Response of cyclic and post-partum suckled cows to injections of synthetic LH-RH

Webb, Robert I.; Ge, Lan; Haynes, N. B.; Hafs, H. D.; Manns, J. G.

doi:10.1530/jrf.0.0500203

Cited by 122 publications

(52 citation statements)

References 16 publications

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“…They diminish slowly during the final 3-4 weeks and rapidly 2-3 days before calving (Short, 1958 ;Randel and Erb, 1971 ;Smith et al, 1973 (Webb et al, 1977 ;Lishman et al, 1979 ;Kesler et al, 1980 ;Fonseca et al, 1980 ;Sheffel et al, 1980 ;Troxel et al, 1983) or after early weaning (Odde et al, 1980) or limited suckling with (Dunn et al, 1985) or without (Flood et al, 1979) GnRH injection. Many hypotheses have been put forward to explain this.…”

Section: Progesteronementioning

confidence: 99%

“…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).…”

mentioning

confidence: 99%

“…In dairy cows, the pulsatile release of LH and the sensitivity of the pituitary to hypothalamic GnRH appears 10 days after calving and is greater between 12 and 15 days after calving (Echterkamp and Hansel, 1973 ;Kesler et al, 1977Kesler et al, , 1979Peters et al, 1981 Suckling may have an effect at three levels. It reduces the frequency Walters et al, 1982a ;Edwards, 1985) and amplitude of LH release (Radford et al, 1978 ;Troxel et al, 1980 ;Webb et al, 1980, pituitary sensitivity to GnRH (Carruthers et al, 1978 ;Smith et al, 1981) and pulsatile release of GnRH by the hypothalamus Walters et al, 1982c ;Schallenberger and Peterson, 1982 (Schams et al, 1973 ;Kesler et al, 1977 ;Webb et al, 1977 ;Schallenberger et al, 1978 ;Smith et al, 1981 ;Walters et al, 1982c).At last, as well as a diminution in the interval between injection of oestradiol or GnRH and the LH peak, there is also an increase in the amplitude of this peak during the first 4 weeks after calving (Stevenson et al, 1983 ;Azzazi et al, 1983). 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.…”

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confidence: 99%

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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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Section: Progesteronementioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Endocrine regulation of postpartum ovarian activity in cattle : a review

Hanzen

1986

Reprod. Nutr. Dévelop.

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show abstract

“…These initial rises, probably resulting from luteinized follicles (Corah et al, 1974), may have an organising effect on the postpartum ovarian-pituitary-hypothalamic axis (Webb et al, 1977) and the reestablishment of regular oestrous cycles (Lamming et al, 1981;La Voie ef al, 1981 ). But as our data indicate, these initial peaks are not exclusive prerequisites for conception.…”

Section: Introductionmentioning

confidence: 99%