William J. Goodger

Use of metabolic profiles in dairy cattle in tropical and subtropical countries on smallholder dairy farms.

Metabolic profile testing has generally been used as part of a multidisciplinary approach for dairy herds in temperate climates. Our goal was to evaluate the effectiveness of the technique for identifying constraints on productivity in small herds in environments less favorable for milk production. Metabolites tested were chosen for stability in the sample after collection of blood, ease of analysis and practical knowledge of the meaning of the results. Blood levels of five different metabolites in low-producing dairy cows belonging to smallholders in tropical and subtropical environments were measured. The study involved 13 projects with 80 cows in each, carried out in six Latin American, six Asian, and one southern European countries. Data were also collected on feeding, body condition score (BCS) and weight change, parasitism, and reproduction. In Chile, Mexico, Paraguay, Philippines, Uruguay, and Venezuela, globulin levels were high in > 17% of cows sampled on each occasion. Globulin levels were also high in Turkey and Vietnam on one or more occasions. In Paraguay, 49% of cows had high globulin levels at two to three months after calving. These results suggest that inflammatory disease was present to a potentially important degree, although this was not always investigated and not always taken into account. In all countries except Mexico and Venezuela, high beta-hydroxybutyrate (BHB) levels before calving in many cows highlighted the presence of condition loss in late pregnancy, an important potential constraint on productivity and fertility. Fewer cows showed high BHB levels in lactation, whereas change in BCS and weight was more sensitive for measuring negative energy balance. Urea concentrations were low in only small numbers of cows suggesting that dietary protein shortages were not common. Albumin values were low mainly in cows where globulin values were high and, hence, did not generally provide additional information. The exception was in China where pregnant yaks over winter had high BHB and low albumin values, suggesting that they were seriously underfed. This observation stimulated a successful nutritional intervention in the following winter. Inorganic phosphate values were within the reference range in most countries a majority of the time suggesting, contrary to expectation, that this mineral was not commonly a constraint. The use of metabolic profile testing proved valuable in drawing attention to important potential constraints on productivity in dairy cows in tropical and subtropical environments and in confirming those which were not.

Participatory rural appraisal to identify needs and prospects of market-oriented dairy industries in Bangladesh

We assessed resources, challenges and prospects of the dairy industries in four districts of Bangladesh (Mymensingh, Satkhira, Chittagong and Sirajganj) with the participation of 8 to 12 dairy farm families in each district. We used ten participatory rural appraisal (PRA) tools, namely social mapping, semi-structured interview, activity profiles, seasonal calendar, pie charts, mobility diagram, matrix ranking, preference ranking and scoring, system analysis diagram and focus group discussion in 57 PRA sessions from September through October 2002. Dairying contributed more to family income (63 to 74%) and utilized a smaller portion of land than did crops. Twenty seven to 49% of cattle feed is rice straw. Only Sirajganj and Chittagong had limited, periodic grazing facilities. Fodder (Napier; Pennisetum purpureum) cultivation was practiced in Sirajganj and Satkhira. Fodder availability increased milk production and decreased disease occurrence. Friesian crossbred cows were ranked best as dairy cattle. The present utilization of veterinary and AI services was ranked highly. Farmers outside the milk union desired milk purchasing centres as the most required service in the future. They identified veterinary and AI services as inadequate and desired significant improvements. The PRA tools effectively identified resources, constraints, opportunities and farmers’ perspectives related to the dairy industries in Bangladesh.

Effect of milk sample collection strategy on the sensitivity and specificity of bacteriologic culture and somatic cell count for detection of Staphylococcus aureus intramammary infection in dairy cattle

Four milk sample collection strategies for bacteriologic culture and identification of bovine intramammary infection due to Staphylococcus aureus were evaluated. Milk samples were collected at 24 h intervals from 245 lactating mammary quarters of 62 cows from one commercial dairy herd on 6 successive days. A total of 1470 quarter milk samples were available for study. Based on the bacteriologic culture results of all six quarter milk samples, each quarter was classified as infected with or free of S. aureus. The case definition used to establish the ‘gold standard’ was the isolation of two or more colonies of S. aureus on two or more occasions from the six quarter milk samples obtained from a given mammary quarter. The probability of a false-negative classification of a mammary quarter using all six culture results was estimated to be less than 0.0046, while the probability of a false-positive classification was less than 0.0004. Twenty-two quarters from 16 of 62 cows had S. aureus intramammary infection. Inocula (0.1 ml) for bacteriologic culture were prepared in the laboratory from quarter milk samples to represent alternative strategies for milk sample collection on farms. Sensitivity and specificity of detection of S. aureus-infected mammary quarters and/or cows was then determined. The accuracy of somatic cell counts for the same purpose was also determined for several cut-off values. The range of sensitivity values for bacteriologic culture and SCC were 91–100% and 54–95%, respectively. The range of specificity values for each test method ranged from 97.6 to 100% and from 81 to 83%, respectively. Bacteriologic culture, using any of the sampling strategies examined, had high specificity ( > 98%) and relatively high sensitivity ( > 91%) for identifying S. aureus intra mammary infection (IMI). However, there was a great difference in the number of culture attempts necessary to achieve this accuracy which would influence a dairy farm managers choice of which type of milk sample collection strategy to use.

A linear programming assessment of the profit from strategies to reduce the prevalence of Staphylococcus aureus mastitis

We used a linear programming model to estimate the financial returns to a Staphylococcus aureus testing and control program over a 1-year period for a 100-cow herd, with a 8636-kg rolling-herd average. Six tests, which vary in sensitivity from 0.80 to 0.98 and specificity of 0.99, were examined in simulated herds with 10, 20 and 30% prevalence of S. aureus infection. Sensitivity of these results to a range of assumptions regarding rolling-herd average, milk price, somatic cell-count premium, and cost and cure rate of dry treatment were examined to determine the profits from the program. The profits of a control program are most dependent upon prevalence, cell-count premium, and cost of dry treatment. In our simulation for a 100-cow herd, a testing and control program appears to cost less than US

A model to determine sampling strategies and milk inoculum volume for detection of intramammary Staphylococcus aureus infections in dairy cattle by bacteriological culture

10 per cow per year, and pays for itself within 1 yr, except under the lowest prevalence and most-adverse conditions (low yield, high cost of dry treatment, or low SCC premium.

Methods for conducting an economic opportunity survey in smallholder dairy farms

Abstract A model was developed to evaluate the effects that methods of obtaining milk samples and culture inoculum volumes had on the sensitivity of microbiological culture to detect Staphylococcus aureus intramammary infections (IMI). An assumption was made that milk from mammary quarters infected with S. aureus only contains bacteria intermittently. A modified sine wave function was used to model this intermittent shedding pattern. Specifications for the components of the shedding cycle used in this function were based on quantitative culture results from 54 experimentally infected S. aureus quarters, sampled daily for a period of 30–49 days. The components of the shedding cycle were length in days, peak number of CFU shed per milliliter of milk, and length of time in the cycle when no shedding occurred. These components were used to estimate the models predicted distribution of S. aureus CFU ml −1 milk when individual quarter milk samples were cultured for S. aureus . The sensitivity of culture for several sampling methods was then calculated. The model predicted that culture of a single quarter milk sample had a sensitivity ranging from 60 to 87% for detection of S. aureus IMI depending on inoculum volume. Quarter milk samples taken on day 1 and repeated either on day 3 or day 4, and cultured separately using 0.1 ml of milk for culture inoculum, were predicted to have sensitivities of 90–95% and 94–99%, respectively. Other milk-sampling strategies examined included culture of a composite milk sample (equal-volume mixture of milk from four separate mammary quarters ) and pooled milk samples in which samples from different milkings (either quarter or composite samples) were mixed together and then cultured. The range of predicted sensitivities of these other sampling strategies was 30–97%. Factors having the greatest impact on the sensitivity of culture, in order of importance were: the type of milk sample, the volume of milk cultured, and the time interval between repeated milk sample collection strategies.

Development of a database management/analysis system for field research activities within a coordinated research project.

A form was developed for on-farm use to collect data on dairy cow inventory, animals born, died, and sold, milk consumed and sold, and feedstuffs. Using these data, ten herd management indices are calculated in a spreadsheet. These data are gathered from multiple farms in an area and are summarized to develop herd target or benchmark values. Economic opportunities for achieving target performance at the individual farm level are calculated for five of the indices. This Economic Opportunity Survey has been used to develop regional performance benchmarks and to help individual farmers identify areas for improvement and opportunities for future intervention.

Corrigendum to "a linear programming assessment of the profit from strategies to reduce the prevalence of Staphylococcus aureus mastitis" [Prev. Vet. Med. 33 (1998) 183-193].

There are several ways a database/analysis system can assist a scientist engaged in field research. Specifically, it can assist the scientist with accurate data collection and more rigorous data analyses. The database management portion of this system allows accurate data collection and provides easy data entry through the use of forms. In addition, it can provide the scientist with structured methods of error checking data entry and checking for implausible values and false zeros. The system can also assist the scientist with the organization of the data and provide easy methods of sorting, grouping, and selecting data for analysis. Data can then be exported to a data analysis program where the first step is data validation. A menu of analyses using examples from the coordinated research project (CRP) are demonstrated using statistical methods that test continuous and categorical data.

Diagnostic Methods for the Detection of Subacute Ruminal Acidosis in Dairy Cows

We used a linear programming model to estimate the financial returns to a Staphylococcus aureus testing and control program over a 1-year period for a 100-cow herd, with a 8636kg rolling-herd average. Six tests, which vary in sensitivity from 0.80 to 0.98 and specificity of 0.99, were examined in simulated herds with 10, 20, and 30% prevalence of S. aureus infection. Sensitivity of these results to a range of assumptions regarding rolling-herd average, milk price, somatic cell-count premium, and cost and cure rate of dry treatment were examined to determine the profits from the program. The profits of a control program are most dependent upon prevalence and cell-count premium. In our simulation for a 100-cow herd, a testing and control program results in a profit ranging from US

A Comparison of On-Farm Methods for Estimating the Dry Matter Content of Feed Ingredients

1.50 to US