THE ECONOMICS OF CONTROLLING INFECTIOUS DISEASES ON DAIRY FARMS

Cost effective disease control on the dairy farm can enhance productivity and subsequently profitability. Previous economic studies on animal disease have focused on production losses and evaluation of disease eradication programs and provided little guidance as to the optimal prevention action. This paper presents a theoretical model on the economics of livestock disease and develops an empirical model to determine the optimal set of control strategies for four production limiting cattle diseases: bovine viral diarrhea (BVD), enzootic bovine leukosis (EBL), Johne's Disease (JD) and neosporosis. Control functions indicating the prevalence of infection with each of the four diseases for each of the ten strategies are estimated. The optimal strategies that minimize total disease cost (direct production losses and control expenditures) are provided for each disease on the basis of farm survey results from the Maritime provinces. The results emphasize the importance of introduction checks before new animals enter the herd and adequate vaccination protection as cost-effective control strategies.Farm Management, Livestock Production/Industries,

Impact of calf feeding practices on calf growth and health in smallholder dairy farms in Nyeri County, Kenya

The objective of this study was to assess potential impact of selected enhanced feeding practices on growth of smallholder dairy calves. In the period between May and August 2012, 36 privately owned Kenyan smallholder dairy farms with new-born calves were purposively selected to participate in a randomized control trial. The calves were randomly allocated to one of nine feed intervention groups based on three groups of Calf Starter Intake (CSI; 20% protein) and three groups of Milk Intake (MI): control, half, and full. Full CSI intake involved lead feeding to achieve up to 1 kg/day feed intake at weaning, half CSI was to maximize intake at 0.5kg/day at weaning, while control CSI was the farmers’ normal practice (0-0.2 kg/day). Full MI was 4 Liters/day and half milk intake was 2 Liters/day, while control MI was the farmers’ normal practice (2-10 Liters/day). Each of the nine intervention groups had four calves per group (one calf died during the 1st week) resulting in 35 calves. Data on calf weight and height were collected weekly through farm visits for a period of eight weeks, and management data were collected through an in-person questionnaire. The results showed significant differences in the mean average daily weight gains across the different feed intervention groups at P (<0.001). All full CSI groups had weight gains over 0.5 kg/day. The full CSI + control MI had a positive association with the mean average daily weight gain at (0.61 kg/day), higher than the other two full CSI groups because of higher MI in this small group. In mixed multivariable linear regression analyses, weekly calf weights were higher with calf age and body condition score, a normal gastrointestinal tract, and amount of calf starter consumed per day, along with feeding sweet potato vines. &nbsp

Seroprevalence and risk factors of Neospora caninum and Bovine Viral Diarrhoea Virus in smallholder dairy cattle in Kenya

Little is known of the risk factors associated with occurrence of Neospora caninum and Bovine Viral Diarrhoea Virus (BVDV) infection in Kenya. This cross-sectional study hypothesized that there are significant biosecurity measures associated with N. caninum and BVDV infections on smallholder dairy farms in Kenya that could be adopted to reduce seroprevalence and impacts. From 158 randomly selected farms in Meru County, Kenya, 470 serum samples were collected from dairy cattle (over six months of age and unvaccinated for these two pathogens). Sera were analyzed for antibodies to N. caninum and antibodies and antigens to BVDV. Data on risk factors were obtained through face-to-face interviews with the farmers. Multivariable logistic regression models were used to identify significant risk factors associated with seropositivity for the pathogens. The apparent seroprevalence of N. caninum, BVDV antibody, BVDV antigen, and co-infection with N. caninum and BVDV antibody and/or antigen were 35.1%, 47.1%, 36.2% and 18.5%, respectively. Risk factors associated with N. caninum antibody included: introducing milking cows into the farm, lending of cattle between farms, farm dogs having access to bovine aborted fetuses, and dogs whelping in the farm compound, with an interaction between the last two variables. BVDV antigen was associated with cattle having contact with pigs, and an interaction between cattle age and whether farms introduced new calves onto farms, and cattle age and whether visiting dairy farmers have access to the cow shed. Cows had higher odds of having BVDV antibodies compared to heifers. Factors associated with co-infection included cow parity, direct contact between dairy cattle, dogs and goats, and introducing new milking cows into the farms. Antibody and antigen results may be partly a function of classical swine fever virus or border disease virus interactions. Farmer education on these biosecurity measures is recommended, along with introduction of BVDV vaccination

A comparison between indirect ELISA and tuberculin skin test in the diagnosis of bovine tuberculosis in Kenya

Bovine tuberculosis (BTB) is an important zoonotic disease which has remained persistent in many areas of the World. Control and eradication has proved problematic due to the challenges in effective screening and diagnosis. Limited information on the status of BTB in Kenya presents a need to investigate its occurrence in cattle population. The study was carried out using an indirect antibody Enzyme Linked Immunosorbent Assay (ELISA-IDEXX-USA) to assess the agreement with Comparative Intradermal Tuberculin Test (CITT) test results between August and December 2013 in Laikipia County. The study also determined the apparent prevalence of cattle BTB antibodies in Laikipia County. A total of 276 bovine serum samples were tested using MPB70 and MPB83 recombinant proteins as capture antigens in the ELISA kit. Data were recorded in Microsoft Excel and exported to SPSS 16.0 for analysis. Apparent prevalence was calculated as a proportion at 95% CI, Kappa statistics computed, and test of significance assessed by Chi-square and Fisher exact test.  The results showed an individual animal apparent prevalence of 3.9% (11/276) and a herd prevalence of 58.3% (7/12). There was no significant association between BTB infection and both animal level factors, breed and sex. Kappa agreement test between ELISA test and TST showed a good agreement at K= 0.65. This study reported the prevalence of BTB in cattle for the first time in Laikipia County Kenya using the IDEXX ELISA. The ELISA test was comparable to the tuberculin test which is used as the gold standard for screening TB on live animals. The two tests can be used alongside for series or parallel interpretation to achieve desirable diagnostic sensitivity and specificity in disease control programs

Cross-sectional study of cow comfort and management factors associated with subclinical mastitis in smallholder dairy farms in Kenya

A number of environmental and contagious factors have been associated with subclinical mastitis (SCM), which is a common and costly problem for smallholder dairy farmers (SDF). We conducted a cross-sectional study on 118 cows in their first two months post-calving on 109 SDF in Kenya. The study objective was to investigate the relationships among various cow and farm management parameters and SCM specific to SDF. The stall floor comfort level was assessed through knee impact and wetness tests, and cleanliness on the leg and udder were also scored. Various mastitis prevention measures were also assessed (e.g., milking protocols, and use of teat dip and dry cow therapy). Individual quarter SCM was assessed on each cow using California Mastitis Test (CMT). Univariable and multivariable logistic regression models were fit to determine management factors associated with cow-level SCM. Farm-level, cow-level and quarter-level prevalence of SCM was 45.9% (50/109), 43.2% (51/118) and 21.9 % (103/471), respectively. The proportion of stalls scored as dirty was 33.1% while 49.1% of cows had dirty legs. Only 10.1% of farms were using either disinfectant teat dip or dry cow therapy (or both) to prevent mastitis. Low parity and poor stall hygiene were significantly associated with occurrence of SCM. At high daily milk yield, the probability of having SCM was higher in cows housed in a shed with a dirty versus clean alleyway, with no significant difference at low daily milk yield. From the study findings, we concluded that certain cow characteristics and comfort measures were associated with SCM and need to be incorporated in education plans for farmers in SDF

Liver Parasites and Body Condition in Relation to Environmental Contaminants in Caribou (Rangifer tarandus) from Labrador, Canada

Over the last several decades, elders and hunters of the Innu Nation in Labrador, Canada, have expressed concerns over perceived declines in environmental health and the integrity of country food, including caribou. The primary objective of this study was to determine links between specific health parameters and contaminants found in caribou from the George River herd. Twenty-seven caribou killed by local Innu hunters between February and December 2001 were evaluated for gross and microscopic pathology, body condition, liver parasitology, and contaminant levels in kidney and fat. Overall, the sampled caribou appeared to be in adequate body condition for the time of year, and no clinically significant lesions were found. Concentrations of selenium, metals (Hg, Cd, and Pb), 20 organochlorine pesticides (HCB, a-HCH, g-HCH, aldrin, dieldrin, methoxychlor, mirex, a- and b-endosulfan, heptachlor, heptachlor epoxide, g-CHL, cis-CHL, trans-nonachlor, and o,p'- and p,p'-DDD, DDE, DDT), and 24 PCB congeners were within the ranges reported for caribou in Canada. In general, contaminant levels were relatively low, with the exception of cadmium in kidneys (geometric mean: 6.5 μg/g wet weight; range: 1.5–44.0 μg/g). Two types of liver parasites were found: the liver fluke Fascioloides magna (prevalence: 78%; geometric mean abundance: 4.2 flukes/caribou) and a tapeworm larva consistent with Taenia hydatigena (prevalence: 50%; geometric mean abundance: 0.6 larvae/caribou). Using multiple variable regression analysis, we found renal concentrations of cadmium to be positively associated, and selenium to be negatively associated, with F. magna abundance.Ces dernières décennies, les aînés et les chasseurs de la nation montagnaise du Labrador, au Canada, ont exprimé des inquiétudes au sujet du déclin de la santé de l’environnement et de l’intégrité de la nourriture provenant de la campagne, telle que le caribou. L’objectif principal de cette étude consistait à déterminer les liens qui existent entre certains paramètres de santé précis et les contaminants se trouvant dans le caribou du troupeau de la rivière George. Vingt-sept caribous ayant été tués par les chasseurs montagnais de la région entre les mois de février et de décembre 2001 ont subi des examens pathologiques macroscopiques et microscopiques, en plus d’avoir été évalués pour en déterminer l’état du corps, la parasitologie du foie et les taux de contaminants dans le foie et le gras. Dans l’ensemble, l’état des corps de caribous échantillonnés semblait adéquat pour cette période de l’année et aucune lésion clinique importante n’a été signalée. Les concentrations de sélénium, de métaux (Hg, Cd et Pb), de 20 pesticides organochlorés (HCB, a-HCH, g-HCH, aldrine, dieldrine, méthoxychlore, mirex, a- et b-endosulfane, heptachlore, heptachlorépoxyde, g-CHL, cis-CHL, trans-nonachlore ainsi que o,p'- et p,p'-DDD, DDE, DDT) et de 24 congénères de PCB s’établissaient dans les étendues signalées pour le caribou au Canada. En général, les niveaux de contaminants étaient relativement faibles, à l’exception du cadmium se trouvant dans les reins (moyenne géometrique : 6,5 μg/g poids humide; étendue : 1,5–44,0 mg/g). Deux types de parasites du foie ont été trouvés : la douve Fascioloides magna (prévalence : 78 %; abondance moyenne géométrique : 4,2 douves/caribou) et un cestode du genre Taenia hydatigena (prévalence : 50 %; abondance moyenne géométrique : 0,6 larves/caribou). Nous avons également réalisé une analyse de régression à variables multiples qui nous a permis de constater que les concentrations de cadmium sont positivement associées et celles de sélénium sont négativement associées à l’abondance de F. magna

Assessment of farmers' compliance in implementing recommended cow comfort changes and their effects on lying time, stall and cow cleanliness within smallholder dairy farms in Kenya

Our study aimed to evaluate farmers' compliance in implementing recommendations of farm-specific cow comfort changes, and the effects of these changes on lying time, stall cleanliness and cow cleanliness using a randomized controlled trial carried out on 100 smallholder dairy farms in Kenya, with 62 and 11 farms remaining in the intervention and control groups, respectively. On the first farm visit, data loggers were attached on lactating cows to determine lying time and questionnaires utilized to collect baseline data. Three days later, stall design and management recommendations were given to the intervention group of farmers orally and in written form. After an average of 39 ± 7 days, data loggers were re-attached, compliance was assessed, and a post-intervention questionnaire was administered to the intervention group on the third visit. Three days subsequent to the first and third visits, data loggers were removed from all cows. Data were analysed in Stata 14.2® using proportion tests and Kruskal-Wallis rank tests to compare cleanliness scores and lying time, respectively. Interaction effects between treatment groups and visits were assessed using multivariable mixed linear and logistic regression models. While 46 of the 62 intervention farmers (74%) made at least one recommended change to cow comfort, 63% of the 324 overall recommendations were implemented. The odds of a recommendation being implemented were significantly higher when:1) major recommendations were given relative to minor recommendations (OR = 6.28); 2) recommendations were related to floor characteristics (floor softness and flatness) in comparison to recommendations related to stall design (OR = 3.14). The odds of compliance were lower on: 1) farms where the farm-hands received the recommendations compared to farms that had the female principal farmer receive the recommendations (OR = 0.01); 2) farms that had recommended changes related to roof, alley and sharps fixes relative to stall design fixes (OR = 0.13). Post-intervention, stall, udder and upper hind-leg cleanliness scores improved significantly (p < 0.0001, p = 0.021 and p = 0.017, respectively) in the intervention farms but not in the control farms. There was no significant difference in lying times between intervention and control farms, with 0.6 and 0.2 h/day increases being recorded in the intervention and control groups, from the 10.9 and 10.4 h/day at baseline, respectively. Giving farm-specific cow comfort recommendations to smallholder dairy farmers in Kenya, and providing them with a participatory role in the formulation and implementation of improvement recommendations ensured good acceptance and a high degree of implementation, and led to a subsequent improvement in cow comfort and cleanliness

Impact of high proviral load on milk production, reproduction and subclinical diseases in dairy cows infected with bovine leukemia virus

IntroductionBovine Leukemia Virus (BLV) prevalence remains high in dairy cattle in North America. Quantifying the proviral load (PVL) in BLV-positive cows can be used to control this disease in herds where BLV is prevalent by focusing culling of high PVL animals to reduce the risk of transmission. The impact of high BLV PVL on dairy cows’ performance is not well established. The objective of this study was to assess the effect of high PVL status on milk production, occurrence of subclinical ketosis or mastitis, or fertility in BLV-infected cows.MethodsTwenty-five herds from the three Maritime provinces in Atlantic Canada were enrolled in this study. BLV infected cows were first identified by individual milk or serum testing. A validated quantitative qPCR was used to quantify the PVL in cows with positive BLV antibody results. Parity, 305-day milk production, annual geometric average somatic cell count, fat-to-protein ratio in milk on the first test post-calving, days in milk at first service, and calving-to-conception interval were collected from DairyComp305 software. Two-level mixed multivariable regression models were used to assess the relationship between BLV PVL and milk production, subclinical mastitis and ketosis and reproduction performance.ResultsHigh PVL was strongly associated with reduced milk production (387 kg and 431 kg) and reproduction performance (calving-to-conception interval lengthened by 50 days and 49 days), and higher odds of subclinical mastitis (Odds ratio = 2.38 and 2.48), when compared to BLVpositive cows with a low PVL and BLV-negative cows, respectively.ConclusionThese results support implementing a control program to prioritize culling high PVL cows

Breast Cancer Risk, Fungicide Exposure and CYP1A1*2A Gene-Environment Interactions in a Province-Wide Case Control Study in Prince Edward Island, Canada

Scientific certainty regarding environmental toxin-related etiologies of breast cancer, particularly among women with genetic polymorphisms in estrogen metabolizing enzymes, is lacking. Fungicides have been recognized for their carcinogenic potential, yet there is a paucity of epidemiological studies examining the health risks of these agents. The association between agricultural fungicide exposure and breast cancer risk was examined in a secondary analysis of a province-wide breast cancer case-control study in Prince Edward Island (PEI) Canada. Specific objectives were: (1) to derive and examine the level of association between estimated fungicide exposures, and breast cancer risk among women in PEI; and (2) to assess the potential for gene-environment interactions between fungicide exposure and a CYP1A1 polymorphism in cases versus controls. After 1:3 matching of 207 cases to 621 controls by age, family history of breast cancer and menopausal status, fungicide exposure was not significantly associated with an increased risk of breast cancer (OR = 0.74; 95% CI: 0.46–1.17). Moreover, no statistically significant interactions between fungicide exposure and CYP1A1*2A were observed. Gene-environment interactions were identified. Though interpretations of findings are challenged by uncertainty of exposure assignment and small sample sizes, this study does provide grounds for further research

2010 Spring ENGR333 Poster 2

The new redundant data center requires that Network Operations Center personnel are able to monitor certain conditions within the data center for the safety of the server equipment. Server equipment will fail if it gets too hot or if the surrounding environment becomes too humid, therefore the baseline instrumentation design must monitor both temperature and humidity in the data center. The system must also be capable of remotely alerting NOC personnel when there is a problem