The average Class III milk price for January to April of 2018 was slightly above $14 per hundredweight, well under the cost of production. That has forced dairy farmers to seek management strategies to increase income, cut costs or both.
Milk quality is one area in which dairy producers have the most control. Besides being the right thing to do, producing high-quality milk and refining mastitis treatment strategies can provide economic benefits on both the income and cost sides of the ledger.
Implementing strategies to reduce clinical and subclinical mastitis levels can lead to a lower level of mastitis-related cow culling and pave the way toward earning available milk quality premiums. Newer mastitis management strategies like pathogen-based treatment and selective dry cow may also have a positive economic impact on your dairy operation.
Strive to earn premiums
Most milk processors pay quality premiums for milk, and some implement deductions if the milk fails to meet minimum quality standards. Premiums for high-quality milk are usually based on somatic cell count (SCC) and various bacteria counts: standard plate count, preliminary incubation count and lab pasteurized count.
For example, some processors may pay 25 cents per hundredweight for milk with an SCC less than 200,000 cells per milliliter, with additional premiums for milk with an SCC of less than 150,000 or less than 100,000 cells per milliliter.
Milk standard plate count usually has to be below 10,000 colony-forming units per milliliter to achieve a premium payment. If applicable, minimum quality levels for preliminary incubation count or lab pasteurized count differ by processor.
Earning premiums for superior milk quality should be part of the management strategies implemented by all dairy producers. Achieving a milk premium or attaining the next level of premium may provide substantial financial benefits.
For example, a 1,000-cow dairy farm averaging 80 pounds of milk per cow per day could earn an additional $4,800 to $12,000 monthly for premiums ranging between 20 and 50 cents per hundredweight, respectively.
Economical treatment strategies
The common way to manage mastitis is to treat every cow displaying clinical mastitis with an intramammary antibiotic. However, today we know this is not the best way to manage mastitis. Pathogen-based treatment is one way to economically manage mastitis to earn additional milk quality premiums.
To manage mastitis, a producer has to know what they are trying to manage: In other words, you have to know what organism or organisms is causing the mastitis. Pathogen-based treatment requires collecting and culturing a milk sample from the quarter exhibiting clinical mastitis.
Samples can be submitted to a milk quality lab or cultured on-farm. Results from the aerobic culture can be identified within 18 to 24 hours after plating, allowing rapid treatment decisions.
The advantage to pathogen-based treatment is: Only the organisms that respond to mastitis treatment are treated with an intramammary antibiotic. Given that approximately 25 to 35 percent of mastitis cultures are negative for the presence of bacteria, there is no reason for treatment. This means there can be a 25 to 35 percent reduction in intramammary antibiotic usage.
Also, there are mastitis-causing organisms like E. coli (which the cow can self-cure) or T. pyogenes that do not respond to treatment. Depending on the mastitis-causing organisms within a herd, it is possible intramammary antibiotic usage can be reduced by 50 to 60 percent or more.
In addition to reducing overall antibiotic use, the bigger economic advantage to pathogen-based treatment is the production of more salable milk. When a cow has a case of mastitis, the milk or quarter will be abnormal (and not salable) for four-and-a-half to five days.
Some intramammary mastitis treatments may require treating a cow for two to eight days and then withholding milk for another 1.5 to eight days after the last treatment.
A Cornell University study showed cows on a pathogen-based treatment program had three more days of salable milk than cows treated with a blanket intramammary antibiotic program.
In terms of reduced antibiotics as well as the increase in salable milk, pathogen-based treatment equated to a $30 savings per cow on an annual basis (including sampling/processing fees) as compared to blanket treatment of all mastitis cases with an intramammary antibiotic. For every 1,000 cows, pathogen-based treatment can lead to $30,000 in annual savings.
Since pathogen-based treatment promotes prudent use of antibiotics and is financially beneficial to dairy producers, it is something that should be considered by all dairy managers – and can be started at any time.
A newer management strategy related to milk quality is selective dry cow therapy. Historically treating each quarter of every cow with a long-acting antibiotic was likely the right thing to do when the prevalence of contagious organisms like Strep ag. and Staph aureus were very high and the prevalence of subclinical infections at dry-off was very high.
As an industry, blanket dry cow therapy has been widely adopted, with about 90 percent of cows treated with an intramammary dry treatment at dry-off.
However, in the last couple of decades, management of lactating and dry cows has improved significantly to the point fewer animals enter the dry period with a mastitis infection. Recent studies show only 10 to 25 percent of cows have cultural bacteria at dry-off.
Implementing a selective dry cow therapy program requires knowledge of lactating cow data to help differentiate whether a cow is low-risk for an infection and doesn’t require an intramammary dry treatment or high-risk for an infection at dry-off and requiring an intramammary dry treatment.
A selective dry cow study at Cornell University defined a low-risk cow at dry-off as the following:
1. Last test day SCC at 200,000 cells per milliliter or less
2. Average of last three test days SCC at 200,000 cells per milliliter or less
3. One case of mastitis during lactation or less
4. No current signs of mastitis
The Cornell study determined 65 percent of cows were identified as low-risk. These cows were only administered an external teat sealant, whereas high-risk cows were treated with an intramammary antibiotic and an external teat sealant.
When comparing low-risk cows which did receive antibiotics at dry-off to those low-risk cows that did not receive antibiotics, there was no difference in milk production, SCC linear score, clinical mastitis and culling, meaning selective dry cow therapy was just as good as blanket dry cow therapy as it related to milk production, udder health and culling.
The advantage to selective dry therapy is a greater than 60 percent reduction in dry cow antibiotics. Depending on the price of the intramammary dry cow treatment, that reduction could lead to a savings of $6 to $10 per cow.
Selective dry cow therapy is not a management strategy that can simply be implemented without a meticulous review of cow records and an understanding of what management is required to make the program work successfully.
Superior milk quality will provide an additional financial resource for the dairy operation. The added benefit of producing high-quality milk is: Cows with low SCC will be more profitable in other ways, reducing the risk for clinical and subclinical mastitis, thereby reducing the costs of treatment and milk withheld from the tank.
The impact of good milk quality has further-reaching effects than just the mammary gland. Inflammation of the udder may also negatively impact reproduction. Promoting superior milk quality will indirectly promote a superior or high-quality work environment with more healthy cows and less special-needs animals to manage, too.
As with all milk quality goals, it is highly recommended you consult your veterinarian and milk quality expert before implementing any new management strategies that could have unforeseen negative consequences if not managed properly. 
Mike Zurakowski is Eastern laboratory director and a senior extension associate with Quality Milk Production Services. Email Mike Zurakowski.
Quality Milk Production Services is a program of the Animal Health Diagnostic Center in the department of population medicine and diagnostic sciences within the college of veterinary medicine at Cornell University.
It offers a variety of services, notably on-farm evaluations of management and equipment and whole-herd milk cultures, through its laboratories in Ithaca, Warsaw, Cobleskill and Canton, New York.
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Rick Watters
- Western Laboratory Director and Sr. Extension Associate
- Quality Milk Production Services
- Email Rick Watters
