Somatomedin C and other hormones in dairy cows around parturition, in newborn calves and in milk

Ronge, H.; Blum, J. W.

doi:10.1111/j.1439-0396.1988.tb00190.x

Cited by 79 publications

(66 citation statements)

References 22 publications

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“…As concentrações médias de AGNE em todos os períodos e no parto, independentemente do tratamento, foram superiores à encontrada por Ronge & Blum (1988), que observaram concentração média de 331 mmol/L de AGNE em vacas durante o período pré-parto. Putnam et al (1999), suplementando vacas com rbST durante seu período seco a partir de 28 dias pré-parto, encontraram valores de AGNE semelhantes aos obtidos neste estudo, com níveis médios de 600 mmol/L na semana que antecedeu o parto.…”

Section: Resultsunclassified

“…Até a terceira semana, os animais desse grupo não apresentaram diferenças nas concentrações séricas de IGF-I, observando-se queda a partir da quarta semana. Ronge & Blum (1988) …”

Section: Resultsunclassified

“…Essa menor amplitude de variação encontrada nos animais do grupo rbST está relacionada ao fato de não se ter observado diferenças entre os níveis de PT a partir da quarta semana de tratamento até o parto, enquanto os animais do grupo controle apresentaram diferenças significativas no mesmo período. Ronge & Blum (1988) também verificaram redução da concentração da variável próximo à data de parição, embora com média inferior à encontrada neste estudo, que foi de 6,67 g/100 mL.…”

Section: Period Meanunclassified

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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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Section: Resultsunclassified

“…Até a terceira semana, os animais desse grupo não apresentaram diferenças nas concentrações séricas de IGF-I, observando-se queda a partir da quarta semana. Ronge & Blum (1988) …”

Section: Resultsunclassified

Section: Period Meanunclassified

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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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“…In these animals, the rise in GH concentration peaks when the forelegs of the calf are visible in the uterus (Reynaert et al 1976). After the expulsion of the calf, the GH levels may remain elevated for 1-2 days (Ronge & Blum 1988). Reynaert et al (1976), in constrast, suggest that GH levels are restored to preparturient levels immediately after parturition in heifers.…”

Section: Parturitionmentioning

confidence: 97%

GH as a co-gonadotropin: the relevance of correlative changes in GH secretion and reproductive state

Hull

Harvey

2002

Journal of Endocrinology

104

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It is now well established that exogenous GH promotes sexual maturation and reproductive function. The possibility that this may reflect physiological actions of endogenous GH has, however, rarely been considered. Correlative changes in GH secretion and reproductive state (puberty, pregnancy, lactation, menopause and ovarian cycles) are thus the primary focus of this review. GH secretion is, for instance, elevated during major transitions in reproductive status such as puberty and pregnancy. In some cases, augmented circulating GH levels are paired with hepatic GH resistance. This interaction may permit selective activation of gonadal responses to GH without activating IGF-I-mediated systemic responses. This selective activation may also be mediated by autocrine, paracrine or intracrine GH actions, since GH is also synthesized in reproductive tissues. Correlative changes in GH secretion and reproductive state may be mediated by events at the hypothalamic, pituitary and gonadal level. In addition to direct effects on gonadal function, GH may influence reproductive activity by increasing gonadotropin secretion at the hypothalamic and pituitary level and by enhancing gonadotropin responsiveness at the gonadal level. The close association between reproductive status and the somatotrophic axis supports the physiological importance of GH in reproductive function.

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“…Most liver-produced IGF-I is bound by the GHdependent BP at or near the time of secretion but the BP status of IGF-I acting in an autocrine or paracrine fashion is not well-defined and may be tissue-specific. The IGF BP may be elevated in blood of growing cattle (Ronge and Blum 1988) which also have greater blood concentrations of GH, IGF-I, and insulin than older animals . Con-sidering the complexity of normal regulation of mammary cell physiology (Akers 1985;Imagawa et al 1990), it is probable that GH does not act alone during galactopoiesis.…”

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

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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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Somatomedin C and other hormones in dairy cows around parturition, in newborn calves and in milk

Cited by 79 publications

References 22 publications

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

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

GH as a co-gonadotropin: the relevance of correlative changes in GH secretion and reproductive state

A review of bovine growth hormone

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