Fresh cows can be especially vulnerable to a variety of illnesses, so it’s prudent for dairy producers to take special precautions to ensure their continued good health.
Management strategies to help keep fresh cows healthy was the focus of the presentation by Dr. Gary Oetzel, DVM, during the second 2015 Cow College seminar at the Fox Valley Technical College’s regional learning center.
During his two-hour presentation, Dr. Oetzel, professor at the University of Wisconsin-Madison School of Veterinary Medicine, explored the common pitfalls in diagnosing and treating diseases in fresh cows. He also recommended logical treatment protocols using a variety of legal drugs.
His presentation also included information from his field research on ketosis and hypocalcemia.
Oetzel warned that tracking milk yield alone won’t provide quick detection of fresh cows that are sick.
“Doing that will put you a couple of days behind the curve,” he said, “and being a couple days behind that curve can be a really big loss.”
He emphasized the need to detect illness in cows before there’s a decline in milk yield.
“In early lactation, cows are primed to milk at the expense of themselves,” he said. “They will draw on body reserves to keep milk flowing even if they are not eating.”
The key to early detection of illness in fresh cow is following proper screening protocols, according to Oetzel. He said it’s easier to find sick cows in tie-stall barns, but it’s more of a challenge in larger groups of animals in freestall barns.
Oetzel noted that detecting sick cows can be done by observing their appetite.
“Synchronize the first milking with delivery of fresh TMR to the bunk,” he advised. “Timing of this must be extremely consistent, and there should be headlocks for all cows, with a space of 30 inches per cow.”
He recommended walking along in front of the cows after they’ve been locked up to fresh feed. “Evaluate the feed in front of each cow and evaluate feed intake compared to days in milk,” Oetzel said.
An important part of the screening process is evaluating the animals’ attitude and behavior. “Check the eyes, ears and stance of the cows, and compare those with expected behavior,” he suggested.
Another part of the process is walking behind the cows. “Look for vaginal discharge and manure consistency,” he recommended. “Rectal exams are optional, and vaginal exams should only be performed by vets.”
Oetzel stressed the need for having qualified and observant personnel working in fresh-cow pens. “Encourage development of subjective cow evaluation skills and humane treatment of sick and down cows.”
After identifying sick cows
Once a sick cow has been identified, Oetzel suggested performing a mini physical exam. “Observe the left flank because rumen can fill that,” he said. “Palpate the left flank if needed.”
Observing the animal’s left flank can provide clues to a possible displaced abomasum (DA).
“There may be a DA if the rumen is pushed away from the body wall, or if the last rib is sprung outward, and sometimes you can see the DA under the skin,” he said.
When checking an animal’s temperature, Oetzel noted that a fever is present when the rectal temperature is 103 degrees F or 1.5 degrees F above the group average during heat stress. “Not every cow needs to be checked every day, but by doing it, you may catch undetected fevers,” he said.
Oetzel recommended evaluating the cow’s respiratory rate, looking for increased expiratory effort and nasal discharge, and he recommends a ketosis check for any sick cow between two and 30 days in milk.
Specific fresh-cow diseases
People working with fresh cows should become good at picking up milk fever, he said.
“This is most likely to occur with a cow’s second or later lactation and from just before calving to 48 hours after,” he said. “Symptoms include cold ears, shuffling feet, rapid heart rate and muscle tremors.”
To begin treatment, he advised first tying the animal’s head to a hind leg, taking a pretreatment blood sample and then slowly administering 500 mL 23 percent IV solution of calcium gluconate over a period of 12-20 minutes. This should be done by monitoring the heart rate.
Because 25 to 40 percent of treated animals will have a hypocalcemic relapse within 12-18 hours, Oetzel recommended administering a second, slower calcium release treatment, either subcutaneously or orally once the cow is up and alert.
To diagnose toxic mastitis, the quarters and milk need to be examined. “Lift up the hind leg to get good access to all four quarters,” Oetzel said.
Symptoms include watery milk, severe dehydration and poor skin turgor. Treatment includes oral — NOT IV — calcium and 2 liters of hypertonic saline IV, followed by oral water intake, either drinking or pumping. A veterinarian should be called in severe or nonresponsive cases.
Pneumonia may be diagnosed if two of more of the these symptoms are present: coughing, increased respiratory effort, off-color nasal discharge and fever. Pneumonia may be treated with Excenel, Excede or Polyflex, according to label directions.
Ketosis may be present if there’s a sweet smell to the animal’s breath or by urine test strips, which must be read within 10 seconds after dipping.
Mild and moderate cases may be treated orally by propylene glycol or glycerol. Severe cases can be treated with dextrose IV, followed by an oral glucose precursor.
“Don’t treat all cows the same,” Oetzel advised. “We can manage high-risk cows by placing them in proper pens and by providing the correct amount of eating and resting space and by developing proper diagnostic and treatment protocols.”
Oetzel advised separating fresh cows in two or more groups. High-risk cows should be bedded on packs or sand-free stalls, and they should be milked less frequently (twice a day instead of three times).
He noted that reducing milking frequency is especially beneficial for lame cows. Citing a study of 500 lame cows from a 2,800-cow herd, he reported that 270 randomly assigned cows were milked three times per day and 230 were milked twice a day.
“The cows milked twice a day had no reduction in milk yield,” he said. “The reduction in milking frequency also lowered the probability for continued lameness and improved the animal’s body condition score.”
Oetzel stressed the need for herd managers to focus attention on early detection and treatment of sick cows.
“We are starting to do better of identifying high-risk fresh cows,” he said, “but consider creating multiple post-fresh pens when remodeling or expanding to make it easier to identify the high-risk animals.”
Source: Wisconsin State Farmer