Effects of Implanting Prepuberal Dairy Heifers with Anabolic Steroids on Hormonal Status, Puberty and Parturition

Heitzman, R.J.; Harwood, David; Kay, R. M.; Little, W.; Mallinson, C.B.; Reynolds, I. P.

doi:10.2527/jas1979.484859x

Cited by 21 publications

(17 citation statements)

References 10 publications

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“…Similarly, the ability of TBA to suppress ovulation in mature cows and rats has been attributed to its potent antigonadotrophic activity (Neumann, 1976;Reynolds et al, 1981;Peters, 1987) which, from a practical standpoint at least, is equivalent to its ability to suppress LH secretion. Thus, Heitzman et al ( 1979) found that 300 mg TBA, given just before puberty in control heifers, delayed puberty for 140 days after implant insertion. Had the slaughter date in the present study been postponed until all heifers had reached puberty, the mean delay might have been very similar to that reported by Heitzman et al (1979).…”

Section: Discussionmentioning

confidence: 99%

“…Thus, Heitzman et al ( 1979) found that 300 mg TBA, given just before puberty in control heifers, delayed puberty for 140 days after implant insertion. Had the slaughter date in the present study been postponed until all heifers had reached puberty, the mean delay might have been very similar to that reported by Heitzman et al (1979). The above results also illustrate the dangers of using first oestrus as an indicator of puberty in heifers given oestrogenic compounds, since they clearly demonstrate that zeranol delays first ovulation despite the fact that it has previously been shown to have no effect on the timing of first oestrus (Muncy et al, 1979;Fuller et al, 1980;Staigmiller et al, 1983;Deutscher et al, 1986).…”

Section: Discussionmentioning

confidence: 99%

“…The present data verify this hypothesis, by clearly demonstrating that TBA and zeranol delay the onset of puberty in beef heifers. Furthermore, since the compressed pellet-type implants which were used to deliver these compounds have an active lifespan of 60-100 days (Heitzman et al, 1979;Henricks et al, 1982;Heitzman et al, 1984), the time at which heifers in the TBA and zeranol treatment groups first ovulated corresponded roughly to the time at which the last implants would have expired.…”

Section: Discussionmentioning

confidence: 99%

“…Neither did any of the above authors examine the effect of zeranol on reproductive tract development in heifers. Although several authors have studied the effects of TBA on the ovulatory cycle of heifers (Heitzman et al, 1979;Reynolds et al, 1981;Peters, 1987) little is known of its effects on the oestrous cycle. The effect of exogenous oestradiol on reproduction in heifers is also poorly understood.…”

Section: Introductionmentioning

confidence: 99%

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Effects of oestradiol, zeranol or trenbolone acetate implants on puberty, reproduction and fertility in heifers

Morán¹,

Prendiville²,

Quirke³

et al. 1990

Reproduction

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Summary. The effects of anabolic agents on reproduction in beef heifers were determined by using 300 mg trenbolone acetate (TBA), 36 = 43\m=.\8and 39\m=.\4for age and weight respectively]. Heifers in Group 4 were older (P < 0\m=.\05), but not heavier (P > 0\m=.\05), while those in Groups 2 and 5 were both older (P < 0\m=.\005) and heavier (P < 0\m=.\005) than the controls at puberty. Age and weight at puberty were not different in heifers assigned to Groups 3 and 4, or to Groups 2 and 6. The proportion of heifers showing oestrus before puberty (prepubertal oestrus) were 3/15, 12/15, 6/12, 7/15, 10/13 and 11/11 in Groups 1\p=n-\6 respectively. Heifers in Groups 2 and 5 had higher incidences of prepubertal oestrus than controls, while those in other treatment groups were not different. There was no treatment effect on the incidence of silent ovulations, but the incidence of non\x=req-\ ovulatory oestrus, after puberty, was increased from 4/48 in Group 1 to 26/40 (P < 0\m=.\001),15/56 (P < 0\m=.\05) and 34/57 (P < 0\m=.\001) in Groups 2, 4 and 5, respectively. Heifers in Group 6 had a higher incidence of non-ovulatory oestrus (P < 0\m=.\05), but not of prepubertal oestrus, than did those in Group 2. The uteri of heifers in Groups 2 and 5 were lighter (P < 0\m=.\05) than those of controls, while the uteri and ovaries of Group 6 heifers were lighter (P < 0\m=.\05) than those of Group 2 heifers. Heifers in Group 3 had lighter ovaries than heifers in Group 4 (P < 0\m=.\05). It is concluded that anabolic agents delayed puberty, increased the incidence of non-ovulatory oestrus and retarded reproductive tract development when given to beef heifers from 84 days of age onwards.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of oestradiol, zeranol or trenbolone acetate implants on puberty, reproduction and fertility in heifers

Morán¹,

Prendiville²,

Quirke³

et al. 1990

Reproduction

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show abstract

“…use of this growth promotant in heifers reared as replacement breeding stock (Heitzman et al, 1979). Research investigators will no doubt continue to assess the potential of currently available and newly developed anabolic agents for use in feedlot heifers.…”

Section: Exogenous Hormonesmentioning

confidence: 99%

Manipulation of Endogenous and Exogenous Hormones for Red Meat Production

Schanbacher¹

1984

Journal of Animal Science

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SummaryGrowth and development of domestic livestock for red meat production are often discussed in the context of environmental factors, nutritional requirements, genetic potential and the anabolic agents affecting production efficiency. In this minireview, the effects of endogenous and exogenous hormones on animal growth are reviewed. The pituitary, pancreatic and gonadal hormones known to affect growth and(or) carcass composition are cited to illustrate and place into perspective the important contributions that the endocrine system makes to animal production. Manipulation of endogenous hormones through 1) administration of synthetic releasing and inhibiting peptides and 2) immunoneutralization techniques, will likely provide the livestock producer with new technological approaches for increasing red meat production. Researchers continue to evaluate the efficacy of natural and synthetic steroids, and combinations thereof, as suitable anabolic agents. In conclusion, several hormones of both endogenous and exogenous origin can be manipulated to improve or enhance growth and development of the meat-producing animal.

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The efficacy, mode of action and safety of non-steroidal non-antimicrobial growth promoters

1983

Vet Res Commun

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Effects of Implanting Prepuberal Dairy Heifers with Anabolic Steroids on Hormonal Status, Puberty and Parturition

Cited by 21 publications

References 10 publications

Effects of oestradiol, zeranol or trenbolone acetate implants on puberty, reproduction and fertility in heifers

Effects of oestradiol, zeranol or trenbolone acetate implants on puberty, reproduction and fertility in heifers

Manipulation of Endogenous and Exogenous Hormones for Red Meat Production

The efficacy, mode of action and safety of non-steroidal non-antimicrobial growth promoters

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