By: Gennadii Bondarenko, Ph.D.
Ruminant Nutritionist
Grand Valley Fortifiers
To prove Effecacy of ASA boluses, a series of mini trials on five high producing dairy herds in Southwestern Ontario (3 robot and 2 parlor) was conducted. The farmers were provided ASA boluses with concentration of 15.5 g of ASA per bolus and starting from mid April 2024, the farmers randomly selected every other mature cow and every other heifer for treatment. Mature cows obtained the first treatment (8 boluses) within 12 hours of calving and the second treatment (8 boluses) 24 hours after the first application. Pregnant heifers received one treatment (8 boluses) approximately 14 days before expected calving date. The farmers recorded all health events and production information for treated (AS group) and untreated animals (control group). Udder health control was done either by measuring somatic cell count in milk (on four farms) or electrical conductivity (on one robot farm). Altogether, 203 cows participated in the trial – 99 cows in ASA group and 104 cows in control group. Productivity data was analyzed as average daily milk yield, fat percentage and protein percentage within the first 90 days after calving. Milk yield was adjusted to fat and protein content (4% butterfat and 3.3% true protein), using the methodology of International Dairy Federation (2015).
Table 1 summarizes the average for all farms. Numerical differences were observed in a variety of areas though on average ketotis was the largest health incidence improved with treatment. There was a 10% reduction of SCC in ASA group. Although the average productivity was very high in both groups (about 50 kg of FPCM within the first 3 months after calving), the animals treated with ASA in transition period still had 1.3 kg higher milk as compared to control.

Table 2 evaluates mature cows. Three farms demonstrated positive response in milk production and milk response varied from +1.1 kg (Farm C), to +3.6 kg (Farm B) and even +5.0 kg (Farm A). Farm D showed no difference in milk, and Farm E demonstrated negative response (-1.8 kg). Overcrowding in close-up and fresh cow pens was occurring at Farm E, the added stress could potentially impact Effecacy of ASA boluses application. As to the udder health parameters, four farms demonstrated reduction of SCC in ASA group and response varied from just 2600 to almost 99000 SCC. The robot farm B, which used milk conductivity as udder health control, showed very slight increase in milk conductivity in ASA group (+1.3 conductivity units).


The large-scale trials, conducted by Penn State University, demonstrated +1.45 kg of energy-corrected milk yield increase in ASA treated multiparous cows within first 60 days in milk, and +5 kg of milk yield improvement in ASA treated heifers (Barragan et al., 2020, 2021).
Based on GVF numbers, a larger response was seen in mature cows and a lower response in heifers. The low response in heifers may be explained by difficulties applying ASA boluses 2 weeks before calving or the fact that many were sold the summer of the trial thanks to high prices such that they left the herd before final measurements could be taken.
Overall, GVF trials show that application of ASA boluses in transition period could be considered a viable strategy to reduce systemic inflammation. With reduced inflammation comes improved productivity and reduced SCC after calving.
If you are interested in learning more about this study and potentially utilizing ASA boluses in your operation, contact your GVF Nutrition Consultant or visit: farmersdepot.ca/asa-bolus for product details.
References:
A. Barragan, E. Hovingh, S. Bas,J. Lakritz, L. Byler, A. Ludwikowski, S. Takitch, J. Zug, and S. Hann. Effects of postpartum acetylsalicylic acid on metabolicstatus, health, and production in lactating dairy cattle. J. Dairy Sci. 2020, 103:8443–8452 https://doi.org/10.3168/jds.2019-17966
A. A. Barragan, S. Bas, E. Hovingh, and L. Byler. Effects of postpartum acetylsalicylic acid on uterine diseases and reproductive performance in dairy cattle. JDS Communications 2021; 2. https://doi. org/10.3168/jdsc.2020-0047
International Dairy Federation. (2015). A common carbon footprint approach for the dairy sector. The IDF guide to standard life cycle assessment methodology. (Bulletin of the IDF n° 479/2015).
This article was written for the Winter 2024 Dairy Grist. To read the whole Dairy Grist, click the button below.