Attractant and disruptant semiochemicals for Dendroctonus jeffreyi (Coleoptera: Curculionidae: Scolytinae).

Jeffrey pine, Pinus jeffreyi Greville and Balfour, is a dominant yellow pine and important overstory component of forests growing on diverse sites from southwestern Oregon to Baja California to western Nevada. The Jeffrey pine beetle, Dendroctonus jeffreyi Hopkins (Coleoptera: Curculionidae: Scolytinae), is monophagous on Jeffrey pine and its primary insect pest. Despite the importance of P. jeffreyi, difficult terrain, environmental concerns, and lack of roads can constrain pest management activities. Semiochemicals are often easier to apply and more environmentally acceptable than other options, but they are lacking in this system. Attractants have been identified, but field bioassays have been limited because of infrequent or short duration outbreaks and a lack of beetles during nonoutbreak periods. Disruptant semiochemicals have not been assessed for D. jeffreyi during outbreak conditions; however, commercially available semiochemicals have been implicated as disruptants for this bark beetle. The objective of this study was to identify the most effective commercially available attractant and disruptant semiochemicals for D. jeffreyi. Our highest observed catch occurred with the blend of 5% 1-heptanol and 95% n-heptane. When this was used to challenge potential disruptant semiochemicals, the combination of S-(-)-verbenone and the green leaf volatile blend (cis-3-Hexenol and 1-Hexanol) reduced trap catch by ≍80%. However, frontalin was most effective, reducing the number of D. jeffreyi caught by >96%. Within each year of the study, the percentage female of D. jeffreyi caught with our attractant decreased from start to end of the experimental period. On average, our first collection in a year (mid-June to early July) was 59% female, whereas our last (mid-August) was 34%. Frontalin was equally or more effective against females (the pioneering sex) than males, providing optimism that semiochemical disruption may be possible for protecting Jeffrey pines from D. jeffreyi.

Estimating viral titres in solutions with low viral loads.

An important consideration in the manufacture of products derived from animal or human sources is the virus reduction capacity of the manufacturing process as estimated using validated bench-scale models of relevant manufacturing steps. In these studies, manufacturing process intermediates are spiked with virus and processed using the bench-scale model and the resulting viral titres of input and output samples are typically determined using cell-based infectivity assays. In these assays, the Spearman-Kärber (SK) method is commonly used to estimate titres when there is one or more positive observation (i.e., the presence of any viral cytopathic effect). The SK method is most accurate when the proportion of positive observations ranges from <0.1 to >0.9 across dilutions but can be biased otherwise. Maximum likelihood (ML) based on a single-hit Poisson model is an alternative widely used estimation method. We compared SK with ML and found the methods to have similar properties except for situations in which the concentration of virus is low but measurable. In this case, the SK method produces upwardly biased estimates of titres. Based on our results, we recommend the use of either ML or SK at most virus concentrations; however, at low virus concentrations ML is preferred.

The addition of cottonseed hulls to the starter and supplementation of live yeast or mannanoligosaccharide in the milk for young calves.

The objectives of this study were to investigate the effects of the addition of cottonseed hulls (CSH) to the starter and the supplementation of live yeast product (YST) or mannanoligosaccharide product (MOS) to milk, on growth, intake, rumen development, and health parameters in young calves. Holstein (n = 116) and Jersey (n = 46) bull (n = 74) and heifer (n = 88) calves were assigned randomly within sex at birth to treatments. All calves were fed 3.8 L of colostrum daily for the first 2 d. Holstein calves were fed 3.8 L of whole milk, and Jersey calves were fed 2.8 L of whole milk through weaning at 42 d. Calves continued on trial through 63 d. Six treatments were arranged as a 2 x 3 factorial. Calves received either a corn-soybean meal-based starter (21% crude protein and 6% acid detergent fiber; -CSH) or a blend of 85% corn-soybean meal-based starter and 15% CSH (18% crude protein and 14% acid detergent fiber; +CSH) ad libitum. In addition, calves received whole milk with either no supplement (NONE) or supplemented with 3 g/d of mannanoligosaccharide product (MOS) or 4 g/d of live yeast product (YST) through weaning at 42 d. Twelve Holstein steers [n = 6 (per starter type); n = 4 (per supplement type)] were euthanized for collection and examination of rumen tissue samples. Dry matter intake (DMI) was greater for Holstein calves fed +CSH (0.90 kg/d) than -CSH (0.76 kg/d). Final body weight at 63 d of Holstein calves fed +CSH (75.8 kg) was greater than that of those fed -CSH (71.0 kg). Average daily gain (ADG) was greater for Holstein calves fed +CSH (0.58 kg/d) than -CSH (0.52 kg/d). However, Holstein calves fed -CSH had a greater feed efficiency (FE; 0.71 kg of ADG/kg of DMI) than those fed +CSH (0.65 kg of ADG/kg of DMI). Also, Holstein calves fed +CSH had narrower rumen papillae (0.32 mm) compared with those fed -CSH (0.41 mm). There were no significant effects of CSH on DMI, ADG, or FE in Jersey calves. There were no significant effects of YST or MOS on DMI, ADG, FE, or rumen papillae measures in Holstein calves. Jersey calves fed YST or MOS had greater final body weight at 63 d (51.2 kg and 51.0 kg, respectively) than calves fed NONE (47.5 kg). However, there were no significant effects of YST or MOS on DMI, ADG, or FE in Jersey calves.

Supplementing limited methionine diets with rumen-protected methionine, betaine, and choline in early lactation Holstein cows.

Eighty lactating Holstein cows from 21 to 91 d in milk were fed a corn silage-based total mixed ration (TMR) formulated with the Met content limited (42 g/ d) to investigate the impact of supplementing rumen-protected (RP) forms of Met, betaine, and choline on performance and metabolism. One of 4 supplements was blended into the TMR to produce 4 dietary treatments: 1) control, 2) 20 g/d of RP-Met, 3) 45 g/d of RP-betaine, and 4) 40 g/d of RP-choline. Calcium salts of fatty acids were used to protect both RP-betaine and RP-choline supplements. A similar amount of Ca salts of fatty acids was included in both control and RP-Met supplements to provide equal amounts of fat to all treatments. Overall, no differences in intake, milk yield, or milk composition were observed in primiparous cows. Average dry matter intake, body weight, and body condition score were not different among treatments in multiparous cows. Milk yield was higher in multiparous cows fed RP-choline compared with the other treatments. Multiparous cows fed RP-choline had higher milk protein yield than cows fed control or RP-betaine but was not different from cows fed RP-Met. Multiparous cows fed RP-choline had higher milk fat yield than cows fed RP-Met but was not different from cows fed control or RP-betaine. There were no beneficial effects of RP-betaine supplementation to a Met-limited TMR.

Lactoferrin supplementation to Holstein calves during the preweaning and postweaning phases.

Sixty Holstein calves (30 bulls, 30 heifers) were used to examine the effects of supplemental lactoferrin on feed intake, growth, and health during the preweaning and postweaning periods. One of 3 levels of lactoferrin was supplemented from 3 to 56 d in either whole milk or water to produce 3 dietary treatments: 1) 0 g/d, 2) 0.5 g/d, and 3) 1 g/d. Whole milk (3.8 L/d) containing lactoferrin supplements was fed from bottles until weaning at 35 d. From d 36 to 56, lactoferrin supplements were added to water (15 to 25 mL) and fed from bottles. Lactoferrin supplementation had no effect on feed intake, body weight, average daily gain, heart girth, body temperature, fecal scores, respiratory scores, or haptoglobin concentrations. Calves were housed in individual pens in either an open-sided barn or hutches. Calves raised in the barn consumed more calf starter and therefore grew better than calves raised in hutches. Under the conditions of this study, lactoferrin supplementation was not beneficial. Further research is needed to fully elucidate the role of lactoferrin, and possible benefits during different feeding conditions or milk sources.

Genetics of sex pheromone blend differences between Heliothis virescens and Heliothis subflexa: a chromosome mapping approach.

Males of the noctuid moths, Heliothis virescens and H. subflexa locate mates based on species-specific responses to female-emitted pheromones that are composed of distinct blends of volatile compounds. We conducted genetic crosses between these two species and used AFLP marker-based mapping of backcross families (H. subflexa direction) to determine which of the 30 autosomes in these moths contained quantitative trait loci (QTL) controlling the proportion of specific chemical components in the pheromone blends. Presence/absence of single H. virescens chromosomes accounted for 7-34% of the phenotypic variation among backcross females in seven pheromone components. For a set of three similar 16-carbon acetates, two H. virescens chromosomes interacted in determining their relative amounts within the pheromone gland and together accounted for 53% of the phenotypic variance. Our results are discussed relative to theories about population genetic processes and biochemical mechanisms involved in the evolution of new sexual communication systems.

Technical note: technique for dissection and analysis of the rumen in young calves.

This paper discusses a technique used to evaluate rumen development in young calves, including removal, dissection, and analysis of tissue. The method allowed for examination of the different sacs of the rumen (dorsal, ventral, cranial, and caudal) using scanning electron microscopy to measure papillae denseness and histology slides to measure papillae length and width. Computer software was used to produce accurate measurements of papillae. The rumens of young calves were dissected, and samples were taken from the cranial, caudal, ventral, and dorsal sections. Calves were part of a nutrition research study, and dietary treatments did have an effect on development measurements such as length, width, and papillae denseness.

Effects of amounts and degradability of dietary protein on lactation, nitrogen utilization, and excretion in early lactation Holstein cows.

Five treatment diets varying in crude protein (CP) and rumen undegradable protein (RUP) were calculated to supply a postruminal lysine to methionine ratio of about 3:1. Diets were fed as a total mixed ration to 65 Holstein cows that were either primiparous (n = 28) or multiparous (n = 37) from 21 to 120 d in milk to determine effects on lactation and nitrogen utilization. Crude protein % and calculated RUP (% of CP) of diets [on a dry matter (DM) basis] were: 1) 19.4, 40 (HPMU), 2) 16.5, 34 (LPLU), 3) 16.8, 40 (LPMU), 4) 16.8, 46 (LPHU), 5) 17.2, 43 (LPHU + UREA), which is the result of adding 0.4% of the diet DM as urea to LPHU. The corn silage-based treatment diets contained an average of 24% acid detergent fiber and 1.6 Mcal/kg net energy of lactation. Milk urea nitrogen (MUN) concentrations and body weights (BW) were used to calculate predicted amounts of urinary nitrogen (N) using the relationship: urinary N (g/d) = 0.0259 x BW (kg) x MUN (mg/dl). Cows fed HPMU had greater CP and RUP intakes, which resulted in higher concentrations of plasma urea nitrogen, rumen ammonia, MUN, and predicted urinary N. Milk yield, fat yield, fat percent, protein yield, and protein percent were not significantly different among treatments. Parity primarily affected parameters that were related to body size and not measurements of N utilization. The interaction of treatment and parity was not significant for any measurements taken. In this study, cows fed LPHU had significantly lower MUN and predicted urinary N without limiting production. These results demonstrate the potential to optimize milk production while minimizing N excretion in lactating dairy cattle.

Lack of teratogenicity of microcystin-LR in the mouse and toad.

Microcystin-LR (MC-LR) is a cyanobacterial toxin generated by the organism Microcystis aeruginosa. Although the hepatotoxicity of this chemical has been characterized, the potential developmental toxicity in vertebrates has not been well studied. The purpose of this study was to elucidate the effects of this toxin on the in vivo and in vitro development of mammals and the development of an Anuran (toad). Initial acute toxicity experiments with female CD-1 mice were accomplished with MC-LR administered i.p. in saline. Lethality occurred at 128 and 160 microg kg (-1) and histopathology revealed massive hepatic necrosis with diffuse hemorrhage. Developmental toxicity studies were done with MC-LR administered i.p. for 2-day periods: gestation days 7-8, 9-10 or 11-12. Doses used ranged from 2 to 128 microg kg(-1). On gestation day 17, fetuses were weighed and analyzed for gross morphological and skeletal defects. No treatment-related differences were seen in litter size, viability, weight or the incidence of anomalies. Groups of dams dosed with 32-128 microg kg(-1) on gestation days 7-8, 9-10 or 11-12 were allowed to give birth and the growth and development of their pups were followed postnatally. There were no significant effects noted in the offspring of the treated dams. Neurulation-staged CD-1 mouse conceptuses were exposed to 50-1000 nM MC-LR in whole embryo culture for 24 h. No significant increase in abnormalities or developmental delays was observed. Finally, exposure of the developing toad. Bufo arenarum was done from stage 17 (tail bud) for 10 days at concentrations of 1-20 mg l(-1). No effect on morphological development or survival was noted in any exposed groups. These data indicate that microcystin does not appear to affect development adversely in the mouse (in vivo or in vitro) or the toad at the doses and exposure parameters used.

Inhibition of cholinesterase enzymes following a single dermal dose of chlorpyrifos and methyl parathion, alone and in combination, in pregnant rats.

Pregnant Sprague-Dawley rats (14-18 d of gestation) were treated with either a single dermal subclinical dose of 30 mg/kg (15% of dermal LD50) chlorpyrifos (O,O-diethyl-O-[3,5,6-trichloro-2-pyridinyl] phosphorothioate) or a single dermal subclinical dose of 10 mg/kg (15% of dermal LD50) methyl parathion (O,O-dimethyl O-4-nitrophenyl phosphorothioate) or the two in combination. Chlorpyrifos inhibited maternal and fetal brain acetylcholinesterase (AChE) activity within 24 h of dosing, (48% and 67% of control activity, respectively). Following application of methyl parathion, peak inhibition of maternal and fetal brain AChE activity occurred at 48 h and 24 h after dosing (17% and 48% of control activity, respectively). A combination of chlorpyrifos and methyl parathion produced peak inhibition of maternal and fetal brain AChE activity at 24 h postdosing (35% and 73% of control activity, respectively). Maternal and fetal brain AChE activity recovered to various degrees of percentage of control 96 h after dosing. Application of methyl parathion or chlorpyrifos alone or in combination significantly inhibited maternal plasma butyrylcholinesterase (BuChE) activity. No significant inhibition of fetal plasma BuChE activity was detected. Peak inhibition of maternal liver BuChE occurred 24 h after application of methyl parathion or chlorpyrifos alone or in combination (64%, 80%, and 61% of control activity, respectively). Significant inhibition of placental AChE occurred within 24 h after application of methyl parathion or chlorpyrifos alone or in combination. The results suggest that methyl parathion and chlorpyrifos, alone or in combination, were rapidly distributed in maternal and fetal tissues, resulting in rapid inhibition of cholinesterase enzyme activities. The lower inhibitory effect of the combination could be due to competition between chlorpyrifos and methyl parathion for cytochrome P-450 enzymes, resulting in inhibition of the formation of the potent cholinesterase inhibitor oxon forms. The faster recovery of fetal plasma BuChE is attributed to the de novo synthesis of cholinesterase by fetal tissues compared to maternal tissues.

Species diagnosis and Bacillus thuringiensis resistance monitoring of Heliothis virescens and Helicoverpa zea (Lepidoptera: Noctuidae) field strains from the southern United States using feeding disruption bioassays.

Validation of a feeding disruption bioassay for the detection of resistance to Bacillus thuringiensis toxin and species identification is reported using field strains of Heliothis virescens and Helicoverpa zea collected from the southern United States in 1998. Feeding disruption is measured by a lack of fecal production from larvae exposed to a diagnostic concentration of CryIAc in a blue indicator diet. The bioassay provided rapid (24 h) diagnosis of the species composition of larvae tested and also monitored for the presence of resistance in H. virescens. An additional diagnostic concentration was established for monitoring resistance in H. zea. A probit model was used to compare the fecal production responses of insect strains over a range of CryIAc doses. Probability calculations, derived from our assay results, are also presented to aid in the interpretation of future results from field trials. Integration of the feeding disruption bioassay into integrated pest management programs is discussed.

Effect of whole and expanded-expelled cottonseed on milk yield and blood gossypol.

Thirty-two primiparous and 12 multiparous Holstein cows were randomly assigned at calving to treatments to determine the effects of type and amount of cottonseed product on plasma gossypol, milk production, and composition, and conjugated linoleic acid concentration in milk fat. Rations consisted of corn silage, corn grain, soybean meal, and cottonseed hulls, and contained on average 16.8% crude protein and 25.3% acid detergent fiber on a dry matter basis. On a dry matter basis, diets contained one of the following: 1) 14% whole cottonseed; 2) 14% expanded-expelled cottonseed; 3) 21% expanded-expelled cottonseed; or 4) 28% expanded-expelled cottonseed. Cows remained on treatment from 30 through 120 d in milk. Dry matter intakes were not significantly different, but intakes of crude protein, acid detergent fiber, and fat were higher for multiparous cows fed whole cottonseed. Multiparous cows fed whole cottonseed had higher yields of milk, fat-corrected milk, crude protein, fat and solids-not-fat than those fed any level of expanded-expelled cottonseed. Concentrations of milk fat, protein, and SNF were not affected by treatment. Although there were treatment differences in fat intake, there were no production differences in primiparous cows. Milk production efficiency (fat-corrected milk/dry matter intake) was not affected by treatment for either multiparous or primiparous cows. Cows fed 14% whole or 14% expanded-expelled cottonseed had similar levels of total plasma gossypol and plasma levels of the negative isomer of gossypol. Increasing the level of expanded-expelled cottonseed in the diet increased both total plasma gossypol and the negative isomer. In this experiment, multiparous but not primiparous cows fed whole cottonseed produced more milk than those fed expanded-expelled cottonseed at 14 to 28% of the diet dry matter, however, feed efficiencies were similar for all treatments.

Placental transfer and pharmacokinetics of a single oral dose of [14C]p-nitrophenol in rats.

The pharmacokinetics and placental transfer of a single oral dose of 100 mg/kg (10 microCi/kg, 16% of acute oral LD50) of uniformly phenyl-labeled [14C]p-nitrophenol were investigated in pregnant Sprague-Dawley rats at 14-18 days of gestation. Three animals were killed on gestation day 18, at 0.5, 1, 2, 4, 12, 24, and 48 h after dosing. Radioactivity was rapidly absorbed and distributed throughout the maternal and fetal tissues. The gastrointestinal tract contents retained 20% and 2% of the dose at 0.5 h and 4 h after dosing. The peak maternal plasma concentration of radioactivity (microg p-nitrophenol equivalent/ml) was 7.17 compared with 0.37 for fetal plasma at 0.5 h. Maximum concentration of radioactivity (microg p-nitrophenol equivalent/g fresh tissue) was detected in most tissues 0.5 h after dosing and was in descending order: kidney 23.27, liver 12.37, placenta 3.56, fetus 2.17, and brain 1.99. Radioactivity was eliminated from plasma and all tissues beiexponentially. The half-lives of elimination of 14C were 34.65 h and 69.30 h for maternal and fetal plasma, respectively. p-Nitrophenol, detected by HPLC, was the major compound identified in plasma and tissues. While p-nitrophenol disappeared biphasically from maternal plasma and kidney, it was eliminated monophasically from brain, placenta, and liver. p-Nitrocatechol and p-aminophenol were detected in the liver with peak concentrations at 0.5 h of 1.13 and 1.00 microg/g fresh tissue, respectively. While the change in the concentration of p-nitrocatechol with time was monophasic, that of p-aminophenol showed a biphasic pattern with elimination half-lives of 1.93 h and 4.95 h, respectively. Radioactivity was rapidly excreted in the urine mostly as polar metabolites, while only 3% of the dose was recovered in the feces. Radioactive materials excreted in the urine comprised: glucuronides 4%, sulfates 8%, hot-acid hydrolysates 11%, nonconjugated compounds 16%, and water-soluble metabolites 61%. This study demonstrated that although orally administered p-nitrophenol is a rapidly absorbed and excreted compound, it is transported to the maternal brain and the fetus and may pose a health risk following exposure to toxic doses during pregnancy.

5-AZA-2'-deoxycytidine-induced dysmorphogenesis in the rat.

5-aza-2'-deoxycytidine (d-AZA) causes temporally related defects in the developing mouse. Treatment of 1.0 mg/kg on gestation day (GD) 8 results in axial skeletal defects; on GD9, cleft palate and vertebral defects; on GD10, hindlimb phocomelia; and on GD11, digital defects. An unusual aspect of d-AZA teratogenicity in mice is that the phocomelia appears to be specific to the hindlimb, and the forelimb is not similarly affected regardless of treatment day. The current study was initiated to evaluate the embryonic response of another species, the rat, to this unique teratogen. Pregnant Sprague Dawley (CD) rats were treated with d-AZA or vehicle control. The compound was administered i.p. on GD9, 10, 11, or 12 to parallel developmental staging of the mouse. The highest dose (1.0 mg/kg) elicited effects indicating increased sensitivity to the compound in the rat as compared to the mouse. GD9 treatment was characterized by massive resorptions; GD10, by a predominance of axial skeletal defects and cleft palate; GD11, by a predominance of forelimb phocomelia and missing ribs; and GD12 by hindlimb phocomelia and forelimb digit defects. These data indicate significant differences in the developmental responses to d-AZA of the mouse and the rat. This may reflect interspecies differences in the temporal expression of genes involved in morphogenesis and/or the methylation patterns of such genes. Molecular data generated in the mouse will be compared to that of the rat to further characterize the developmental dynamics responsible for the interspecies differences. Teratogenesis Carcinog. Mutagen. 19:329-338, 1999.

Perceptions of veterinarians regarding privatization of veterinary services delivery in Ghana and Jamaica.

There are on-going reforms in the delivery of veterinary services in many developing countries, with privatization of certain veterinary activities as one of the approaches. In Jamaica, with the support of veterinarians, clinical aspects of veterinary services were privatized in 1992. In contrast, Ghanaian veterinarians are generally wary of the government's on-going privatization process. The objective of this study was to find out if perceptions of the veterinarians from these two countries on certain issues of privatization were sufficiently different to explain the willingness or reluctance to go into private practice. The response proportions for predominantly self-administered questionnaires were 83% (121/145) and 92% (35/38) for Ghana and Jamaica, respectively. There was a very good (92%) agreement in the perceptions of veterinarians in Ghana and Jamaica on a battery of 24 responses pertaining to privatization of veterinary services. Generally, the perceptions of the veterinarians in Ghana and Jamaica were similar even though the predominant delivery systems for animal health services were different. Therefore, reasons other than those examined in this study may explain the differences in willingness to go into private practice. The need to account for these other reasons is discussed.

Financing the delivery of animal health services in developing countries: a case study of Ghana.

Inadequate financing for the delivery of animal health services in many developing countries has been blamed for lack of efficiency and effectiveness of veterinary services. There are no reports of how the delivery of veterinary services in Ghana is financed. The aim of this paper is to provide information on the funding of veterinary services in Ghana to help in decision making on resource allocation. Various indicators and measures were used in assessing the adequacy of financing and resource allocation from 1990 to 1995. These measures were the veterinary budget as proportions of the national budget, GDP and AGDP; the proportions of the veterinary budget allocated to salaries; the ratios of salaries to non-staff expenditure and of non-staff expenditure to veterinary livestock units and technical staff; coefficient of efficacy; and R-ratio. These generally declined or worsened over the period, deviating from recommended norms where such norms exist. This confirmed the paucity of financing and resource allocation for the delivery of veterinary services. Revenue generation from cost recovery over the 1993-95 period was a potential source of funding, exceeding 100% of non-staff expenditure for 1993 and 1994. However, the revenue generated was not channelled back to veterinary services but went to the national coffers. This served as a disincentive. There is an urgent need to review how veterinary services are financed in Ghana, if the delivery of services is to improve in efficiency and effectiveness.

Perceived constraints to privatization of delivery of veterinary services in Ghana.

Ghana is on the verge of privatizing selected activities in the delivery of animal health services. However, various constraints are being encountered. The aim of this paper is to identify these constraints so as to help find and solutions to them. Questionnaires were administered to veterinarians in Ghana to elicit their responses on various issues concerning privatization. A significant proportion (61%) of government veterinarians, who formed 94% of the respondents, were unwilling to go into private practice. Among the reasons given were that private practice was too risky, that farmers were unwilling or unable to pay for services, that capital to start practices was lacking and that the societal value for animals was low. Also, low livestock densities in many areas and the absence of commercial livestock farming were perceived as deterrents to the sustainability of private practice. Furthermore, the poor macroeconomic environment of high inflation, high interest rates and unstable currency discouraged investment. If privatization of veterinary services is to succeed in Ghana, these perceptions have to be addressed and solutions found, since veterinarians are the targets of the privatization process.

Perceptions of veterinarians regarding privatization of veterinary services delivery in Ghana and Jamaica

There are on-going reforms in the delivery of veterinary services in many developing countries, with privatization of certain veterinary activities as one of the approaches. In Jamaica, with the support of veterinarians, clinical aspects of veterinary services were privatized in 1992. In contrast, Ghanian veterinarians are generally wary of the government's on-going privatization process. The objective of this study is to find out if perceptions of the veterinarians from these two countries on certain issues of privatization were sufficiently different to explain the willingness or reluctance to go into private practice. The response proportions for predominantly self-administered questionnaires were 83 percent (121/145) and 92 percent (35/38) for Ghana and Jamaica, respectively. There was a very good (92 percent) agreement in the perceptions of veterinarians in Ghana and Jamaica on a battery of 24 responses pertaining to privatization of veterinary services. Generally, the perceptions of the veterinarians in Ghana and Jamaica were similar even though the predominant delivery systems for animal health services were different. Therefore, reasons other than those examined in this study may explain the differences in willingness.(Au)

A preliminary survey of antibiotic residues and viable bacteria in milk from three Caribbean Basin countries.

There is widespread concern about the presence of antimicrobial drugs in milk. The presence of drug residues in milk may have public health implications. Milk samples (n = 25 to 65/country) were collected from bulk tanks and commercial vendors in Barbados, Costa Rica, and Jamaica between February 1996 and August 1997. Bulk tank samples were collected from high milk-producing regions of Jamaica and Costa Rica and from 26 dairy farms in Barbados. Milk pH, bacterial growth (total CFU/ml and the presence of Streptococcus agalactiae and Staphylococcus aureus), and the presence of antimicrobials were determined. Milk samples were tested by a microbial inhibition test (Delvotest-P, Gist-Brocades Food Ingredients, Inc.) to screen for antimicrobial drugs. All positives were retested for the presence of beta-lactam antibiotics after incubating with penicillinase and some positives were identified by high-pressure liquid chromatography-UV. Mean pH values ranged from 6.5 to 6.7. S. aureus was identified in bulk tank samples from Costa Rica (52%), Barbados (44%), and Jamaica (46%). S. agalactiae was identified in bulk tank samples from Costa Rica (28%), Barbados (8 and 16%), and Jamaica (18%). Antimicrobial residues were detected in some bulk tank samples from Barbados (8%) and Jamaica (10%) but not in samples from Costa Rica. All positives in milk from Jamaica and Barbados were determined to be beta-lactams. No residues were detected in pasteurized milk samples from Barbados or ultrahigh-temperature milk from Jamaica. The presence of beta-lactam residues in some of these samples suggests the appropriateness of testing milk prior to processing for consumption.