Important Disease Of Cattle Research Articles

Loop-mediated isothermal amplification (LAMP) assays for detection of Theileria parva infections targeting the PIM and p150 genes

We have developed two loop-mediated isothermal amplification (LAMP) assays for the detection of Theileria parva, the causative agent of East Coast fever (ECF), an economically important cattle disease in eastern, central and southern Africa. These assays target the polymorphic immunodominant molecule (PIM) and p150 LAMP genes. The primer set for each gene target consists of six primers, and each set recognises eight distinct regions on the target gene to give highly specific detection of T. parva. The detection limit of each primer set is 1 fg, which is equivalent to one copy of the PIM and p150 T. parva genes. These PIM and p150 LAMP primer sets amplify DNA of T. parva isolates from cattle and buffalo from different countries including Kenya, South Africa, Tanzania, Rwanda, Uganda and Burundi, indicating their ability to detect T. parva from different countries. With the advantages of simplicity, rapidity and cost effectiveness, these LAMP assays are good candidates for molecular epidemiology studies and for monitoring control programs in ECF-endemic, resource poor countries.

Seroprevalence of foot and mouth disease in Bench Maji zone,Southwestern Ethiopia

A cross-sectional sero-epidemological study was conducted in two districts of the Bench Maji Zone, Southwestern Ethiopia between November 2007 and February 2008 with the objective of determining the seroprevalence of Foot and Mouth Disease (FMD) in cattle and identifying the potential risk factors associated with the disease. Sera samples were collected from a total of 273 cattle in 98 herds. The sera were submitted to the National Veterinary Institute (NVI), Debre zeit, Ethiopia for screening using the 3ABC-ELISA. The overall seroprevalence of FMD was 12.08% (n=273). Significantly higher seroprevalence (20%) was recorded in the Surma district compared to the Semen Bench district (5.88%). Peasant associations (equivalent to villages in a district) had prevalence rates of 25, 20, 15, 8.16, 5.66 and 3.92% for Kibish, Tulgit, Koka, Aman, Mizan and Temenja-yasz respectively. From the various risk factors analyzed peasant associations, cross boundary movement and herd size were seen to be statistically associated (p<0.05) with the seroprevalence of FMD. There was no significant variation in seroprevalence among sex, age and herd type. The result of the present study showed that FMD is an important cattle disease in the study area. Thus, an appropriate control strategy has to be designed and applied which could involve regulation of transboundary cattle movement and vaccination using the circulating virus strain. Key words: Bench Maji zone, cattle, FMD, risk factors, sero-epidemiology.

Participatory appraisal of foot and mouth disease in the Afar pastoral area, northeast Ethiopia: implications for understanding disease ecology and control strategy

Foot and mouth disease (FMD) is the most economically important disease of livestock that still affects extensive areas of the world. This study described the use of participatory appraisal tools such as pair-wise ranking, matrix scoring and proportional piling to assess the perception of livestock keepers about the clinical signs and epidemiological features of cattle diseases with particular emphasis on FMD. Strong agreement among informant groups (W = 0.710; P = 0.000) in pair wise ranking indicated that the diseases were common problem to all the selected districts. Matrix scoring of disease indicators/signs also showed strong agreement (W = 0.504 to 0.955; P = 0.000) that implied significant current veterinary knowledge by Afar pastoralists. Age specific means of annual incidence rates estimated by proportional piling were significantly (P < 0.05) different but negatively correlated for FMD, CBPP and pasteurellosis. However, correlation was not significant for anthrax, blackleg and other important diseases. Age specific means of annual mortality was significantly (P < 0.05) but negatively correlated for FMD, CBPP, pasteurellosis and other important cattle diseases with correlation coefficients of -0.72, -0.81, -0.8 and -0.55, respectively. However, correlation (r = 0.12) was not significant for anthrax and not correlated at all for blackleg. This study indicated that pastoralists have detailed knowledge about their livestock health problems, and hence the combined use of participatory appraisal and conventional methods is essential for an ultimate disease control strategy.

Quantification of &lt;I&gt;Theileria parva&lt;/I&gt; in &lt;I&gt;Rhipicephalus appendiculatus&lt;/I&gt; (Acari: Ixodidae) Confirms Differences in Infection Between Selected Tick Strains

Theileria parva is the etiologic agent of East Coast fever, an economically important disease of cattle in sub-Saharan Africa. This protozoan parasite is biologically transmitted by Rhipicephalus appendiculatus (Neumann) (Acari: Ixodidae). An understanding of the vector-parasite interaction may aid the development of improved methods for controlling transmission. We developed quantitative polymerase chain reaction (qPCR) and nested PCR (nPCR) assays targeting the T. parva-specific p104 gene to study T. parva pathogenesis in two strains of R. appendiculatus that had previously been selected to be relatively more (Kiambu) or less (Muguga) susceptible to infection. Nymphs from both strains were fed simultaneously to repletion on acutely infected calves. Nymphs from the Kiambu strain showed significantly higher engorgement weights compared with Muguga strain nymphs. Immediately after engorgement qPCR confirmed that nymphal Kiambu ticks had significantly higher parasite loads at repletion than Muguga nymphs. By 12 d postengorgement, parasites were below quantifiable levels but could be detected by nPCR in 83-87% (Muguga and Kiambu, respectively) of nymphs. After the molt, adult feeding on naïve cattle stimulated parasite replication in the salivary glands. PCR detected significantly more infected ticks than microscopy, and there was a significant difference between the two tick strains both in the proportion of ticks that develop salivary gland infections, and in the number of parasites within infected salivary glands. These data confirm that although both tick strains were competent vectors, Kiambu is both a significantly more susceptible and a more efficient host for T. parva than Muguga. The mechanisms that contribute to the levels of susceptibility and efficiency are unknown; however, this study lays the groundwork for a comparison of the transcriptome of these tick strains, the next step toward discovering the genes involved in the tick-parasite interaction.

Construction of a recombinant BHV-1 expressing the VP1 gene of foot and mouth disease virus and its immunogenicity in a rabbit model

Foot-and-mouth disease (FMD) and infectious bovine rhinotracheitis (IBR) are two important infectious diseases of cattle. Using bovine herpesvirus type 1 (BHV-1) as a gene delivery vector for development of live-viral vaccines has gained widespread interest. In this study, a recombinant BHV-1 was constructed by inserting the synthetic FMDV (O/China/99) VP1 gene in the the gE locus of BHV-1 genome under the control of immediately early gene promoter of human cytomegalovirus (phIE CMV) and bovine growth hormone polyadenylation (BGH polyA) signal. After homologous recombination and plaque purification, a recombinant virus named BHV-1/gE(-)/VP1 was acquired and identified. The immunogenicity was confirmed in a rabbit model by virus neutralization test and enzyme-linked immunosorbent assay (ELISA). The result indicated that the BHV-1/gE(-)/VP1 has the potential for being developed as a bivalent vaccine for FMD and IBR.

Characterisation and validation of farmers’ knowledge and practice of cattle trypanosomosis management in the cotton zone of West Africa

We carried out a knowledge, attitude, practice (KAP) survey on how farmers ( n = 895) manage cattle trypanosomosis in Burkina Faso, Mali and Guinea. Most farmers (96%) recognised the common signs of trypanosomosis, 70% knew the role of tsetse flies in transmitting the disease and 96% had knowledge of drugs used for treatment. Farmers reported that trypanosomosis was the most important cattle disease and estimated that 25% of their herd fall sick each year and 18% of the sick animals die. Nearly all sick animals (90%) were treated with trypanocides and most treatments were administered by untrained farmers. Giving drugs was the strategy most used as primary means of protection (50% of farmers) followed by avoiding high risk areas (32% of farmers) and keeping trypanotolerant cattle (7% of farmers). Few farmers knew about communal tsetse control methods and those who did, rarely practiced them. Farmer diagnosis of trypanosomosis in cattle presented at clinics ( n = 113) was in most cases (84%) supported by laboratory tests. However, the signs that most farmers considered indicative of trypanosomosis (staring coat and emaciation) were poor predictors of trypanosomosis. We tested farmer knowledge of injection sites and trypanocide dilutions ( n = 423 cattle), and while few (15%) farmers gave under-dosages or over-dosage (2% of farmers), injection techniques were poor with injection-related side effects in 24% of cattle treated by farmers. Despite this, therapeutic outcomes were both objectively (clinical parameters) and subjectively (carer assessment) satisfactory in 89% of cattle treated by farmers. This study found that farmers play a major role in successfully managing trypanosomosis and recommends the recognition and support for community based treatment.

Analytical specificity and sensitivity of a real-time polymerase chain reaction assay for identification of bovine mastitis pathogens

Intramammary infection (IMI), also known as mastitis, is the most frequently occurring and economically the most important infectious disease in dairy cattle. This study provides a validation of the analytical specificity and sensitivity of a real-time PCR-based assay that identifies 11 major pathogen species or species groups responsible for IMI, and a gene coding for staphylococcal β-lactamase production (penicillin resistance). Altogether, 643 culture isolates originating from clinical bovine mastitis, human, and companion animal samples were analyzed using the assay. The isolates represented 83 different species, groups, or families, and originated from 6 countries in Europe and North America. The analytical specificity and sensitivity of the assay was 100% in bacterial and β-lactamase identification across all isolates originating from bovine mastitis (n=454). When considering the entire culture collection (including also the isolates originating from human and companion animal samples), 4 Streptococcus pyogenes, 1 Streptococcus salivarius, and 1 Streptococcus sanguis strain of human origin were identified as Streptococcus uberis, and 3 Shigella spp. strains were identified as Escherichia coli, decreasing specificity to 99% in Strep. uberis and to 99.5% in E. coli. These false-positive results were confirmed by sequencing of the 16S rRNA gene. Specificity and sensitivity remained at 100% for all other bacterial targets across the entire culture collection. In conclusion, the real-time PCR assay shows excellent analytical accuracy and holds much promise for use in routine bovine IMI testing programs. This study provides the basis for evaluating the assay's diagnostic performance against the conventional bacterial culture method in clinical field trials using mastitis milk samples.

Single-Chain Antibody Fragments from a Display Library Derived from Chickens Immunized with a Mixture of Parasite and Viral Antigens

Phage-displayed chicken single-chain antibody fragment libraries can provide useful diagnostic and research reagents. Using avian immunoglobulin genes simplifies the construction of such repertoires since far fewer primer sets are required to access the avian antibody repertoire than is the case with mice or humans. Libraries constructed using mRNA from an immune source are enriched in affinity-matured sequences and consequently need not be as large as "universal" non-immune repertoires to have a reasonable probability of yielding high-affinity binders. Repertoires focused on a number of defined targets can be constructed using lymphocyte mRNA from chickens immunized with a mixture of several different antigens. This approach was evaluated with the aim of economically and rapidly deriving immunodiagnostic reagents for malaria, trypanosomiasis, and malignant catarrhal fever, all of which are important to health or food security in Africa. Two chickens were each immunized with a mixture comprised of recombinantly expressed histidine-rich protein, the aldolase and the lactate dehydrogenase of Plasmodium falciparum, the variant surface glycoprotein of Trypanosoma sp., and purified malignant catarrhal fever virus, a herpesvirus that causes an economically important disease of cattle and other ruminants. Immune responses to each of the individual antigens were determined by extracting egg-yolk IgY and testing for antigen-specific antibodies in ELISA. The chicken splenocytes were then recovered, RNA was extracted, and after reverse transcription, the immunoglobulin VH and VL regions were amplified by PCR and joined via a single glycyl residue for surface expression on a collection of filamentous bacteriophages. The resulting display library was then screened by panning to isolate binders. The immunized chickens did not, however, respond equally well to all the different antigens, nor was it possible to derive antibody fragments against all the targets. These limitations notwithstanding, several useful binders with the potential to be used in malaria diagnosis were obtained.

Comparative efficacy of tulathromycin versus combination of florfenicole & oxytetracycline in the treatment of undifferentiated respiratory diseases in feedlot calve

Respiratory disease is one of the most important diseases in sheep and cattle and economic losses due to disease are so important for food animal producing country. Tulathromycin (TUL) is a semi-synthetic, long acting Antibiotic which belongs to the macrolide group. It uses as an antibiotic in the treatment of respiratory diseases in domestic animals. In this study 200 calves that exhibiting clinical signs of respiratory disease with undifferentiated etiology selected & divided in to two groups. Group 1 treated with single injection of TUL 2.5 mg/kg BW SC and Group 2 treated with combination of oxytetracycline(OTC) 20 mg/kg BW IM & florfenicole (FFC) 40 mg/kg BW SC. Treated animals were examined 5 days after injection. In the first group (TUL) 89 calves showed sings of cure 5 days later after first injection. 11 calve needed further treatment in which 5 calve cured and 6 calve died. In the second group (OTC & FFC) 84 calves showed sings of cure 5 days later after single injection. 16 calves needed further treatment, of which 7 calves cured and 9 calves died. The results of this study indicates that usage of TUL is more effective than combination of FFC & OTC in treatment of respiratory disease with undifferentiated etiology and efficacy increased & mortality rate decreased considerably.

Fusobacterium necrophorum: A ruminal bacterium that invades liver to cause abscesses in cattle

Fusobacterium necrophorum, a Gram-negative, rod-shaped, and an aerotolerant anaerobe, is a normal inhabitant of the rumen of cattle. The organism is in ruminal contents and adherent to the ruminal wall. Its role in ruminal fermentation is to metabolize lactic acid and degrade feed and epithelial proteins. The ruminal concentration is higher in grain-fed than forage-fed cattle. From the rumen, the organism gains entry into the portal circulation and is trapped in the liver to cause abscesses. The organism is an opportunistic pathogen and a primary causative agent of liver abscesses, an economically important disease of grain-fed cattle. Liver abscesses are often secondary to ruminal acidosis and rumenitis in grain-fed cattle. Two subspecies of F. necrophorum, subsp. necrophorum (biotype A) and subsp. funduliforme (biotype B), are recognized that can be differentiated based on morphological, biochemical, biological and molecular characteristics. The subsp. necrophorum is more virulent and is isolated more frequently from infections than the subsp. funduliforme. Several toxins or secreted products have been implicated as virulence factors. The major factors contributing to ruminal colonization and invasion into the liver are hemagglutinin, endotoxin and leukotoxin, of which leukotoxin is the protective antigen. In some conditions, the organism synergistically interacts with Arcanobacterium pyogenes, a facultative anaerobic organism and a secondary etiologic agent, to cause liver abscesses.

β 2 integrin Mac-1 is a receptor for Mannheimia haemolytica leukotoxin on bovine and ovine leukocytes

Pneumonia caused by Mannheimia haemolytica is an important disease of cattle (BO), domestic sheep (DS, Ovis aries) and bighorn sheep (BHS, Ovis canadensis). Leukotoxin (Lkt) produced by M. haemolytica is cytolytic to all leukocyte subsets of these three species. Although it is certain that CD18, the β subunit of β 2 integrins, mediates Lkt-induced cytolysis of leukocytes, whether CD18 of all three β 2 integrins, LFA-1 (CD11a/CD18), Mac-1 (CD11b/CD18) and CR4 (CD11c/CD18), mediates Lkt-induced cytolysis of BO, DS and BHS leukocytes remains a controversy. Based on antibody inhibition experiments, earlier studies suggested that LFA-1, but not Mac-1 and CR-4, serves as a receptor for M. haemolytica Lkt. PMNs express all three β 2 integrins, and they are the leukocyte subset that is most susceptible to Lkt. Therefore we hypothesized that all three β 2 integrins serve as the receptor for Lkt. The objective of this study was to determine whether Mac-1 of BO, DS and BHS serves as a receptor for Lkt. cDNAs for CD11b of BO, DS and BHS were transfected into a Lkt-non-susceptible cell line along with cDNAs for CD18 of BO, DS and BHS, respectively. Transfectants stably expressing BO, DS or BHS Mac-1 specifically bound Lkt. These transfectants were lysed by Lkt in a concentration-dependent manner. Increase in intracellular [Ca 2+] i was observed in transfectants following exposure to low concentrations of Lkt indicating signal transduction through secondary messengers. Collectively, these results indicate that Mac-1 from these three species serves as a receptor for M. haemolytica Lkt.

Prevalence and Characterization of Bovine Viral Diarrhea Virus in the White-Tailed Deer Population in Indiana

Bovine viral diarrhea (BVD) is one of the economically important diseases of cattle. For many years, different types of vaccines have been commercially available, yet this disease is hard to control in high-density population areas. Detection and isolation of bovine viral diarrhea virus (BVDV) from any potential reservoir is vital, especially when considering virus eradication from a herd or locale. One potential source is wild ruminants. Ear notches and lymph nodes were collected from the wild population of white-tailed deer (Odocoileus virginianus) during deer hunting season in Indiana and tested for BVDV with a commercial BVD antigen capture enzyme-linked immunosorbent assay. Two samples out of 745 collected samples were positive, and subsequently cp and ncp BVDV was isolated from 1 ear notch and 1 lymph node. These isolates were genotyped as type 1a and 1b based on sequence analysis of the 5' untranslated region (UTR). The results of the present study indicate that the prevalence of BVDV in the white-tailed deer population of Indiana is about 0.3%. Wild ruminants infected with BVDV should be taken into consideration during an eradication program of BVDV from the livestock population.

Titrating Theileria parva: Single stocks against combination of stocks

Theileria parva is the causative agent of East Coast fever (ECF), an important cattle disease in East and Central Africa. One of the methods for control of ECF is ‘infection and treatment’, a procedure in which an animal is infected with the live parasite and at the same time treated with a long-acting oxytetracycline formulation, restraining the infection and allowing a protective cellular immune response to develop. Optimal immunizing doses were estimated using models of trichotomous response: dysimmunization (death or severe reaction during immunization), immunization failure (death or severe reaction during lethal challenge) and successful immunization (neither dysimmunization nor immunization failure). In this paper we present methods of interpreting immunization trials and apply these methods to previously unpublished data from two such trials: one with a mixture of three T. parva stocks and one with a single T. parva stock. We explain why titration trials conducted with a cocktail of antigens could predict a suboptimal immunization dose. Indeed it is possible for a combination of three individually efficient stocks to result in a mixture with which optimal immunization response might be difficult to achieve, because of averaging effects. The corresponding interpretation provides insights into why standard immunization trials for T. parva have not yielded the results that might be expected of them. The results of this work may also have implications for the use of antigen cocktails in cancer, HIV and malaria vaccine trials.

Economical Value of Mycobacterium avium subsp paratuberculosis Fecal Shedding and Culling Due to Clinical Johne's Disease on Minnesota Dairy Farms

Johne's disease (JD) is increasingly recognized as an important disease in dairy cattle in USA and throughout the world. The National Animal Health Monitoring System (NAHMS, 1996) has estimated that the annual cost to infected U.S. dairy operations is over $100 per cow in inventory, with higher costs of more than $200 per cow in inventory per year in herds with high infection levels. It is not only that these estimations were performed more than 10 years ago, they were based on serum ELISA test results, which is known to have less sensitivity than bacterial fecal culture and therefore can bias any prevalence estimation. The scientific literature provides limited information about the economical impact of Mycobacterium paratuberculosis (Map) fecal shedding in dairy cattle on lactation performance. Quantification of the monetary impact of Map fecal shedding or clinical JD on lactation performance is critical to participation by dairy cattle producers in JD control programs, because it enhances the relationship between stage of disease and economic loss. This information will allow dairy producers to make appropriate management decisions within their operations regarding implementation of control measures to decrease herd JD prevalence. The objective of this study was to evaluate the economical cost of Mycobacterium paratuberculosis (Map) fecal shedding prior to calving and of cows that were culled due to clinical Johne's disease (CCJD) during the subsequent lactation.

Clinical, humoral and IFN g responses of cattle to infection with &lt;i&gt;Mycoplasma mycoides&lt;/i&gt; var. &lt;i&gt;mycoides&lt;/i&gt; small colony and attempts to condition the pathogenesis of the infection

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides var. mycoides small colony (MmmSC), is one of the most important diseases of cattle in Africa. The role of innate or acquired cell mediated and humoral immunity in conferring protection against MmmSC infection has not yet been elucidated. On the other hand, the pathological lesions caused by the aetiological agent have been considered indicative of an immunopathological process. In this study ten naïve cattle were exposed to in-contact infection with animals infected by intubation with a strain of MmmSC. Clinical signs, antibody response, IFNgamma release and pathological changes at necropsy were analysed and compared with the events following in-contact infection of an equal number of animals kept under daily treatment with cyclosporine for the entire observation period of 84 days. Cyclosporine is a suppressor of the immune response related to the T-cell system. Under the conditions of the experiment, cyclosporine appeared to condition the pathogenesis of CBPP by delaying the events that follow infection, bringing further support to the possibility that the immune response may have an impact on the disease outcome.

Comparing FAMACHA © eye color chart and Hemoglobin Color Scale tests for detecting anemia and improving treatment of bovine trypanosomosis in West Africa

African animal trypanosomosis (AAT) is considered the most important cattle disease in sub-Saharan Africa but its diagnosis in the field is difficult, resulting in inappropriate treatments, excessive delay in treatments and under-treatment. A field study in West Africa investigated the usefulness of anemia in the diagnosis of trypanosomosis. A total of 20,772 cattle blood samples were taken from 121 villages in 3 countries. The average packed cell volume (PCV) of trypanosomosis positive cattle was 23%, versus 28% for negative cattle. In a sub-set of animals, other causes of anemia were investigated showing most of the anemia burden was attributable to trypanosomosis. Anemia was a reasonably accurate indicator of trypanosomosis in the study area, with a sensitivity of 56% and a specificity of 80% and a diagnostic odds ratio of 4.2, the highest of all the signs evaluated (anemia, emaciation, staring coat, lymphadenopathy, fever, lacrimation and salivary or nasal discharge). Having confirmed the usefulness of anemia as a predictor of trypanosomosis, two potential pen-side tests for anemia were evaluated (the first reported trial of their use in cattle), firstly a color chart developed for anemia detection in sheep through visual inspection of conjunctival membranes (FAMACHA ©) and secondly the Hemoglobin Color Scale (HbCS) developed for assessing hemoglobin levels in human patients by comparing blood drops on filter paper with color standards. In a population of cattle suspected by their owners to be sick with trypanosomosis ( n = 898) the sensitivity of the HbCS test was 56% and the specificity was 77%, while the sensitivity of the FAMACHA © test was 95% and the specificity was 22%. The higher sensitivity but lower specificity suggests the FAMACHA © may be useful as a screening test and the HbCS as a confirmatory test. The two tests were also evaluated in cattle randomly selected from the village herd. Using cut-off points to optimize test performance, the HbCS test had a sensitivity of 81% and a specificity of 62% ( n = 505 cattle), while the FAMACHA © had a sensitivity of 92% and a specificity of 30% ( n = 298 cattle). Recommendations are made for the appropriate use of these tests in the West African region.

An Essential Cell Cycle-regulated Nucleolar Protein Relocates to the Mitotic Spindle Where It Is Involved in Mitotic Progression in Trypanosoma brucei

TbNOP86 and TbNOP66 are two novel nucleolar proteins isolated in Trypanosoma brucei. They share 92.6% identity, except for an additional C-terminal domain of TbNOP86 of 182 amino acids in length. Both proteins are found in Trypanosomatidae, but similarity to other eukaryotic proteins could not be found. TbNOP86 and TbNOP66 are expressed at similar level in procyclic and bloodstream forms, although the relative level of expression of TbNOP66 is 11 times lower. TbNOP86 undergoes post-translational modifications, as it is found predominantly at 110 kDa compared with the predicted 86 kDa. Immunofluorescence of overexpressed ty-tagged TbNOP86 and TbNOP66 showed that both proteins accumulated in the nucleolus of G(1) cells. This was confirmed by the co-localization of an endogenous TbNOP86-myc with the nucleolar protein Nopp140. TbNOP86-ty localization is cell cycle-regulated, because it colocalizes with the mitotic spindle in mitotic cells. TbNOP86 is required for mitotic progression in both life stages as depleted cells are enriched in the G(2)/M phase. In procyclic cells, a reduced growth rate is accompanied by an accumulation of zoids (0N1K), 2N1K, and multinucleated cells (xNyK). The 2N1K cells are blocked in late mitosis as nucleolar segregation is completed. TbNOP86 depletion in bloodstream form caused a drastic growth inhibition producing cells bearing two kinetoplasts and an enlarged nucleus (1N(*)2K), followed by an accumulation of 2N2K cells with connected nuclei and xNyK cells. These studies of TbNOP86 provide a more comprehensive account of proteins involved in mitotic events in trypanosomes and should lead to the identification of partners with similar function.

Bovine Subclinical Ketosis in Dairy Herds in Iran

Subclinical ketosis (SCK) is defined as elevated concentrations of ketone bodies in the absence of clinical signs of ketosis. It is an important metabolic disease in dairy cattle during early lactation and is associated with losses in milk production and several other periparturient diseases. Limited information is available regarding the prevalence of SCK in dairy herds in Iran. The objectives of this study were (i) to determine the incidence of SCK in the dairy herds in Kerman province of Iran using serum beta-hydroxybutyrate (BHB) concentrations, and (ii) to investigate the relationship between serum concentrations of BHB and glucose of cows with SCK. In the present study, 90 multiparous Holstein cows (4-6 years old) from 11 commercial dairy herds were evaluated 3-4 weeks after calving. The distribution of blood BHB concentrations seemed to suggest a cut-off point of 1200 micromol/L between cows with and without SCK. At this cut-off point, 14.4% of tested cows (13/90) were classified as subclinically ketotic, with the prevalence rate within herd ranging from 10% to 20%. Cows with SCK were detected in all the investigated dairies except one. Blood glucose concentrations in cows with SCK were significantly lower (p < or = 0.05) than in cows without SCK, and serum BHB and glucose concentration were inversely correlated (r = -0.43, p < or = 0.05). The results suggest that, using a cut-off of 1200 micromol/L, BHB concentrations can be used during early lactation for diagnosis and to make management decisions for prevention and treatment.

Putative quantitative trait loci associated with the probability of contracting infectious bovine keratoconjunctivitis1,2

Infectious bovine keratoconjunctivitis, also known as pinkeye, is an economically important disease in cattle. The objective of this study was to detect QTL associated with infectious bovine keratoconjunctivitis in offspring from a Brahman x Hereford sire. The sire was mated to Hereford, Angus, and F1 cows to produce 288 offspring in 1994 and mated to MARC III ((1/4) Hereford, (1/4) Angus, (1/4) Red Poll, and (1/4) Pinzgauer) cows in 1996 to produce 259 offspring (547 animals total). Infectious bovine keratoconjunctivitis was diagnosed by physical examination in 36 animals of the family. Records included unilateral and bilateral frequency, but not severity. Records were binary: 0 for unaffected and 1 for affected cattle. A putative QTL for infectious bovine keratoconjunctivitis was identified on chromosome 1, with a maximum F-statistic (F = 10.15; P = 0.0015) at centimorgan 79 of the linkage group. The support interval spanned centimorgans 66 to 110. There was also evidence suggesting the presence of a QTL for infectious bovine keratoconjunctivitis on chromosome 20, with a maximum F-statistic (F = 10.35; P = 0.0014) at centimorgan 16 of the linkage group. The support interval ranged from centimorgan 2 to 35. This report provides the initial evidence of QTL for infectious bovine keratoconjunctivitis. Although a candidate gene was identified for one of the regions of interest, further studies are needed to identify the genetic basis of resistance to the disease.

Maasai perception of the impact and incidence of malignant catarrhal fever (MCF) in southern Kenya

We investigated the perceived impact of malignant catarrhal fever (MCF) to pastoralists in Isinya Division, a wildlife dispersal area of Nairobi National Park, and used a range of participatory epidemiology methodologies. We compared the relative importance, incidence and impact of MCF compared to other locally defined important diseases with a total of 158 respondents in 11 group meetings and 21 household meetings in July 2004. Direct losses due to disease were investigated through lowered prices as a result of the emergency sale of disease-infected animals. Overall, Maasai in Isinya Division perceived east coast fever (ECF) to be the most important cattle disease and to have the highest incidence. Anthrax was considered to have the largest impact. In areas within or adjacent to the wildebeest calving zone, MCF was perceived to be the most important cattle disease and also to have the largest impact. Outside the calving zone, MCF was considered the fourth-most important disease with the fourth largest impact, and these were areas where wildebeest were less common. MCF was also the fourth-most common disease, and across the Division incidence was estimated at 5% in calves and 10% in adults. However, MCF incidence varied greatly throughout the study area, from 3% to 12%, and the highest incidence risks were found in areas where wildebeest came to calve. The percent drop in sale price per animal infected with MCF was estimated at 50% for MCF for the year 2003–2004. Forced avoidance movements away from wildebeest calves were reported to decrease livestock production due to loss of access to prime grazing sites. As suggested by pastoralists in this study, the development of compensation schemes or incentives from wildlife would reduce the conflict between livestock keeping and wildlife conservation.