The effect of exogenous progesterone on plasma LH and milk progesterone concentrations in multiple-suckling post-partum cows

Peters, A. R.; Hewitt, Denise; Lamming, G. E.

doi:10.1016/0378-4320(83)90014-3

Cited by 4 publications

(2 citation statements)

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“…Thus the effect may be inhibitory during the first 3 weeks (Williams et al, 1982 ;Azzazi et al, 1983) and stimulatory later Troxel and Kesler, 1984c). The further away from calving it is given, the more likely it is for progesterone to have a favourable effect on LH release and the amount of progesterone synthesized by the resulting corpus luteum (Peters et al, 1983). This inhibitory effect is brought about by a decrease in the amount of GnRH released, by a decrease of the self-regulating (or self-priming) effect of GnRH (Kesner et a/., 1982 ;Padmanabhan, 1982) or by oestradiol acting on the pituitary receptors of GnRH (Azzazi et al, 1983).…”

Section: Progesteronementioning

confidence: 99%

“…This effect acts on higher nervous centers since progesterone modifies neither the LH content nor the number of GnRH receptors in the pituitary (Moss et al, 19811. This sensitivity of the pituitary to negative feedback exercised by progesterone increases during the postpartum period (Peters et al, 1983). During the postpartum period, the amplitude and the duration of the LH peak induced by GnRH injection is higher in animals pretreated with progesterone Troxel and Kesler, 1984c).…”

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confidence: 99%

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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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