Regulation of Luteinizing Hormone Secretion in Prepubertal Heifers Fed an Energy-Deficient Diet1

Kurz, Scott G.; Dyer, R. M.; Hu, Yao; Wright, Micah; Day, M. L.

doi:10.1095/biolreprod43.3.450

Cited by 26 publications

(13 citation statements)

References 20 publications

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“…Error bars represent 95% confidence limits for each mean. (Reproduced with permission from Kurz et al, 1990. ) There is a prolonged response to inhibition by oestradiol on release of LH pulses in heifers (Kurz et al, 1990; Fig.…”

Section: Growth-nutritionalintakementioning

confidence: 99%

See 1 more Smart Citation

Endocrine basis for puberty in heifers and ewes

Kinder

Bergfeld²,

Wehrman³

et al. 2019

Proc

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Maturation processes that culminate in puberty and sexual maturity are initiated before birth, continue through prepuberty ( > 50 days before puberty) and peripuberty (50 days before puberty) and are completed early after puberty. The hypothalamus is the primary site of change during transition to sexual maturity. Maturation of the hypothalamus results from decreased negative feedback of oestradiol that leads to increased frequency of release of LH pulses. Increased tonic release of LH pulses during sexual maturation is the primary endocrine factor that regulates the onset of puberty in ewe lambs and heifers. Increased frequency of release of LH pulses enhances development of ovarian follicles which produce enough oestradiol to induce behavioural oestrus and a preovulatory surge of gonadotrophins.In later stages of peripuberty, ovulation or luteinization of follicles results in transient increases in progesterone for shorter periods than is typical for luteal phases of the oestrous cycle of mature ewes and cows. Transient increases in progesterone are not generally preceded by behavioural oestrus. After the demise of the transient luteal structures, puberty is attained with occurrence of the first behavioural oestrus that is accompanied by ovulation and development of a corpus luteum with a typical lifespan. At puberty, all components of the hypothalamicpituitary-ovarian axis are in place for oestrous cycles to be expressed. Factors that can influence the pubertal rise in release of LH pulses are genotype, gender, season of year when pubertal age is attained, growth or nutritional intake, social cues or treatment with exogenous progestins. Sexual maturation continues after puberty with an enhanced probability of pregnancy occurring from actions of ovarian steroids at the uterus. Prepubertal Reproductive SystemThe final component of the reproductive endocrine system to develop that regulates time of onset of puberty in heifers and ewes is the hypothalamus (Schams et al., 1981;Foster et al., 1986;Kinder et al.,

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Section: Growth-nutritionalintakementioning

confidence: 99%

“…(Reproduced with permission from Kurz et al, 1990. ) There is a prolonged response to inhibition by oestradiol on release of LH pulses in heifers (Kurz et al, 1990; Fig. 6) and ewe lambs (Foster et al, 1986), if the amount of dietary energy is limiting during prepuberty.…”

Section: Growth-nutritionalintakementioning

confidence: 99%

Endocrine basis for puberty in heifers and ewes

Kinder

Bergfeld²,

Wehrman³

et al. 2019

Proc

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“…The critical event leading to the onset of puberty in ruminants seems to be a prepubertal increase in frequency of LH pulses (Foster et al, 1975;Day et al, 1984;Kinder et al, 1987). Severe restriction of dietary energy suppresses pulsatile release of LH and prevents or delays onset of puberty (Foster et al, 1989;Kurz et al, 1990). Based on these observations, it has been hypothesized that differences in age a t puberty associated with differences in growth rates are attributed to effects on timing of the prepubertal increase in pulsatile LH secretion.…”

Section: Reproductive Traitsmentioning

confidence: 99%

Effects of recombinant bovine somatotropin and dietary energy intake on growth, secretion of luteinizing hormone, follicular development, and onset of puberty in beef heifers2

Hall

Schillo

Fitzgerald

et al. 1994

Journal of Animal Science

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The effects of dietary energy and recombinant bovine somatotropin (bST) on pattern of LH release, follicular development, and onset of puberty were studied in 40 Angus heifers. At 7 mo of age, heifers were assigned to a 2 x 2 factorial experiment; the main effects were dietary energy (high [HDE]: 14.15 Mcal of ME/d or moderate [MDE]: 10.84 Mcal of ME/d) and somatotropin (bST; 350 mg every 2 wk or vehicle). Beginning at 9 mo of age, heifers were observed twice daily for estrous activity. From 10.5 to 12 mo of age, five heifers from each treatment group were selected for weekly ultrasound examination of ovarian structures and biweekly sequential blood sampling to determine concentrations of LH. Somatotropin treatment altered intermediary metabolism in a manner consistent with enhanced accretion of lean tissue and decreased deposition of fat. The HDE heifers were younger (P < .001) at puberty than the MDE heifers, but BW at puberty was not different among treatment groups. Age and body weight at puberty were not affected by bST. Frequency of LH pulses increased within the 10.5 to 12 mo of age sampling window in HDE-treated heifers but not in MDE heifers (dietary energy x month of age; P < .02). Secretion of LH was unaffected by bST. Ovaries of bST-treated heifers tended (P < .09) to have fewer follicles > 5 mm in diameter than those of vehicle-treated heifers. We conclude that chronic treatment with bST did not alter age at puberty or pattern of LH release in heifers and that even modest differences in energy intake influence the timing of the prepubertal increase in pulsatile LH release.

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“…According to Schillo et al (1992), prepubertal increase in pulsatile LH secretion could be the rate-limiting step in sexual maturation. Dietary restriction can prevent the prepubertal increase in LH pulse frequency, delaying puberty onset (Kurtz et al, 1990;Schillo et al, 1992;Steiner et al, 1983). On the other hand, increasing energy intake can increase LH pulse frequency (Kurtz et al, 1990).…”

Section: Nutrition and Neuroendocrine Controlmentioning

confidence: 99%

004 Recommended Duration for Evaluating Feed Intake and Validating the Residual Feed Intake Model in Brangus Heifers

Kriese-Anderson

Mahler

Brandebourg

et al. 2016

Journal of Animal Science

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In order to determine optimal measurement days, variables best describing variation for dry matter intake (DMI) and effect of residual feed intake (RFI) classification on reproductive and performance traits, RFI was predicted by measuring individual dry matter intake (DMI) and average daily gain (ADG) using 186 Brangus heifers from two southeastern farms over a 70 d test period during 2014 and 2015. Results from standard 70 d DMI intake trials were compared to shortened test length periods of 14, 28, 42 and 56 d by regressing 70 d values of RFI, ADG and DMI on each shortened test length. Test length to predict RFI can be shortened to 56 d without loss of prediction accuracy (R=0.93 (P < 0.0001), R 2 = 0.90, rp= 0.95 (P < 0.0001), and rs= 0.95 (P < 0.0001)). Including 70 d ultrasound 12 th rib fat (UBF) in prediction of RFI, along with DMI and metabolic midweight, accounted for an additional 2% of model variation suggesting inclusion of UBF measurements is warranted. There were no significant differences for ADG, beginning or ending weight or age at first calving for heifers classified as efficient, average or inefficient based on RFI values. This suggests using RFI as a measure of efficiency will not affect other economically important traits. DMI was significantly different (P< 0.001) between RFI classifications. Significant feed cost savings ($63.91) were realized between efficient and inefficient RFI heifers. Shortening the measurement period by 14 d also could provide additional feed cost savings ($11.62/hd) and allow additional animals to be measured for DMI each year.

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Regulation of Luteinizing Hormone Secretion in Prepubertal Heifers Fed an Energy-Deficient Diet1

Cited by 26 publications

References 20 publications

Endocrine basis for puberty in heifers and ewes

Endocrine basis for puberty in heifers and ewes

Effects of recombinant bovine somatotropin and dietary energy intake on growth, secretion of luteinizing hormone, follicular development, and onset of puberty in beef heifers2

004 Recommended Duration for Evaluating Feed Intake and Validating the Residual Feed Intake Model in Brangus Heifers

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