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Washington State University Dairy News

March 2015 WSU Dairy Newsletter

Amber’s Top Ten Tips: Assessing Dairy Cow Behavior

Cow comfort” and “animal welfare” are two phrases receiving an increased amount of attention from dairy producers across the nation. Have you heard these phrases recently? Do you know what they mean? How do you measure cow comfort? As you consider these questions, let’s start at the beginning: animal behavior. I spent the last seven years working on animal behavior in lizards, horses, goats, and cattle. For the purpose of this article, I will focus on dairy cow behavior. I encourage you to attempt to identify the following ten cow behaviors on your dairy and consider how changes in some of these behaviors may help you identify issues in the herd:

  1. Feeding

    Decreases in the amount of time a cow spends at the feed bunk may indicate metritis, ketosis, or, locomotion disorders.

  2. Isolation

    Isolation behavior (or seclusion from the rest of the herd) may occur prior to calving.

  3. Social

    Cows develop a social hierarchy within a herd. Cows ranked lower in social hierarchy are displaced at the feed bunk more often than cows ranked higher in the social hierarchy.

  4. Estrous

    Restlessness, chin resting on other cows, standing heat, and increases in walking are all behavioral tools used to detect estrus in cows.

  5. Maternal

    Following calving, cows lick their calves to stimulate calf activity and dry the calf’s coat. Cows may also display a flehmen response (elevation of head combined with retraction of the upper lip) towards the calf and amniotic fluids.

  6. Lying

    During the six hours prior to calving, cows will increase their number of lying bouts, but will decrease their overall time spent lying.

  7. Drinking

    Water consumption increases during heat stress conditions, but cows will decrease their time spent drinking prior to calving.

  8. Standing

    One week prior to calving and during the day of calving, cows diagnosed with ketosis increase the amount of time they spend standing.

  9. Stereotypic (repetitive behaviors that hove no obvious function)

    Increases in number of tongue-rolling occurrences within a herd may be associated with restrictive feeding.

  10. Agonistic

    As feeding space at the bunk decreases, the number of aggressive displacements at the bunk increases.


Revisiting Subacute Ruminal Acidosis (SARA)

Subacute Ruminal Acidosis (SARA) is a consequence of our selection for high-producing dairy cattle. To reach their genetic potential for production, these animals need a nutrient dense, high energy diet. Their daily dry matter intake (DMI) is greater than previous average dairy cattle DMI levels. These highly-productive animals are therefore ingesting large quantities of fermentable carbohydrates, which can overwhelm the rumen’s ability to absorb volatile fatty acids (VFAs) and regulate acidity (pH).

Although the definition of SARA can vary, multiple researchers define it as a rumen pH below 5.5 for at least three hours a day. SARA is not rare; one study reported an incidence rate of 26% of mid-lactation and 19% of early lactation cows. It is most common between calving and 150 days of lactation, especially around 90 days as DMI increases with peak milk production. It significantly reduces milk production and components, either directly or indirectly increases culling rates, and can kill cows. Annual industry costs have previously been estimated at $500M to $1B.

Risk Factors for SARA

  • Feeding high dietary levels of rapidly-fermentable carbohydrates (grains, molasses, etc.)
  • Feeding ration by components vs. as a total mixed ration (TMR)
  • Offering few large meals or irregular meals
  • Poorly-mixed TMR
  • Over-mixed TMR
  • Lack of effective fiber in TMR
  • Excessive fiber particle length, resulting in TMR sorting and grain overconsumption
  • Lack of adequate bunk space so not all animals have access to all TMR components
  • Lack of comfortable and sufficient stalls to encourage rumination

Diagnosing SARA

Microscopic image of healthy papillae.
Photo 1. Rumen papillae. These healthy papillae are numerous, long, normal color, and not stunted. They provide the surface area needed for fast absorption of VFAs so rumen pH does not drop excessively. With acute or chronic acidosis, the papillae will be blunted, blackened, missing, or eroded, and VFAs cannot be absorbed effectively. Source: http://arbl.cvmbs.colostate.edu.

All cattle should be monitored closely for signs of SARA up until about day 150 of lactation, when decreasing feed intake reduces their risk. Signs of the condition are vague and subtle, but can include reduced milk production, reduced feed intake, weight loss, lack of cud chewing, milk fat depression, and/or foamy or otherwise abnormal diarrhea that may include intestinal tissue casts. However, some of the most important consequences of SARA may not occur for many weeks. Laminitis (founder) is a common occurrence, and rumenitis from SARA can seed the body with bacteria and result in sole abscesses, sole ulcers, liver abscesses, and even lung abscesses that erode into lung blood vessels and cause the cow to bleed to death.

Rumen pH can be measured in several animals in a group to determine the presence of SARA. Samples should be taken between 6 to 10 hours after the first TMR feeding of the day. Samples taken via stomach tube are often inaccurate, depending on where the sample was taken. A veterinarian can take an accurate sample directly from the rumen. If more than 25% of rumens sampled have a pH < 5.5, SARA is lurking in the group.

Self-correcting Mechanisms

Ruminant saliva contains natural buffers, including bicarbonate. A diet containing sufficient effective fiber stimulates rumination, which increases saliva production and self-buffering of rumen pH. Another self-regulating mechanism is feed intake: as rumen pH decreases and the concentration of osmotically-active particles in the rumen increases, appetite is suppressed—this prevents additional intake of highly-fermentable fiber and gives the rumen time to re-balance pH.

Populations of rumen microbes are highly variable and are determined by pH, feed substrates available, and other factors. Microbes need time to adapt from high fiber dry cow rations to high concentrate lactating rations. A lead time of 3 to 5 weeks is needed to prepare rumens for lactating diets. This will ensure the right microbes are present to digest feeds and regulate the rate of production and consumption of rumen acids (VFAs and lactic acid). Grain feeding results in the production of butyric and propionic VFAs, which stimulates lengthening of rumen papillae. Long and healthy papillae are able to absorb VFAs quickly and moderate rumen pH (photo 1).

Effects of Rumenitis

If the rumen lining is repeatedly exposed to low pH levels (<5.5), it can become inflamed, eroded, ulcerated, scarred, and hyperpigmented; rumen papillae are stunted and lost. The result is reduced absorption of VFAs from the rumen, which further drops pH. This condition is probably painful and reduces feed intake as well. Rumen inflammation causes production of certain proteins and other markers characteristic of inflammatory processes, and their presence is sometimes used to diagnose SARA

Importance of Regular Meals

Irregular feeding schedules, lack of adequate bunk space, prolonged pre-milking or vet check holding times, and other factors that keep cows away from feed can set the stage for SARA. Here’s why: without the continued intake of a high-concentrate ration, rumen pH rises. This can kill certain types of rumen bacteria, particularly those that use lactic acid and help keep pH from falling too low. With less of these bacteria available, the animal is less able to moderate rumen pH when it takes in feed again. Animals that have not had access to the feed bunk for a while often eat an unusually large meal when feed is made available, which also contributes to falling rumen pH.

Low rumen pH decreases the variety of rumen microbes, causing a less stable rumen pH and reducing the animal’s capacity to regulate pH. Below a pH of 5.5, lactate-producing bacteria proliferate and reduce pH even more.

Causes of SARA

  • Insufficient rumen buffering (inadequate effective fiber, DCAD, and/or natural buffers)
  • Excessive highly-fermentable carbohydrates in diet
  • Lack of rumen’s adaptation to a high-concentrate diet

Reducing the Risk of SARA

High roughage/low concentrate rations can eliminate SARA, but they won’t support maximum milk production. Rations should be fine-tuned and not supply more highly-fermentable carbohydrates than needed; contain adequate effective fiber; include buffers such as sodium bicarbonate and the recommended dietary anion-cation difference (DCAD); be re-formulated as needed to adjust for changing dry matter content of different batches of feedstuffs; and possibly include probiotics including yeast and bacteria that use lactic acid.

Corn silage is a known risk factor for SARA. It has variable digestibility and moisture and insufficient long fiber to promote rumination and buffering. It may need to be mixed with additional fiber in the form of dry hay to meet recommended effective fiber and dry matter content in the TMR.

Bunk management is critical to minimizing SARA. Ensure adequate space so all animals have access to the complete TMR, not the dregs that remain from sorting. Check the TMR throughout the day to monitor the degree of sorting that occurs and correct chopping or mixing as needed. Check to be sure the ration formulated on paper is the ration delivered to and eaten by cows. Keep feed in bunks—if bunks are empty, cows that want to eat will have nothing and their rumen pH will not be stable; SARA can ensue.

References

  • Plaizier, J.C., D.O. Krause, G.N. Gozho, & B.W. McBride. 2008. Subacute ruminal acidosis in dairy cows: The physiological causes, incidence and consequences. The Veterinary Journal, 176(1), 21–31. doi:10.1016/j.tvjl.2007.12.016
  • Krause, K.M., & G.R. Oetzel. 2006. Understanding and preventing subacute ruminal acidosis in dairy herds: A review. Animal Feed Science and Technology, 126(3–4), 215–236. doi:10.1016/j.anifeedsci.2005.08.004
  • Enemark, J.M.D. The monitoring, prevention and treatment of sub-acute ruminal acidosis (SARA): A review. 2008. The Veterinary Journal, 176(1), 32–43. doi:10.1016/j.tvjl.2007.12.021

Winter Kill on Grass Fields in Western Washington

Did you notice winter kill on grass fields over the later 2014 – early 2015 time period? If so, the answer may be related to lack of dormancy going into winter period.

Nutrient management is important all times of the year in forage production systems. However, the fall (September) period is the beginning of the annual calendar cycle of adapted grasses, including ryegrass. The grass plant will generate new roots and new growing points in the fall period only to shed those roots during the winter. If grasses are not allowed to transition into a dormancy state in the late fall, such as late October to mid-November, and grass growth remains active then the probability of winterkill increases.

Nutrients such as N in early fall may contribute to continued active fall growth, delaying fall dormancy. So, if we start with a low stubble harvest height in the final cutting, compound the plant mechanism of lower grass sugars and active grass growth from higher soil N availability, then add one below normal, very cold Arctic blast, we have the perfect storm for winterkill. This happened to many grass producers in 1988 resulting in thousands of westside acres of perennial grasses dead. This perfect storm was repeated in the fall and early winter of 2014. As our crops are emerging from winter dormancy and into spring greenup, the results of that perfect storm are clear.

Perennial and annual ryegrasses store the highest amount of sugars in the stem and basal (crown) tissue of any cool-season grasses grown in the PNW. We expect the range of these fructosan sugars to range above 20% to nearly 30%. Fructosan sugars can be thought of as the anti-freeze in these highly productive and high quality westside grasses. Even though the sugar may differ among grass crops, the net result is similar, increased winterhardiness and rapid regrowth after harvesting. Unlike alfalfa and other legumes where the sugar (starch in this case) is stored in the crown and tap root, cool-season grasses store sugars in the basal 3 to 4 inches of the stubble.

Grazing or cutting with machines to close to the ground will remove essential sugars for growth and survival. This is not just in the final fall harvest but all cuttings over the growing season. What sets up the critical fall grass establishment period is the summer. Measure sugar concentrations in the summer and you’ll find them lower than at any time of the growing season. In the fall, sugar levels should be at their highest, not lowest. Another important characteristic in grass management is the inverse interrelationship between nitrogen (Crude Protein) and sugar concentrations. As CP increases sugar concentrations decrease. Decreasing stored sugars reduce winterhardiness in tame cool-season grasses, such as ryegrass. Nutrient management is important all times of the year in forage production systems.

Thus, we never recommend either harvesting or grazing cool-season grasses less than three-inches. For timothy and a couple other grasses, never less than four inches. Thus, lower summer cutting heights reduce sugars proceeding into September, not a prime situation when the plants essentially establish productive potential at this time for the following year. Secondly, to increase September and fall sugar storage in the stubble and in the above ground growth, the plants must conserve sugars to transition into a state of winter dormancy.

On the westside this dormancy level does not need to be as severe or deep as Minnesota and the upper mid-west for winter survival, but westside grass winter dormancy is important. Third, nutrient applications of manure or fertilizer N may prolong fall growth, reduce sugar concentrations and inhibit winter dormancy. Timing of transition is dependent upon fall temperatures, soil temperatures, fall rains, soil moisture status, grass genetics and health of the plant.

Fall is not a time when producers can slack off on their grass management, actually the opposite is true. Fall is when you need to do the best possible job to reduce winterkill injury and enhance rapid, early spring growth.

Finally, as grasses emerge in the spring, they are often lower in sugars than when they entered winter dormancy. Avoid early turnout on to pastures until atl east six to eight inches of growth have been attained. Reduction of stands can occur in summer, when grasses are shedding roots when plants do not have enough sugars for high respiration rates in summer heat then placing the plant in a less than productive state entering the critical fall period.

December 2014 WSU Dairy Newsletter

Greetings and Welcome to Our New Look for the WSU Dairy Newsletter

With this issue of the WSU Dairy Newsletter, we debut a new system for managing our Newsletter. Please provide any feedback in regard to the format and usefulness of this publication to Joe Harrison at jhharrison@wsu.edu.

Dr. Amber Adams-Progar
Dr. Amber Adams-Progar
In addition to the change in the Newsletter format, we would also like to welcome Dr. Amber Adams-Progar, Dairy Extension-Research faculty in the Department of Animal Sciences at WSU Pullman. Amber joined the faculty in June of 2014 and will focus on Animal Well-Being and Calf Management, as well as being a resource for general dairy extension needs in the state. She can be contacted at amber.adams-progar@wsu.edu or 509-335-0673.


Dr Amber Adams-Progar’s Top Ten Tips: Calf Management

After spending the last year and a half working with about 40 dairy farms, and putting over 60,000 miles on the rental car, I have seen a wide variety of calf management strategies. Some ideas were instant successes, some were close to success, and others just flat out failed. When evaluating your calf management practices, keep these 10 things (listed in no particular order) in mind:

  1. Calving area

    Avoid housing sick cows in the calving pen and keep the calving area as clean as possible to limit a newborn calf’s exposure to pathogens.

  2. Location, location, location

    Prevent the transmission of disease from older cattle to calves by housing calves away from older cattle and removing nose-to-nose contact between the two age groups.

  3. Cleanliness of calf environment

    Cleaning the pen/hutch and buckets after each calf decreases bacteria exposure from calf to calf.

  4. Bedding

    Choose bedding that keeps calves clean, but doesn’t irritate the respiratory system.

  5. Ventilation

    Remember to test airflow at calf height and prevent drafty areas that may cause a calf to become chilled.

  6. Water

    Access to clean water during the day improves calf gain and reduces the effects of heat stress.

  7. Nutrition

    Providing sufficient amounts of milk and starter feed that are free of pests, including flies, promotes higher feed intake and better health.

  8. Lighting

    Ensure the natural or artificial lighting is plentiful so calf care managers can easily observe calves for signs of illness.

  9. Colostrum

    Quality of the colostrum should be measured using a Colostrometer or Brix refractometer for assurance that the calf will receive adequate immunity.

  10. Health records

    Maintaining calf treatment records reduces errors in treating calves and reveals calf disease patterns that can be addressed with your veterinarian.


Feeding Pasteurized Waste Milk to Calves

If you have a steady supply of waste milk, you might consider pasteurizing and feeding it to calves. Many studies show this can result in cost savings, improved calf health and increased growth rates.

Definition of Waste Milk

Waste milk includes colostrum, transition milk, high cell count milk, milk withheld due to antibiotic treatment and mastitic milk. It isn’t recommended to feed raw or pasteurized milk that is overtly abnormal or milk with extremely high bacterial loads. Also, because of the possibility of antibiotic residues in waste milk from treated cows, it shouldn’t be fed to animals being raised for meat; this possibility might also discourage some producers from even feeding it to replacement heifers.

Hows and Whys

Milk replacer costs continue to rise and it is not cost-effective to feed salable milk to calves when milk prices are high. Feeding waste milk can meet calves’ nutritional needs by using an otherwise-discarded product. Feeding raw waste milk is not recommended due to its potential to contain a variety of disease-causing organisms (see box).

Pathogens of Concern in Raw Milk

  • Mycobacterium avium subsp. paratuberculosis
  • Salmonella species
  • Mycoplasma species
  • Listeria monocytogenes
  • Campylobacter species
  • Mycobacterium bovis
  • Enterobacter species
  • Staphylococcus species
  • E. coli

Pasteurized waste milk (PWM) greatly reduces the pathogen load to which calves are exposed, but not to the complete reduction achieved through the use of well-managed milk replacers. Growth rates on PWM exceed those of traditional milk replacers but are similar to those of new higher-quality milk replacers. The table below compares the nutritional content of milk, waste milk and milk replacers on a dry matter basis.

Nutritional content of milk, waste milk and milk replacers on a dry matter basis
Source Protein Fat
Milk 24 to 27% 28 to 36%
Waste milk 25 to 30% 25 to 35%
Milk replacer 18 to 29% 15 to 20%

Economic analyses found that feeding PWM was cost effective when at least 23 calves were fed in one study and 60 in another. This indicates that PWM feeding is probably not cost effective for smaller operations.

It is recommended to collect and store waste milk in a dedicated bulk tank so the pooled milk can make the nutritional content more uniform and dilute any milk containing antibiotics. Waste milk should be cooled to at least 45°F before and after pasteurization and protected from contamination after pasteurization. This bulk tank should be cleaned and sanitized just like the salable milk tank.

Advantages and Disadvantages

Overview of the potential advantages and disadvantages of feeding PWM to calves.
Advantages Disadvantages
  • Probable feed cost savings, especially in comparison to high quality commercial milk replacers.
  • Compared to raw milk, improved calf health (especially scours and pneumonia) due to reduced exposure to disease-causing agents.
  • Faster growth due to higher nutritional content of waste milk vs. most milk replacers.
  • Effective pasteurization kills up to 99% of bacteria and deactivates toxins
  • Beneficial use of otherwise-discarded products.
  • Various immune factors in whole milk may survive pasteurization and provide protection not available via milk replacer.
  • Cost of pasteurizer and energy to operate it.
  • Increased trained labor for managing, monitoring and cleaning pasteurizer (if not self cleaning).
  • Need to cool and store milk ASAP before and after pasteurization.
  • Dependence on regular volume of useable waste milk.
  • Pasteurization process can fail so must be monitored routinely.
  • Variable nutritional content of batches, especially in small herds.
  • Potential feeding of low-level antibiotics to calves.

Pasteurization Options

Most pasteurizers are either standard batch pasteurizers (commercial or homemade) or commercial high temperature/short time (HTST) continuous-flow machines. Batch units heat a batch of milk to 145°F for 30 min.; the milk is cooled and fed. In HTST systems, milk is rapidly heated to 161°F for 15 sec., then cooled to be fed or held. These units pasteurize milk more quickly, thoroughly and dependably than batch systems, but they are harder to clean unless automated. The price of commercial units continues to drop with increasing acceptance on farms. Colostrum can be pasteurized, but it must be done at a lower temperature for a longer time so immunoglobulins essential for neonatal calf health will not be destroyed; 140°F for 60 min. is recommended.

Conclusions, Problem Solving and Cautions

As you can see, each farm needs to weigh the pros and cons of feeding milk replacer, raw waste milk, salable raw milk or PWM to calves. The ultimate decision is a balance between disease control, feed costs and labor; this decision can fluctuate with market price changes. Here is a summary of suggestions and considerations regarding the feeding of PWM:

  • Do not use heavily contaminated waste milk or visibly mastitic milk for calves.
  • Wait to feed PWM until calves are over one day old.
  • Avoid switching calves between PWM and milk replacer. Estimate expected upcoming waste milk volumes and assign calves to either PWM or milk replacer feeding if there isn’t enough PWN for all. If calves must be switched, try to do so after calves are at least three weeks old.
  • If waste milk volume is low, high somatic cell count milk could be included.
  • Don’t collect milking system flush water with waste milk to be fed to calves; this will dilute milk nutrients excessively.
  • Do not consider pasteurization a shortcut to sanitation, milk handling and best feeding practices. All milk feeding equipment (buckets, bottles, nipples, etc.) still need to be cleaned and sanitized or the disease-reduction benefits of pasteurization will be lost.
  • Agitate and mix stored batches close to feeding time or fat will separate from milk, causing some calves to receive too little fat and others too much.
  • Because pasteurization greatly reduces pathogen loads in milk but does not sterilize it, it is still recommended to house calves individually to prevent suckling and possible disease transmission.
  • Employee training and understanding of pasteurization is essential.
  • Routinely monitor the pasteurization process through temperature checks and milk cultures for quality testing (goal: standard plate count <20,000 cfu/ml).
  • Reminder: calves fed PWM.
  • may ingest antibiotics in milk from treated cows, so withholding periods must be observed.
  • Suggestion: visit with producers who are successful with waste milk pasteurization systems to observe the process, ask questions and learn from their experience.

Postscript

On a related note, a spreadsheet that helps decide when it is more cost effective to feed milk replacer vs. salable whole milk is available from Penn State Extension. If you do not have access to the internet, contact me and I’ll be happy to work through the spreadsheet with you.

Useful links for additional information


Western Dairy Management Conference

March 3 – March 5, 2015 | Reno, NV

John Ascuaga’s Nugget
1100 Nugget Avenue
Reno, NV 89431
800-648-1177

Conference Schedule

Registration

  • Tuesday, March 3: 10:00 AM – 5:30 PM
  • Wednesday, March 4 & Thursday, March 5: 6:30 AM to 5:00 PM

Seminar Schedule

  • Tuesday, March 3: 1:30 PM – 5:30 PM
  • Wednesday, March 4 & Thursday, March 5: 8:00 AM – 5:40 PM

Opening Reception

  • Tuesday, March 3: 5:30 PM – 7:00 PM

Registration

Go to the Western Dairy Management Conference website and complete your registration online. You can also register by mail. Complete and return the attached registration form (one form PER PERSON) along with payment. The conference fee is $390 per person if postmarked by February 1, 2015.

After February 1 the registration fee is $425. Student Registration is $200.


Waste to Worth 2015

March 30 – April 3, 2015 | Seattle, WA

You are invited to attend the International Conference on Livestock & Poultry Environmental Quality

A national network of agri-professionals addressing issues related to air, water, soil, and climate.

Details on registration, hotel accommodations, sponsorship, vendor display registration, program, and tours a the Waste to Worth conference website.

Who should attend?

  • Extension agents & specialists
  • Farmers & producers
  • NRCS staff
  • Technical service providers
  • Consultants
  • Regulatory & policy advisors
  • Commodity groups
  • Environmental NGOs
  • Technology providers
  • Researchers
  • Vendors