Serological diagnosis of neosporosis in a herd of dairy cattle in southern Brazil.

Neospora caninum-specific antibodies were detected in 60 of 172 (34.8%) dairy cattle by enzyme-linked immunosorbent assay (ELISA) in a herd from Parana State, Brazil. The seropositive animals included 47 of 126 (37.3%) adult cows, 7 of 29 (24%) heifers (1-2 yr), 4 of 15 (27%) heifers (5 mo-1 yr), and 2 precolostral samples. Data collected over a 9-yr follow-up period revealed that the proportion of pregnancies ending in abortion was 20% (31/154) among ELISA seropositive cows and 8% (15/193) among seronegative cows. The farm recorded 46 abortions, of which 31 (67.3%) were from seropositive cows. All sera positive by ELISA (n = 60) and sera from cows (n = 11) that were ELISA-negative but that had aborted were tested by the indirect fluorescent antibody test (IFAT) at dilutions from 1:25 to 1:200. All sera from ELISA-positive cows (n = 47) had an IFAT titer of 1:25:35 (74%) of these sera were also seropositive at a dilution of 1:200 (IFAT). Cows seropositive by ELISA had a 4-fold increased risk of having aborted at least once, compared to ELISA-seronegative cows. This association was statistically significant (P = 0.0016). The attributable fraction for this association indicated that approximately 76% of the risk for a cow having a history of abortion was attributable to seroconversion to N. caninum.     

Postpartum reproductive management of dairy cows in a large Florida dairy herd

Dairy cows (n = 199) were assigned randomly at Day 14 post partum to a control group or a programmed reproductive treatment group (PRT). Cows in the PRT group received 8 ug of GnRH on Days 14 and 50 post partum and 25 mg of PGF2alpha injected on Days 21, 34 and 57 post partum. Cows in the PRT group had a greater frequency of progesterone (P4) concentrations > 1 ng/ml (50% vs 30%; P < 0.01). Frequency of cows having P4 > 1 ng/ml at both Days 21 and 34 post partum was greater in the PRT group than in the control group (39% vs 20%; P < 0.01). Accumulation of days with a palpable cystic ovary was lower in the PRT than the control group (11.4% vs 6.5%; P < 0.05). The frequency of anestrous cows through Day 57 post partum was not different between the 2 groups. Cows that were anestrous had a lower body condition score throughout the postpartum period than the cyclic cows (2.7 vs <3.0; P < 0.01). Conception rate to first service, conception rate to all services, services per conception and days open were not different between the groups. Intensity of estrus detection was low for the study based on a low estrus detection rate (42%) and a low palpation pregnancy rate index (below 68%) throughout the study period. Accuracy of estrus detection was low based on the distribution of normal interestrus intervals for the study (19 to 23 d; 13.5%). It is concluded that programmed reproductive treatments during the postpartum period are functionally effective relative to altered ovarian activity; however, potential advantages to such a system are not evident without good estrus detection practices in a large commercial herd.     

Effect of using a stand-off pad on Campylobacter jejuni strain diversity in a herd of dairy cows

Aim:  To determine the effect of stand-off pad (SOP) use on the prevalence and strain diversity of Campylobacter jejuni in a small herd of dairy cows.
Methods and Results:  Faecal samples were collected from 21 cows on four sampling occasions (events), one in each season, over 1 year. The cows usually grazed on pasture but during winter they spent 18 h a day on a SOP. Campylobacter prevalence ranged from 48–52% on pasture but was 62% on the SOP. The diversity of 386 C. jejuni isolates was determined using Enterobacterial Repetitive Intergenic Consensus polymerase chain reaction (ERIC/PCR). There were 11 ERIC types identified for the herd over the course of the study. Of those 11, four to seven (per event) were present when the cows were grazing pasture but only two during SOP use.
Conclusions:  The use of the SOP was associated with an increase in prevalence and a reduction in diversity of C. jejuni.
Significance and Impact of the Study:  The reduction in ERIC types on the SOP indicated an increase in transfer of only some strains of C. jejuni among the cows. One of these strains persisted throughout the study. The zoonotic potential of this strain warrants further investigation.     

A comparison of methods for the detection of Escherichia coli O157:H7 from artificially-contaminated dairy products using PCR

Rapid nucleic acid-based methods to detect human pathogens in foods are dependent on the reliability of the DNA or RNA extraction method used. Skim milk, non-fat dry milk, Cheddar and Brie cheese, and reconstituted whey powder were seeded with serially diluted (10(0)-10(7) cfu 10 ml(-1)) Escherichia coli O157:H7 and subjected to DNA extraction (i) directly from the food product using a solvent-based procedure and (ii) using a guanidinium isothiocyanate (GITC) procedure after previous bacterial concentration. Both the efficiency of DNA extraction and the overall PCR detection limits were evaluated. In almost all instances, the total DNA yield using the solvent method was greater than that obtained for the concentration method. However, the purity of the DNA obtained after bacterial concentration was significantly better than that obtained after organic extraction alone. PCR detection limits after each DNA recovery method varied with the specific food, ranging from 10(1) to 10(4) cfu ml(-1) for all products except whey powder. DNA yields and subsequent PCR detection limits for reconstituted whey powder were extremely poor, and neither procedural changes nor the addition of PCR enhancement agents were able to improve recovery and/or detection. It is concluded that the efficiency of DNA extraction is an extremely important and frequently overlooked variable impacting the overall detection limits of PCR-based detection strategies.     

The isolation and prevalence of campylobacters from dairy cattle using a variety of methods

Faecal samples from 94 dairy cows and 42 calves in three different herds were examined by a variety of techniques for campylobacters. Cefoperazone amphotericin teicoplanin (CAT) agar, modified cefoperazone charcoal deoxycholate agar (mCCDA), Karmali agar, and membrane filtration onto blood agar, were used with and without enrichment in CAT broth. Seventy-nine percent of cattle in herd A carried campylobacters, compared with 40% and 37·5% of cattle in herds B and C, respectively. Most animals carried only one species of Campylobacter . Campylobacter hyointestinalis was isolated most frequently (32% animals positive) with Camp. fetus subsp. fetus and Camp. jejuni subsp. jejuni detected in 11% and 7% of animals, respectively. In addition, a novel biotype of Camp. sputorum was isolated from 60% of 47 cows tested in herd A. Direct plating detected only two of the total of 40 animals positive for campylobacter. Enrichment in CAT broth before membrane filtration onto blood agar or CAT agar were the most successful methods of plating. Campylobacter sputorum was isolated from CAT agar and blood agar but not from mCCDA or Karmali agar. Karmali agar incubated at 30 °C was especially effective for isolating Camp. fetus subsp. fetus .     

Incidence and treatments of postpartum reproductive problems in a dairy herd

Incidence of assisted births, retained fetal membranes (RFM), and metritis were recorded in one hundred dairy cows from parturition through 14 days post-calving. Manual removal of RFM was not attempted. All RFM were excised inside the vulva and observations of natural RFM expulsion were recorded. Fifteen of 100 cows (15%) had assisted births, 27 (27%) had RFM, 8 (8%) had primary metritis not associated with other postpartum reproductive problems, and 26 (26%) had secondary metritis. Uterine swabs for culture were collected during the study from cows with postpartum reproductive problems. E . coli was the most common organism isolated (69.4%). Sensitivities of all isolates to penicillin, tetracycline, and triple sulfa were 44.0%, 59.5%, and 36.9% respectively. One of two antibiotic treatments were administered to cows with these postpartum reproductive problems. Treated animals received either 5 g. tetracycline powder IU on day 1 of treatment plus 10.5 million units procaine penicillin G IM on days 1, 2, and 3; or 4 Sulfaurea boluses IU on day 1. Despite the antibiotic treatments, 26 of 34 cows having either assisted birth and/or RFM developed metritis (76%). Neither treatment regimen was superior to the other. The poor results of antimicrobial therapy suggested the futility of routine administration of therapeutic agents for postpartum reproductive problems. Treatment failure was attributed to ineffective drugs or inadequate dosage regimens.     

Mortality from asthma: a new epidemic in New Zealand

Trends in mortality attributed to asthma in the 5-34-year age group were examined in New Zealand, Australia, England and Wales, the United States, Canada, and West Germany for the years 1959-79. An epidemic of deaths from asthma occurred in the mid-1960s in New Zealand, Australia, and England and Wales but not in the other countries. In Australia and England and Wales the death rate quickly returned to pre-epidemic levels, but in New Zealand the decline in mortality was slow, and by 1974 the death rate was still almost double the pre-epidemic level. Of great concern was an abrupt increase in reported deaths from asthma in New Zealand after 1976 with the mortality rate during 1977-9 being greater than during the previous epidemic. In contrast, asthma mortality had remained relatively stable in the other populations.The new epidemic in New Zealand was investigated and appeared to be real. It could not be explained by changes in the classification of deaths from asthma, inaccuracies in death certification, or changes in diagnostic fashions. The most likely explanation appeared to be related to the management of asthma in New Zealand, and this is being investigated.     

Occurrence and significance of precipitating antibodies against thermophilic actinomycetes in the sera of dairy herd workers,Nangali, Delhi

The study was prompted by the lack of information on the role of thermophilic actinomycetes in hypersensitivity pneumonitis in India. It reports the occurrence of precipitating antibodies against clinically important thermophilic actinomycetes in the sera of a population sample of dairy herd workers, Nangali, Delhi. Of 112 workers investigated, 28 (25%) showed precipitins againstFaenia rectivirgula, 4 (3.2%) againstSaccharomonospora viridis, 2 againstThermoactinomyces thalpophilus and one each againstT. vulgaris andT. sacchari. The results of enzyme-linked immunosorbent assay (ELISA) indicated that IgG antibody activity againstF. rectivirgula was significantly higher in the symptomatic group than in the asymptomatic group (p<0.05) of workers and the controls (p<0.01). Significant difference inF. rectivirgula IgG activity was also obtained between the precipitin-positive symptomatic group and the precipitin-positive asymptomatic group (p< 0.05). In strong contrast, the IgG antibody activity againstT. thalpophilus was found to be uniformly low. A limited aeromicrobiological sampling of the dairy farm revealedS. viridis (55.8%) to be the commonest species followed byT. vulgaris (19.2%),T. thalpophilus (18.5%),F. rectivirgula (5%) andT. sacchari (15%). On the basis of suggestive clinical and laboratory findings, farmer's lung disease was suspected in four dairy herd workers. A comprehensive clinical evaluation including pulmonary function studies on the dairy herd workers and their long-term follow-up is indicated to determine the extent of respiratory morbidity caused byF. rectivirgula, S. viridis, T. thalpophilus, T. sacchari andT. vulgaris in India.     

A mixed methods inquiry: How dairy farmers perceive the value(s) of their involvement in an intensive dairy herd health management program

Background

Research has been scarce when it comes to the motivational and behavioral sides of farmers' expectations related to dairy herd health management programs. The objectives of this study were to explore farmers' expectations related to participation in a health management program by: 1) identifying important ambitions, goals and subjective well-being among farmers, 2) submitting those data to a quantitative analysis thereby characterizing perspective(s) of value added by health management programs among farmers; and 3) to characterize perceptions of farmers' goals among veterinarians.

Methods

The subject was initially explored by means of literature, interviews and discussions with farmers, herd health management consultants and researchers to provide an understanding (a concourse) of the research entity. The concourse was then broken down into 46 statements. Sixteen Danish dairy farmers and 18 veterinarians associated with one large nationwide veterinary practice were asked to rank the 46 statements that defined the concourse. Next, a principal component analysis was applied to identify correlated statements and thus families of perspectives between respondents. Q-methodology was utilized to represent each of the statements by one row and each respondent by one column in the matrix. A subset of the farmers participated in a series of semi-structured interviews to face validate the concourse and to discuss subjects like animal welfare, veterinarians' competences as experienced by the farmers and time constraints in the farmers' everyday life.

Results

Farmers' views could be described by four families of perspectives: Teamwork, Animal welfare, Knowledge dissemination, and Production. Veterinarians believed that farmers' primary focus was on production and profit, however, farmers' valued teamwork and animal welfare more.

Conclusion

The veterinarians in this study appear to focus too much on financial performance and increased production when compared to most of the participating farmers' expectations. On the other hand veterinarians did not focus enough on the major products, which farmers really wanted to buy, i.e. teamwork and animal welfare. Consequently, disciplines like sociology, economics and marketing may offer new methodological approaches to veterinarians as these disciplines have understood that accounting for individual differences is central to motivate change, i.e. 'know thy customer'.     

Bos indicus or Bos taurus mitochondrial DNA - comparison of productive and reproductive breeding values in a Guzerat dairy herd

The observation of bovine mitochondrial DNA (mtDNA) polymorphisms allows the separation of American zebu cattle, according to its maternal lineage ancestry, into two groups: one with Bos indicus mtDNA and other with Bos taurus mtDNA. The aim of the present study was to determine the productive and reproductive differences between these two groups, in a Guzerat dairy herd. The genotyping of a sample of 56 animals allowed the categorization of most of the 3835 animals in the pedigree file. The production file included 3528 calving and 3198 lactation records from 729 cows, born during the years 1947 to 2007. The traits considered were: lactation milk yield (LMY); days in milk (DIM); age at first calving (AFC), and calving interval (CI). Heritabilities and breeding values were estimated using an animal model. The regression of the average breeding values per year of birth indicated the genetic trends of the herd. The heritability coefficients estimated for LMY, DIM, AFC, and CI were 0.42, 0.43, 0.20, and 0.10, respectively. The genetic trends were similar for both groups, pointing to an improvement in the productive and a worsening in the reproductive traits. The two groups differed significantly regarding the average estimated breeding values for LMY, DIM and AFC, in the starting period, until 1970, but no differences were observed in the more recent years, after 1970. The segregation between the groups existed in the starting period, probably because the Bos taurus contributions to the herd had occurred more recently at that moment. The conclusion is that mtDNA has no significant effect on these traits.     

Factors affecting pregnancy loss from gestation Day 38 to 90 in lactating dairy cows from a single herd

The present study was designed to establish whether factors such as previous estrus synchronization, corpus luteum and embryo number at the time of pregnancy diagnosis, changes in body condition score, milk production, clinical disease (mastitis or lameness) and the inseminating bull affect pregnancy loss from 38 to 90 days of gestation. We derived data from 601 pregnant lactating dairy cows from a single herd. Pregnancy diagnosis was performed by ultrasonography between Day 38 and 44 following insemination. We also recorded corpus luteum and embryo number at this time. Pregnancy loss was defined as a negative pregnancy diagnosis on the second palpation per rectum undertaken between 90 and 96 days after insemination. Data were analyzed using multiple logistic regression methods. Cows that had an additional corpus luteum were eight times less likely to miscarry. The risk of pregnancy loss was 3.1 times higher in cows bearing twins. A one unit reduction in body condition score from previous partum to 30 days postpartum resulted in a 2.4-fold increase in pregnancy loss. We noted a higher incidence of pregnancy loss in cows inseminated using semen from one of the six bulls used. This particular bull led to a 3.4-fold increase in the rate of pregnancy loss. Logistic regression analysis showed no significant effects of previous estrus synchronization, milk production, clinical disease, body condition at previous partum or at pregnancy diagnosis, or body condition change between previous partum and pregnancy diagnosis. Our findings indicate a positive relationship between the presence of an additional corpus luteum and the maintenance of gestation. Risk factors for pregnancy loss were twin pregnancy, reduced body condition after previous parturition and the inseminating bull.     

Factors affecting survivability of transferred whole and demi-embryos in a commercial dairy herd

Sixty Holstein donor cows were superovulated and embryos were collected during a 6-d (27 cows) and a 4-d (33 cows) period approximately 60 d apart. Forty-three donor cows yielded embryos. Ninety-one embryos graded 1 or 2 were split and transferred to 181 recipient Holsteins. Demi-embryos were graded 2, 2-, 3 and 3- prior to transfer. Pregnancy and calving percentages were similar for all demi-embryo grades, averaging 59 and 53% from the two donor groups, respectively. Twin demi-embryo pregnancies averaged 36 and 19% for embryos split at the compacted morula and blastocyst stages, respectively. Twin demi-embryo calvings averaged 30 and 15% for these same groups. Progesterone levels of recipients (of either whole or demi-embryos) of second period donors were measured. Pregnancy rate increased generally with level of progesterone; however, calving percentage was slightly greater for recipients with intermediate levels of progesterone (2-6 ng/ml). Multiparous cow (20) recipients of demi-embryos had 45% pregnancy and 40% calving, while nulliparous heifer (161) recipients averaged 59 and 53% pregnancy and calving, respectively.     

A comparison of three methods to assess land use impacts on biodiversity in a case study of forestry plantations in New Zealand

Purpose

The aim of this study is apply available methods to assess impacts on biodiversity from the land use caused by plantation grown radiata pine in New Zealand in a life cycle assessment framework. This is done both to quantify the impact as well as compare the results obtained by different methods.

Methods

Data on location and productivity for wood supply regions in New Zealand was assessed using three methods identified as relevant for the purpose. All data were related to a functional unit of 1 m³ of timber production.

Results and discussion

The results show both a significant difference in impact on biodiversity from land use in the different wood supply regions and a significant difference in the results from the three applied methods. Although some of the results obtained from the three methods were correlated, this was not consistent through all the results. The methodological variation emanates from the treatment of the characteristics of the wood supply regions and underlying assumptions, e.g. reference vegetation. Compared to a case study in Norway, the impact on biodiversity from plantation forestry in New Zealand is found to be relatively low following the applied methods and assumptions taken.

Conclusions

The study shows a significant variation in how impacts on biodiversity are assessed following different approaches. Research to harmonize methods to quantify impact on biodiversity is recommended, as well as exploring effects of different weighting of crucial aspects of biodiversity, such as rarity, abundance and species richness.     

Short-window spectral analysis using AMVAR and multitaper methods: a comparison

We compare two popular methods for estimating the power spectrum from short data windows, namely the adaptive multivariate autoregressive (AMVAR) method and the multitaper method. By analyzing a simulated signal (embedded in a background Ornstein–Uhlenbeck noise process) we demonstrate that the AMVAR method performs better at detecting short bursts of oscillations compared to the multitaper method. However, both methods are immune to jitter in the temporal location of the signal. We also show that coherence can still be detected in noisy bivariate time series data by the AMVAR method even if the individual power spectra fail to show any peaks. Finally, using data from two monkeys performing a visuomotor pattern discrimination task, we demonstrate that the AMVAR method is better able to determine the termination of the beta oscillations when compared to the multitaper method.     

Monitoring Ceratomyxa shasta infection during a hatchery rearing cycle: comparison of molecular, serological and histological methods

The prevalence of Ceratomyxa shasta infection in production stocks of steelhead Oncorhynchus mykiss and cutthroat trout O. clarki was monitored using a parasite-specific polymerase chain reaction (PCR) assay. For all 4 stocks of fish followed through their 1 yr rearing cycle, C. shasta infection was detected despite their genetic resistance to the disease and the treatment of the incoming water with ozone. Infection was confirmed using serological methods and standard histological procedures, except when prevalence was low (<10%). This suggests that at the lowest infection levels PCR is more sensitive than other methodologies, and can be used as an early indicator of infection. Results of the PCR assay continued to correlate with histological and serological detection as the numbers of parasites and the lesion severity increased over the rearing cycle. For both steelhead and cutthroat trout, early infections were characterized by large numbers of parasites on the epithelial surface, but with little associated inflammation. At release as yearlings, the infection prevalence in all stocks was greater than 90 % and the inflammatory response in many fish was extensive, with tissue necrosis and mucosal damage. Although C. shasta infections no longer result in high mortality at this facility, results of this study indicate that the parasite remains a contributor to low condition indices in these fish, despite their genetic resistance and ozone disinfection of the water supply.     

Rapid identification of yeasts by serological methods: a combined serological and biological method.

A total of 387 yeasts from the contents of the digestive tracts of domestic animals and poultry were identified by slide agglutination tests using factor antisera and urease tests. The results of this serological test were very satisfactory with respect to accuracy and rapidity, particularly when performed in combination with concomitant physiological tests only for assimilation of inositol and potassium nitrate. It may be concluded that such a combination of serological and biological tests is very useful for identifying yeast strains from various sources.     

A comparison of sampling methods for bluegreen lucerne aphid (Acyrthosiphon kondoi) in Canterbury,New Zealand

Abstract

Sampling of bluegreen lucerne aphid showed that the most efficient method differs according to the time of year and the height of the lucerne. In late June 1976, when the lucerne was short (mean height 3.6 cm), an area removal sample of 700 cm² was more efficient to achieve a 10% degree of precision (half-width of a confidence limit) than area samples of 80 and 300 cm², suction sampling of the same areas, and stem sampling. In early spring (lucerne height 11.7 cm) the 80 cm² area removal sample was the most efficient. Just before the second hay cut (late January), the length of lucerne stems (62.5 cm) precluded use of any area removal technique; stem samples were most efficient. The cost in time was fuliy considered in sampling method comparisons. Possible differences with population density were not considered.     

Comparison of Campylobacter jejuni genotypes from dairy cattle and human sources from the Matamata-Piako District of New Zealand

Aims: To identify the prevalence and types of Campylobacter jejuni carried by dairy cattle and the extent of overlap of these types with those causing disease in humans. Methods and Results: Faecal samples from 410 dairy cattle were collected from 36 farms in the Matamata-Piako district in New Zealand. Campylobacter jejuni was isolated on all 36 farms, with a prevalence of 51% (95% CI 45–57) in dairy cattle and 65% (95% CI 58–72) in calves. Eighty-nine of these isolates were typed using Penner serotyping and pulsed field gel electrophoresis and were compared with 58 human C. jejuni isolates from people resident within this study area. Conclusions: Campylobacter jejuni were found in the faeces of over half of the dairy cows and calves examined. Twenty-one per cent of the bovine isolates and 43% of the human isolates formed indistinguishable clusters of at least one bovine and one human isolate. Significance and Impact of the Study: While a direct link between bovine isolates and human cases was not demonstrated, the finding of indistinguishable genotypes among C. jejuni isolates from bovine and human sources confirms that dairy cows and calves are a potential source of human campylobacteriosis. Barriers to separate bovine faecal material from the general public are therefore important public health measures.