Growth Hormones

1
Growth Hormones

• Common Hormones.
• What they are.
• What they do.
• Scientific Studies.

2
Most Commonly Used Growth Hormone

• BST (Bovine Somatotropin)
• Also known as
• POSILAC
• BGH
• rBGH
• rBST

3
What is BST?

• Bovine Somatotropin is a genetically engineered
  copy of a naturally occurring hormone produced by
  cows.
• In contrast to steroids, BST is a protein
  hormone. (Protein hormones are not biologically
  active if ingested orally)
• BST has been in use since February 1994 and was
  approved by the FDA in November of 1993.

4
What does BST do?

• BST allows for higher milk production in dairy
  cows thus keeping the number of cows in the herd
  to a minimum.
• Has direct and indirect effects in coordinating
  the metabolism of various body organs and tissues
  to the requirements of milk production, In
  particular by promoting production of the hormone
  IGF-1, which stimulates glands in the cow's
  udder.
• Small quantities of BST are found in all cows'
  milk. More recently, high-yielding dairy cows
  were found to have higher circulating levels of
  naturally occurring BST, and it was discovered
  that the injection of BST could increase the milk
  yield of cows by minimizing the rate of yield
  decline after peak lactation

5
Scientific Studies

• Effects of Sustained Release Bovine Somatotropin
  on Animal Health in Commercial Dairy Herds. R.J.
  Collier.
• Objective Determine the health of dairy cows
  given bovine somatotropin(bST) for one lactation
  was evaluated in 28 commercial herds located in
  four regions of the United States.

6
Results

• Average 305-d test-day milk yields were 932 kg
  greater for bST treated cows.
• Pregnancy rates, days open, twinning, cystic
  ovaries, or abortions were unaffected by
  treatments.
• Supplementation of cows with bST had no effect on
  total mastitis cases, total days of mastitis,
  duration of mastitis, or the odds ratio of a cow
  to develop mastitis.
• Supplemented cows had a slight increase in foot
  disorders.
• Overall, the results confirm that label
  directions for bST are adequate for safe use
  under field conditions. All clinical signs
  observed in this study occur normally in dairy
  herds and were managed in cows supplemented with
  bST.

7
Scientific Studies

• Effect of bST and Reproductive Management on
  Reproductive Performance of Holstein Dairy Cows.
  J. E. P. Santos.
• Objective To determine the effects of bovine
  somatotropin (bST) and two artificial
  insemination (AI) protocols on reproductive
  performance of Holstein cows.

8
Results

• bST improved conception rates in cyclic cows.
• Treatment with bST tended to reduce pregnancy
  loss in all cows and improved pregnancy
  maintenance in cyclic dairy cows.
• However, bST tended to reduce the rate of
  detected estrus (periodic state in which the
  female is most receptive to mating) in cattle.

9
Scientific Studies

• Effect of Recombinant Bovine Somatotropin on Milk
  Production and Composition of Cows with
  Streptococcus uberis Mastitis. D. Hoeben.
• Objective The protective effect of bovine
  somatotropin (bST) during experimental
  Streptococcus uberis mastitis in cows was studied.

10
Results

• In the treated cows, total milk production
  significantly increased after the first and
  second bST treatments.
• After infection, milk production decreased 24 and
  40 in the infected quarters, 6 and 14 in the
  uninfected quarters, and 15 and 28 overall for
  treated and control cows.
• In the bST group, milk production was completely
  restored after 3 wk, but, in the control group,
  total production and the production of the
  infected quarters remained lower than
  pre-infection production.
• The amount of bacteria in milk was higher in the
  control cows.
• Somatotropin protected the mammary gland from
  excessive production losses and compositional
  changes during a subsequent episode of
  experimentally induced Streptococcus uberis
  mastitis and significantly improved the
  normalization of production and composition.

11
Conclusion

• Not much Proven opposition.
• Still are many arguments against it.
• IGF-1
• Mastitis
• Risk characterization has pointed to an
  association between circulating IGF-1 levels and
  an increased relative risk of breast and prostate
  cancer. In addition, the possible contribution of
  life span exposure towards dietary IGF-1 and
  related proteins, present in milk from rbST
  treated cows, to gut pathophysiology particularly
  of infants, and to gut associated cancers need to
  be evaluated.
• FDA
• The FDA and other scientific and regulatory
  bodies have thoroughly examined the safety of
  milk produced by rbST-treated cows and have
  concluded that it is safe. The consumption of
  dietary IGF-1 plays no role in either inducing or
  promoting any human disease, nor does it cause
  malignant transformations of normal human breast
  cells .........the suggestion that IGF-1 in milk
  can induce or promote breast cancer in humans is
  scientifically unfounded and misguided. FDA has
  determined that milk from rbST-treated cows is
  safe for human consumption and has not been found
  to be different from milk from non-treated cows."

12
References

• http//lscgw.monsanto.com/DairyOC/docnew.nsf/id/FB
  4C4B8B1E44892286256EC3005850E7/file/Effect20of2
  0bST20and20Reproductive---Santos.pdf
• .http//lscgw.monsanto.com/DairyOC/docnew.nsf/id/F
  B4C4B8B1E44892286256EC3005850E7/file/Use20of20B
  ovine20Somatotropin20--20Moreira.pdf
• .http//lscgw.monsanto.com/dairyoc/docnew.nsf/id/F
  0093EA9DD2E706A86256C1500687900/file/CollierPAMP.
  pdf
• http//lscgw.monsanto.com/dairyoc/docnew.nsf/id/93
  4A8C0E5317895286256BF9006B2C8C/file/abstract1.pdf
  
• http//lscgw.monsanto.com/dairyoc/docnew.nsf/id/52
  DDEC85D06D025686256C550061A2C6/file/IFST20on20B
  ovine20somatotropin.pdf
• Darin L. Henry, DVM