LH Release in Response to GnRH during the Postpartum Period of Dairy Cows

Fernandes, L C; Thatcher, W.W.; Wilcox, C.J.; Call, Edward P.

doi:10.2527/jas1978.462443x

Cited by 103 publications

(49 citation statements)

References 13 publications

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“…Plasma FSH concentrations rise within 5 days after parturition with little subsequent change up to Day 30 (Lamming, Wathes & Peters, 1981). Pituitary responsiveness, in terms of LH release, to single injec¬ tions of 100-500 µg GnRH increases during the first 10 days post partum (Fernandes, Thatcher, Wilcox & Call, 1978;Foster, Lamming & Peters, 1980) whilst responsiveness of the FSH gonadotrophs shows a tendency to decrease (Foster et al, 1980). However, these studies describe responses to pharmacological doses of GnRH and may not repre-sent physiologically relevant changes.…”

Section: Introductionmentioning

confidence: 75%

Hormone responses to exogenous GnRH pulses in post-partum dairy cows

Peters¹,

Pimentel²,

Ge³

1985

Reproduction

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Section: Introductionmentioning

confidence: 75%

Hormone responses to exogenous GnRH pulses in post-partum dairy cows

Peters¹,

Pimentel²,

Ge³

1985

Reproduction

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“…After calving, pituitary LH content (Labhsetwar, Collins, Tyler & Casida, 1964;Saiduddin, Riesen, Tyler & Casida, 1968;Cermak, Braden, Manns, Niswender & Nett, 1983), GnRH-induced release of LH (Kesler, Garverick, Youngquist, Elmore & Bierschwal, 1977;Webb, Lamming, Haynes, Hafs & Manns, 1977;Fernandes, Thatcher, Wilcox & Call, 1978) and mean concentrations of LH in serum (Peters, Lamming & Fisher, 1981;Williams et al, 1982) were lower than those observed just before the first post-partum oestrus. Similar changes in these indices ofLH secretion occur in sheep (Jenkin, Heap & Symons, 1977).…”

Section: Introductionmentioning

confidence: 99%

Relationship between pituitary GnRH-binding sites and pituitary release of gonadotrophins in post-partum beef cows

et al. 1986

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“…The magnitude of the GnRH-induced release of LH was directly proportionnal to follicular diameter (Smith et al, 1983 ;Lishman et al, 1979) and oestrogen concentrations in postpartum cattle (Fernandes et al, 1978 Manns et al, 1983) but tend to increase during the first few days after calving (Webb et al, 1980 ; Peters et al, 19811. ).…”

mentioning

confidence: 99%

Endocrine regulation of postpartum ovarian activity in cattle : a review

Hanzen

1986

Reprod. Nutr. Dévelop.

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Summary. The Clinically, the postpartum period is characterized by a period of behavioural anoestrus, the duration of which differs in different breeds.If the detection of oestrus is optimal, anoestrus lasts for 20 to 70 days in dairy cows Callahan et al., 1971 ;Schams et al., 1978 ;Pirchner et al., 1983 ;Richardson et al., 1983 ;Etherington et al., 1984). This period is highly variable in suckled cows and lasts from 30 to 110 days (Wiltbank and Cook 1958 ;Oxenreider 1968 ;Graves et al., 1968 ;Casida et al., 1968 ; Nancarrow et al., 1977 ;Holness et al., 1978 ;Wettemann et a/., 1978 ;Short et al., 1979 ;Dunn and Kaltenbach, 1980 ;Kesler et al., 1980 ;Randel, 1981 ;Montgomery, 1982 ;Peters and Riley, 1982 . Jainudeen et al., 1982Bastidas et al., 1984 ;King and Mc Leod, 1983Leod, /1984Hansen and Hauser, 1984 ;Montgomery et al., 1985).Assay of progesterone in plasma or milk has shown that 88 % of animals of dairy breeds have an luteal activity present by 35 days after calving (Ball and Lamming, 1983) and 95 % within 50 days (Bulman and Lamming, 1978). According to different authors, the first rise of progesterone appears between 16 and 69 days after calving in dairy cows (Webb et al., 1977(Webb et al., , 1980Pirchner et al., 1983) and between 56 and 96 days in suckled cows (Fonseca et al., 1980 ;Peters and Riley 1982 ; Jainudeen et al., 1982 Jainudeen et al., /1983Montgomery et al., 1985).It is possible to detect ovarian follicles by rectal palpation in both milked and suckled cow from the second week after calving (Saiduddin et al., 1968 ;Callahan et al., 1971 ;Kesler et al., 1979 ;Webb et al., 1980 ;Kesler et al., 1980 ;Stevenson et al., 1983 (Wiltbank et al., 1962(Wiltbank et al., , 1964Dunn et al., 1969 ; Lammond, 1970 ;Corah et al., 1975 ;Whitman et a/., 1975 ;Duffour, 1975 ;Holness et al., 1978 ;Carstairs et al., 1980 ;Dunn and Kaltenbach, 1980 ; Gauthier and Thimonnier, 1982 ;Peters and Riley, 1982 ; Mc Leod, 1983/1984 ;Rutter and Randel, 1984). Some authors have found that overfeeding improves ovarian (Wiltbank et al., 1962(Wiltbank et al., , 1964Hansen et al., 1982) or pituitary (Beal et al., 1978 ;Jordan and Swanson, 1979 ;Lishman et al., 1979 ;Moss et al., 1982) function. Others have found no relation between feeding and the ovarian (Lishman et al., 1979 ;Carstairs et al., 1980) or pituitary (Hill et a/., 1970 ;Dunn et al., 1974 ;Spitzer et al., 1978 ;Haresign, 1981 ;Rutter and Randel, 1984) activity.Little is known about the mechanism under which diet exerts its effect. It is conceivable that feeding influences the ovarian response to gonadotropins (Gombe and Hansel, 1973). There was a positive correlation between the degree of fatness of an animal and the plasma concentration of 17 !3-oestradiol, 7 weeks after calving (Lishman et al., 1979).Feeding affects the release of luteinizing hormone (LHI and subsequent luteal function Spitzer et al., 1975 ;Apgar et al., 1975 ;Beal et al., 1978). It has been observed that the release of LH induced by gonadotropin releasing hormone (GnRH) injection was grea...

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LH Release in Response to GnRH during the Postpartum Period of Dairy Cows

Cited by 103 publications

References 13 publications

Hormone responses to exogenous GnRH pulses in post-partum dairy cows

Hormone responses to exogenous GnRH pulses in post-partum dairy cows

Relationship between pituitary GnRH-binding sites and pituitary release of gonadotrophins in post-partum beef cows

Endocrine regulation of postpartum ovarian activity in cattle : a review

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