptions: a bST spike was seen in control cows only, cortisol response to ACTH was reduced in treated cows, and a significantly higher P4 concentration was detected in the plasma of sometribove-treated cows, suggesting increased ovarian responsiveness to GnRH-stimulated P4 output. The study demonstrated reduced bST response to TRH, consistent with physiologic feedback mechanisms, whereas the release profiles of the other pituitary hormones were unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)

Work-related fatalities in the agricultural production and services sectors, 1980-1989.

A total of 6,727 workers died of work-related injuries in the agricultural production and agricultural services sectors between 1980 and 1989, as established by data from the National Institute for Occupational Safety and Health (NIOSH) National Traumatic Occupational Fatalities (NTOF) surveillance system. The agricultural production sector accounted for the higher fatality rate (22.9 deaths per 100,000 workers), due largely to deaths caused by machinery and motor vehicles. The leading cause of death in the agricultural services sector was being struck by falling objects, primarily trees. Fatality rates were highest in the East South Central United States and lowest in the New England states. Blacks had the highest fatality rate (26.4 deaths per 100,000 workers) while workers other than white or black had the lowest rate (18.9 per 100,000 workers). Males were at higher risk of death than females, with the 65 years of age and older male group having the highest rate (60.5 deaths per 100,000 workers). Males 16-24 years of age exhibited the largest decrease in their average annual fatality rate during the 10-year period, down to 7.2 from 20.6 deaths per 100,000 workers. Possible reasons for this decrease are suggested.

Clinical mastitis in cows treated with sometribove (recombinant bovine somatotropin) and its relationship to milk yield.

Effect of sometribove (methionyl bovine somatotropin) on mastitis in 15 full lactation trials (914 cows) in Europe and the US and 70 short-term studies (2697 cows) in eight countries was investigated. In full lactation studies, sometribove (500 mg/2 wk) was given for 252 d, commencing 60 d postpartum. Although herds varied considerably, incidence of clinical mastitis within a herd was similar for cows receiving control and sometribove treatments. Relative risk analyses indicated no treatment effect, and percentage of mastitis during treatment was similar for control and sometribove groups. A positive linear relationship existed between peak milk yield and mastitis incidence (percentage of cows contracting mastitis or cases per 100 cow days); sometribove treatment did not alter this relationship. Increases in mastitis related to milk yield increase from sometribove or related to genetic selection were similar. When expressed per unit of milk, mastitis incidence declined slightly as milk yield increased; this relationship was not altered by sometribove. No effect on clinical mastitis was observed in 70 commercial herds utilizing sometribove for 84 d. However, effects were significant for stage of lactation and milk yield. Overall, studies represented a wide range of research and commercial situations demonstrating that sometribove had no effect on incidence of clinical mastitis during the lactation of treatment. Furthermore, sometribove did not alter typical relationships between milk yield or herd factors and incidence of clinical mastitis.

Long-term effects of sometribove in lactating cows during a fourth consecutive lactation of treatment: insulin and somatotropin responses to glucose infusion.

The effect of sometribove (USAN, methionyl bST) on the endocrine pancreas and blood bST concentrations was investigated in 6 control and 6 treated Friesian cows, averaging 111 and 118 d postpartum in their fourth lactation of treatment. Each lactation the treated cows received sometribove injections (500 mg) every 2 wk (injection cycle) starting 60 +/- 3 d postpartum, increasing milk yield 3.3, 5.9, 1.9, and 4.2 kg/d in lactations 1, 2, 3, and 4, respectively. On d 8 of a fourth lactation injection cycle, blood was sampled for 390 min, starting 30 min before an intravenous glucose infusion (100 mg/kg) over a 20-min period. Preinfusion concentrations of glucose, insulin, and bST were elevated in sometribove-treated cows versus controls: 82.1 versus 74.4 mg/dl, 28.1 versus 19.7 microIU/ml, and 4.6 versus .9 ng/ml, respectively. Glucose infusion resulted in a rapid increase in blood glucose and insulin concentrations, followed by a sharp decline to preinfusion values across both treatments, resulting in similar net area under the curves for glucose and insulin. Blood bST concentrations remained unchanged. This study supports the concept that sometribove increases milk yield in dairy cows by chronically influencing homeorhetic mechanisms.