Radioimmunoassay for insulin-like growth factor-I in bovine milk

Zhao, Xiang; Groenewegen, P; McBride, B.W.; Burton, John H.; Elsasser, Theodore H.

doi:10.4141/cjas91-082

Cited by 12 publications

(10 citation statements)

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“…(Campbell and Baumrucker 1989). By day 56 postpartum, the concentration of milk IGF-I for combined parities was 4.5 * 0.5 nmol L-1 (Campbell and Baumrucker 1989 Zhao et al 1991). There are also parallels between the activity of IGF BP and IGF-I concentration in mammary secretions around the time of parturition (Vega et al 1991).…”

Section: Effects Of Growth Hormone On Body Conditionmentioning

confidence: 77%

“…In milk, interference by BP in acid-ethanol extracts may be attenuated as described by Campbell and Baumrucker (1989). However, given the results of Breier et al (1991b) and the knowledge that some back-binding of IGF-I to IGF BP occurs following neutralization of acid-ethanol extracts (Zhao et al 1991), more complete removal of the BP's is necessary for accurate immunoassay of milk IGF-I.…”

Section: Effects Of Growth Hormone On Body Conditionmentioning

confidence: 99%

See 1 more Smart Citation

A review of bovine growth hormone

Burton¹,

McBride²,

Block³

et al. 1994

Can. J. Anim. Sci.

132

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. 74: 16'7-201. Unprecedented numbers of technical papers, abstracts, and short communications have been published in the past decade regarding the effects of exogenous bovine growth hormone on milk production, health, and reproductive efficiency of treated dairy cows. In well-managed dairy herds, exogenous growth hormone increases milk production without altering normal variability in milk composition. This has held true regardless of dairy breed tested, geographical location studied, or feeding management system used. Also consistent across studies is the rapidity of the galactopoietic effect of administered bovine growth hormone, which arises from altered partitioning and use of post-absorptive nutrients and increased synthetic capacity of the mammary gland. Growth hormone and its associated peptide, insulin-like growth factor-I, are now known to provide chronic lipolytic, diabetogenic, and gluconeogenic signals to target tissues culminating in increased mammary gland availability of glucose and nonesterified fatty acids. Together with yet ill-defined effects on mammary secretory tissue, this homeorhetic control of metabolism elicited by exogenous growth hormone is so efficient that treated cows are not more susceptible to metabolic disorders than untreated cows. However, some studies have reported an increased frequency of mastitis in groups of treated cows. This has been attributed mainly to increased milk volume in the mammary glands of treated cows and no convincing data are available that show decreased mammary gland immunity as a result of growth hormone treatments. On the contrary, an expanding body of evidence implicates growth hormone as a key neuroendocrine factor that is required for immunological competence. Trends of decreased reproductive efficiency in cows treated with growth hormone have also been reported, but available data imply that this is probably an indirect effect via prolonged negative energy balance in cows treated in early lactation rather than a direct negative effect on estrous cycling via altered reproductive hormone profiles. The objectives of the present review are to bring into focus and summarize pertinent biological discoveries regarding the treatment of dairy cows with recombinant bovine growth hormone, and to explore areas where additional growth hormone research is needed or warranted.Key words: Growth hormone, somatotropin, dairy cows, insulin-like growth factor-I Burton, J. L., McBride, B. W., Block, E., Glimm, D. et Kennelly,E. 1994. L'horrnone de croissance bovinemais au point bibliographique. Can. J. Anim. Sci. 74: . D'innombrables m6moires techniques, r6sum6s analytiques et communications brdves ont 6t6 publi6s dans la dernidre d6cennie au sujet des effets de I'hormone de croissance bovine exogdne sur la production laitidre, sur la sant6 et sur les fonctions de reproduction des vaches laitidres trait6es. Dans les 6levages laitiers bien conduits, la GH exogbne accroit la production de lait sans modifier la variabilit6 normale de sa composition, et cela inddpendamme...

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Section: Effects Of Growth Hormone On Body Conditionmentioning

confidence: 77%

Section: Effects Of Growth Hormone On Body Conditionmentioning

confidence: 99%

A review of bovine growth hormone

Burton¹,

McBride²,

Block³

et al. 1994

Can. J. Anim. Sci.

132

View full text Add to dashboard Cite

show abstract

“…Tem-se verificado altas concentrações de IGF-I no colostro de bovinos, com níveis médios de 100 a 500 ng/mL, enquanto, no leite, são inferiores a 40 ng/mL no leite (Zhao et al, 1991;Vacher & Blum, 1993;Donovan et al, 1994;Hardon et al, 1997;. Nesta pesquisa, o objetivo da administração de rbST aos animais durante seu período seco foi de aumentar a concentração sérica de IGF-I e, conseqüentemente, as concentrações no colostro e subseqüentes secreções lácteas (Figura 3).…”

Section: Period Meanunclassified

IGF-I e IgG séricos e nas secreções lácteas em vacas tratadas com rbST no período pré-parto

et al. 2005

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RESUMO -Foram utilizadas 42 vacas holandesas gestantes e multíparas, distribuídas ao acaso em dois grupos, com o objetivo de se determinar possíveis alterações na concentração de IGF-I no colostro e nas secreções lácteas em resposta a mudanças na concentração sérica de IGF-I pré-parto, além de se avaliar comparativamente a flutuação sérica pré-parto de IGF-I em relação a IgG. O grupo tratado (n=21) recebeu 500 mg de somatotropina bovina recombinante (rbST) e o grupo controle (n=21) injeções de vitamina E. Os tratamentos foram iniciados 35 dias pré-parto e repetidos a cada 14 dias até o parto. Semanalmente, até o parto, avaliou-se o escore corporal (EC) e coletaram-se amostras de sangue da veia mamária. Foram amostrados o colostro e as secreções lácteas diariamente por sete dias pós-parto. O EC e a concentração sérica de ácidos graxos não-esterificados não diferiram entre os grupos. O grupo rbST apresentou maiores concentrações séricas de IGF-I na segunda e quarta semanas após o início dos tratamentos, não sendo encontradas diferenças entre os tratamentos ao parto. A concentração de IGF-I foi superior no colostro das vacas tratadas com rbST, não diferindo nas secreções subseqüentes. As concentrações séricas de IgG não diferiram entre tratamentos durante todo o período experimental, assim como as do colostro e demais secreções lácteas. As concentrações séricas de IGF-I e IgG variaram em função do período experimental, diferindo na amplitude e refletindo as grandes mudanças que ocorrem no último mês de gestação.Palavras-chave: colostro, fator de crescimento semelhante à insulina-I, imunoglobulinas, somatotropina IGF-I and IgG Serum Concentrations and in Mammary Secretions in Cows Treated with rbST PrepartumABSTRACT -Forty-two Holstein cows, pregnants and multiparous, wereassigned randomly to two groups to determine the possible alterations of IGF-I concentration in colostro and mammary secretions by changes in pre-partum blood serum IGF-I concentration, and also to compare its temporal changes with the serum immunoglobulin G (IgG) in pre-partum period. The treated group (n=21) received 500 mg of recombinant bovine somatotropin (rbST), and the control group (n=21) vitamin E injections. The treatments had been initiated 35 days prepartum and repeated each 14 days until partum. Weekly it was evaluated body condition scores and was collected blood by mammary venepuncture until partum. Colostrum and mammary secretions were collected daily for seven days pos-partum. Body condition scores and nonesterified fatty acid concentration did not differ between the groups. To the rbST group IGF-I concentration was superior on second and fourth weeks after the treatment had been initiated. However, no treatment differences were found at partum. Concentration of IGF-I was superior in colostrum of cows treated with rbST, but it did not differ in subsequent mammary secretions. IgG serum concentration did not differ between treatments during the experimental period, neither in colostrum and subsequent mammary secretions. IGF-I and IgG...

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“…With regard to the assay performances, the absolute LOD of the assay was 0.025 ng mL À1 of IGF-1 and the LOQ was 0.082 ng mL À1 (0.1 and 0.32 ng mL À1 of milk, respectively), which was around the average of some of those reported in the literature or extrapolated from the experimental procedure, and ranging from about 0.1 to 1 ng mL À1 for RIA coupled with extractive methods (Collier et al, 1991;Corps et al, 1988;Malven et al, 1987;Prosser, Fleet, & Corps, 1989;Vega, Gibson, Skaar, Hadsell, & Baumrucker, 1991;Zhao, Groenewegen, McBride, Burton, & Elsasser, 1991), or with purification by acidic chromatography (Donovan et al, 1991(Donovan et al, , 1994Eriksson, Duc, Froesch, & Zapf, 1993). Furthermore, the nonextractive method involving the use of IGF-2 as blocking agent, proposed by Daxenberger et al (1998), had a determination limit of about 1 ng of analyte per mL of milk, which is still sufficient to measure the "naturally occurring IGF-levels in milk".…”

Section: Assay Performancementioning

confidence: 98%