top of page

Part 7 | rbST: Friend or Foe?

Over the last few articles, several topics have been explored that explained rbST, why and how it is used and answered a few frequently asked questions. In the current climate of high input costs and the changes that occur, farmers need to seek out other ways to increase their profit margins. Using technology or biotechnology like rbST, can be the solution. Let's discuss whether rbST is a friend or a foe.


rbST helps farmers decrease their carbon footprint, increase the sustainability of the farm and help the environment. Supplementing six cows with rbST is equal to seven un-supplemented cows. Farmers can have smaller herds while maintaining the same milk yields. With fewer cows on the farm, farmers need less feed, water, electricity, land and have less manure production.


Although cows increase their feed intake when supplemented with rbST, comparing it to adding more cows, the feed consumption is less needing to feed an extra cow to produce the same amount of milk. The increased intake is about 300g/L on average and the extra nutrients maintain the higher milk production.


Previously, reproduction has had a negative connotation to rbST but has since been prover otherwise. Several studies have established that rbST can have a positive effect on reproduction and cows trated with rbST should be managed the same as genetically superior cows. A study by Starbuck et al. showed that even a single dose of rbST can improve the fertility of cows. Furthermore, Santos et al. showed that treatment with rbST can have positive effects on the cow's fertility. It's important to ensure that reproduction management and AI protocols are managed correctly.


Management on farms is crucial for a dairy to maintain high yields. With or without rbST, good management practices on the farm needs to be implemented for cows to produce at their highest yields. When using rbST, management on the farm is just as important as any other day and does not have to change, except for the injection of rbST every 14 days.


rbST does not influence the longevity of the cows. Studies have shown that cows supplemented with rbST produce more milk for a longer period after peak yield, but it does not affect the next lactation and thus cows can keep on producing. A study done by Huber et al. showed that cows treated over 4 consecutive lactations increased their milk yield and body weight gain, but it did not affect the production in the next lactation.


A safety assessment on rbST by Raymond et al., showed that somatic cell count and mastitis is affected by various factors like age, stage of lactation, season of the year and many more factors. Most mastitis cases happen early on in lactation around the first 2 months when rbST is not yet supplemented, thus rbST supplementation cannot influence the cow. The most important factor to consider when mastitis is involved is the husbandry practices that farms use. The better the practices, the less the mastitis cases are with or without using rbST.


Profitability is a very important factor to determine and to increase on a dairy farm. Supplementing dairy cows with rbST can help with increasing the profitability. By supplementing rbST when a cow reaches peak yield, we extend the peak yield for a longer period and thus increasing the liters of milk per cow per day over the entire lactation. When managed correctly and cows are allowed to increase their intake, the increase in liters could range from 5% to 25% of the lactation yield.

RbST has been in the industry for 30 years now and there has been a great deal of studies since it has been commercially approved. This is the time to really improve and try things like biotechnology to help the dairy industry grow and be sustainable.



  • Huber, J.T., Fontes, W.C., Sullivan, J.L., Hoffman, R.G., and Hartnell, G.F. 1997. Administration of recombinant Bovine Somatotropin to Dairy Cows for Four Consecutive Lactations. Journal of Dairy Science 80(10): 2355 – 2360.

  • Raymond, R., Bales, C.W., Bauman, D.E., Clemmons, D., Kleinman, R., Lanna, D., Nickerson, S., and Sejrsen, K. 2021. Recombinant Bovine Somatotropin (rbST): A Safety Assessment. Joint Annual Meeting of the American Dairy Science Association, Canadian Society of Animal Science and American Society of Animal Science. Montreal, Canada, 14 July 2009.

  • Santos, J.E.P., Juchem, S.O., Cerri, R.L.A., Galvão, Chebel, R.C., Thatcher, W.W., Dei, C.S., and Bilby, C.R., 2003. Effect of bST and Reproductive Management on Reproductive Performance of Holstein Dairy Cows. Journal of Dairy Science 87(4): 868-880.

  • Starbuck, M.J., Inkeep, E.K. and Dailey, R.A., 2005. Effect of a single growth hormone (rbST) treatment at breeding on conception rates and pregnancy retention in dairy and beef cattle. Animal Reproduction Science 93: 349-359.

26 views0 comments

Recent Posts

See All


bottom of page