The bovline vol5 is

From the desk of Angela M. Daniels, DVM Circle H Animal Health LLC & CAVL Diagnostics [email protected] www.circlehanimalhealth.com Does High SCC in Milk Constitute a Human Health Risk? the NMC (old name National Mastitis Council) is an organiza- Six speakers spoke on a variety of topics teurization alone is not the final solution for the during this preconference seminar. Like control of food borne pathogens. most organizations involved in educating While Johne’s disease does not cause a direct their membership, food safety continues increase of somatic cells, it is shed in the milk. to be topic on programs for good reason. Judy Stabel gave a description of Crohn’s dis- ease in humans and discussed it’s recent claim to Steve Oliver from the Univ of Tennessee be linked to Johne’s disease in cattle. A study in resource for information about milk quality. gave a detailed overview of dairy food 1996 suggested that viable Paratuberculosis safety. While this paper did not discuss (causative agent of Johne’s disease) were present control measures for dairy cattle zoonotic in pasteurized milk. This raised obvious con- disease, it is an excellent resource for un- cerns about the effectiveness of pasteurization derstanding the prevalence , significance conditions to inactivate this organism. This set of these papers, contact us and we will email or send them to off a number of additional studies on the topic. trary to our beliefs, the risk of foodborne Most studies agree that a very small percentage illness in the U.S. has markedly increased (<1 percent) of the organism may survive pas-over the last 20 years. The primary rea- teurization using the holder or HTST methods. sons for this is that more meals are con- So pasteurization successfully reduces but does sumed outside the home and consumers not eliminate this organism in milk. Johne’s is demand fresh fruit and vegetables year known to be shed in the feces and milk of in- round increasing the amount of produce fected cows and the prevalence of Johne’s is imported. Cattle are known carriers of escalating in the U.S. In addition, producers Salmonella, Campylobacter and Shiga-toxin suffer reduced milk production, infertility and producing E. coli. Along with Listeria, premature culling due to Johne’s, all which effect which is found in the environment, these profitability. Combined with the potential link between Johne’s and Crohn’s disease, producers though pasteurization is regarded as an are urged to join their state control programs to effective method to eliminate foodborne slow the spread of infection and thus human pathogens and other bacteria in milk, an exposure to this disease. increasing number of reports on detection Joe Hogan provided a summary of research of these pathogens in fluid milk and ready- regarding human health risks and high SCC. to-eat dairy products indicates that pas- Consuming milk with high SCC does not pose direct, specific health risks to humans. But there is a relationship to high SCC and poor farm hy- • w w w .n m c on l in e. o r g — • w w w . u w e x . e d u / giene, antibiotic residues and presence of patho- genic organisms and toxins in milk. These rela- tionships offer insight into the potential increase Resources “World’s Best • www.uwex.edu/uwmril— in food safety risk factors to consumers when high SCC milk is marketed. Most reports indi- cate that lowering limits of SCC will positively • w w w . d q a c e n t e r . o r g — • www.foodscience.cornell influence acceptability and suitability of milk as measured by improved safety, milk quality and value added products. In the EU, safety, suitabil- ity and consumer’s acceptance play compara- • d r i n c . u c d a v i s . e d u — tively important roles as driving forces for low-ering SCC. To Strip or Not to Strip—That is the Question! Four good papers were presented on managing the milk parlor. Jeffrey Rushen talked the treatment about acute stress and handling during milking. Summarizing several studies, he found & diagnosis of that there is a large difference between dairy farms in the way that cattle are routinely handled. Additionally cows’ fear of people and milk yield are affected by the way cows are handled indicating that there are significant economic costs associated with this par- ticular welfare problem. Jim Cullor outlined the evidence based role of fore-stripping. It is outlined in the PMO in the U.S. that “.abnormal milk shal be milked last or in special equipment and discarded” section 7 item 1r. Another section regarding milking states that “.flanks, udders, bel ies and tails shal be free from visible dirt and the udders and teats shal be clean and dry before milking”, section 7 item 13r. So these sections clearly indicate that we must milk a clean, dry, presanitized udder and we are not allowed to put abnormal milk into the bulk tank and offer it for sale. Internationally, the same principles exist. David Reid provided information about on-farm evidence of the role of fore-stripping. While it is tempting to base decisions of fore-stripping on cows milked per hour, a better monitor is milk produced per stall per hour. The goal for 2x herds is 150 pounds per hour and 3x herds is 120 pounds per hour. This monitor allows for the output differences between spending less time in a prep and having a lag time from unit attachment to milk letdown to spending more time in a prep and having better milk flow per unit of time. Overmilk- ing, either at the beginning or end of milking, is an important factor that effects the milkability of a cow. The only studies done on differences of parameters between strip- ping and not stripping are on herds that previously stripped. Many believe the data is potentially biased for this reason but both studies conclude that milk yields are the same but forestripping decreased average unit on time, increased peak milk flow and overall flow rate average. One U of Wisc researcher argued in a Q & A discussion that the re- sults were not biased because they have data showing cows respond very quickly to changes in their routine and data taken during a “transition time” (of moving a cow from stripping to not stripping) compared to study data did not differ. John Smith provided a good paper on overall parlor management and economic considerations. Every manager should read this paper! He suggests the decision of forestripping is not the same in every herd and is dependent upon our goals. He reviewed options for milking procedures and intramuscular ampicillin group. routines in herringbone, parallel and rotary parlors, advantages and disadvantages of mini-Cures were defined as no growth mal and full milking routines and outlined an economic analysis of these ment with systemic ampicillin in conjunction with an intramam- Despite being in the “Information Age” where we often have more data than we know what to do with, this is one area that the speaker remarked is “.still witchcraft”. The evolution of liners from the first double action teat cup in 1878 that used a rubber liner to today’s version with synthetic rubbers and varied formulation allowed there to be many different types to choose from. Among the variables are means of manufacturer (extrusion or molding), dimensions of the main sections (mouthpiece, barrel and short milk tube), option to re-tension or not, composition of milk liner and others. The variety of liner types that have been marketed worldwide runs into thousands of models with hundreds still available today. It is a confusing part of any supplier’s catalogue to find the variety of sizes and shapes offered. These are combinations of shape x size x material. So liners certainly do differ and therein lies a problem for manufacturers, suppliers and customers. Liners have a mouthpiece lip di- ameter of 18 to 26 mm, a barrel bore diameter of 18 to 28 mm, an effective length of 90 to 164 mm and a short milk tube diameter of 7 to 12 mm with barrel cross sections that may be round, oval, triangular or square. The barrel walls may be parallel or tapered and possibly rubber circularly or longitudinally. Liner development appears to have been “pulled” by best practice and optimization to meet particular commercial pressures. Evidence that development has been “pushed” by understanding of actions and predic- tions of effects is less common. Several attempts to model liner movement and forces have been made with limited success. The best advise the speaker, J. Eric Hillerton, had to offer was to stay with the design you have chosen unless there are problems. A mix

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