Effect of administration of recombinant bovine somatotropin on health and performance of lactating dairy cows diagnosed with hyperketonemia.
The effect of administering recombinant bovine somatotropin (rbST) to cows with hyperketonemia during the early postpartum period on health, metabolic parameters, milk production, and early reproductive performance was evaluated in a double-blinded clinical trial. Cows from 8 dairy herds in New York State were tested weekly between 3 and 16d in milk for elevated serum β-hydroxybutyrate. Cows were enrolled in the study when blood β-hydroxybutyrate was ≥1.3mmol/L for the first time. Enrolled cows were randomly assigned to a treatment (n=273) or placebo control (n=270) group. Treated cows were given 325mg of rbST subcutaneously on the day of enrollment and again 14d later. Control cows received the same regimen except the syringe contained only the carrier without somatotropin. After enrollment, blood samples were collected weekly for 4wk and submitted to the laboratory to be analyzed for selected metabolites. Risk ratios for clinical diseases subsequent to treatment were calculated using Poisson regression. Continuous data were analyzed using linear mixed models. Time to first insemination was assessed with survival analysis. In the 42d following the first administration of rbST, incidence risks of displaced abomasum, clinical ketosis, metritis, clinical mastitis, and lameness were not different between treatment groups. Cows treated with rbST had a slightly lower body condition score 28d after enrollment compared with control cows. In the 4wk following enrollment, serum nonesterified fatty acids and aspartate amino-transferase were slightly higher for treated than control cows, respectively. Serum glucose, calcium, haptoglobin, and β-hydroxybutyrate were similar between groups. Treatment had no effect on resolution of hyperketonemia in any of the 4wk after enrollment. Milk production in either of the 2-wk periods after each treatment was not different between treated and control cows. Furthermore, milk production was not different between groups from enrollment to 98d in milk (42.6±0.6 and 42.1±0.7kg/d for treatment and control groups, respectively). Treatment had no effect on time to first insemination (83 and 74d in milk for treatment and control groups, respectively; hazard ratio=0.72) or first insemination pregnancy risk (27 and 29% for treatment and control groups, respectively; risk ratio=0.92). Based on the current results, it is not recommended to use a low dose of rbST as therapy for cows with hyperketonemia.
Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
K
K
Gohary
Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
K E
KE
Leslie
Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
J
J
Ford
Perry Veterinary Clinic, Perry, NY 14530.
M
M
Capel
Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
S J
SJ
LeBlanc
Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, N1G 2W1, Canada. Electronic address: tduffiel@uoguelph.ca.
T F
TF
Duffield
D020155:3-Hydroxybutyric Acid / Q000097:blood; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D013006:Growth Hormone / Q000627:therapeutic use*; D006242:Haptoglobins / Q000737:chemistry; D007662:Ketosis / Q000662:veterinary*; D007774:Lactation / Q000187:drug effects; D008892:Milk / Q000737:chemistry; D011247:Pregnancy
D005230:Fatty Acids, Nonesterified; D006242:Haptoglobins; C073294:growth hormone, bovine; D013006:Growth Hormone; D020155:3-Hydroxybutyric Acid
dairy cow; hyperketonemia; ketosis treatment; recombinant bovine somatotropin