The 42nd annual conference of the American Association of Bovine Practitioners was held in September. During the program, more than 45 research summaries were presented. These are 15-minute presentations that summarize some of the current cattle research. Here are five with relevant take-home messages.
1. The effect of plane of nutrition on calf scours
In this Cornell University study, calves were fed either a conventional milk replacer (20/20 at 1 pound of dry matter per day) or a high plane of nutrition (28/20, fed to metabolic body weight; approximately 2.5 pounds of DM per day) to provide extra energy. Following experimental infection with Cryptosporidium (crypto), calves fed the high-plane diet maintained better hydration, overcame diarrhea faster, grew better and had a higher feed-conversion rate than the calves fed the conventional diet.
Take-home point: Providing dairy calves with a higher level of nutrition significantly reduced the effect of scours and should be considered as a feeding option.
2. The association of digital cushion thickness and lameness
In this study at Cornell University, authors measured body condition scores, lameness scores and the thickness of the digital cushion in the hoof with ultrasound in more than 500 lactating cows. As you might expect, cows with a lower BCS had a thinner digital cushion in their hoof. These cows also had a significantly greater prevalence of sole ulcers and white-line disease, likely due to the decreased cushion effect of the fat pad.
Take-home point: While diet may also have an effect on non-infectious lameness, hoof anatomy, specifically the amount of fat cushioning bone from the hoof, also has a strong association with sole ulcers and white-line disease.
3. Level of milk production and reproductive performance
In this study conducted at the University of Guelph, Dairy Herd Improvement records from 6,326 Canadian herds were used to examine the association between milk production and reproductive performance on the individual and herd level. At the herd level, each 2,204-pound increase in herd mature equivalent milk was associated with a 0.7 percent increase in pregnancy rate. For individual animals, cows in the highest level of production were 5 percent more likely to be pregnant than cows in the lowest level.
Take-home point: High levels of milk production and reproductive performance are compatible.
4. On-farm culture as a basis for mastitis treatment decisions
The University of Wisconsin authors analyzed the effect of on-farm milk culture to guide treatment decisions for a variety of parameters. Findings showed the use of on-farm culture resulted in less re-treatments, no differences in days to cure, a reduction in days out of the tank, no differences in the recurrence of mastitis, somatic cell count, milk yield and herd removal post-enrollment.
Take-home point: The use of on-farm milk culturing for mastitis treatment decisions is a worthwhile procedure.
5. The effect of negative energy balance
The Cornell University authors measured blood non-esterified fatty acids (NEFA) and beta hydroxybutyrate (BHBA or ketones) in 876 pre-calving and 826 post-calving cows in 62 herds for negative energy balance. Results indicate that negative energy balance was associated with an increase in clinical ketosis and displaced abomasum, decreased milk production (not heifers) and decreased pregnancy rate. Forty-two percent of herds in the study had more than 15 percent of cows with an elevated BHBA.
Take-home point: Prevalence data indicate that many herds have an opportunity to improve energy status in their transition cows.
It is important to be aware of the results from published trials like these in order to make sound veterinary decisions with herd economics in mind. Clinical impressions can be useful in some situations where there is limited research, but use caution to not over-interpret these impressions. Also be careful about inferring an outcome that was not specifically noted in the trial. Use this context when evaluating new programs or protocols with your veterinarian.
Mark J. Thomas is a veterinarian and partner in Countryside Veterinary Clinic LLP in Lowville, N.Y.