Genetically mod clover, sheep submissions
Brian Sandle
Sellborne application to test genetically modified sheep but extra
Information is now being received until 3rd April 1995.
White clover has a goitrogenic effect - goitrogens in milk?
Permanent flock infertility following long-term grazing of oestrogenic
red clover - resistance transfer?
4 abstracts on oestrogenic food effects - prostatic hyperplasia,
persistent-estrus
The New Zealand Genetically Modified Organism (GMO) Interim Assessment
Group (IAG) has received an application from the New Zealand Pastoral
Agricultural Research Institute Ltd (AgResearch Grasslands) to conduct a
field test of white clover genetically modified for resistance to white
clover mosaic virus. The work is being undertaken in collaboration with
the Horticulture and Food Research Institute of New Zealand
(Hort+Research).
The field test is proposed to be conducted at the Aorangi Lowland
Research Farm, 15 km west of Palmerston North.
The closing date for public submissions is Thursday 13 April 1995.
Persons interested in the details of this can get details from
B J Forde
Chairperson, Interim Assessment Group
for Secretary for the Environment
Ministry for the Environment
84 Boulcott St, P.O.Box 10362 Wellington, New Zealand
Telephone 644-473-4090, Fax 644-471-0195.
I am not an expert in these matters, but I note the wide distribution of
white clover. I hope some of you will be able to take thinking further
on this matter.
The number of people who submitted on the Sellborne application to test
genetically modified sheep was quite low (14), but extra information is
now being received until 3rd April 1995.
The main issues raised through the submission process were:
* Maori objections to genetic manipulation in general and specifically
the use of human genetic material in transgenic manipulation.
* the lack of forthcoming benefits to New Zealand.
* the risk of damaging our scrapie-free status (through loss of
containment) and the resulting negative impact on the New Zealand sheep
industry, and
* animal welfare concerns
* Maori ownership of their genetic endowment, and indigenous flora and
fauna.
Note that the new legislation in consideration for hazardous substances
and new organisms by the Select Committee does not have ethical input
other than from the hoped-for "Treaty of Waitangi or kaupapa Maori"
input.
At risk of getting things out of context in the clover submission I
quote some parts.
> D9. No detrimental consequence can be envisaged should modified white
> clover plants remain at the trial site after the conclusion of the
> trial.
> D10. The trial site will be monitored for two years following the
> field testing for the appearance of volunteer white clover plants
> which will be removed and destroyed or herbicide sprayed.
> E9. A five year span without white clover sowings and annual
> cultivation and spraying with herbicide is required to reduce
> volunteers to less than 1 per 10 square metres.
Is it possible that any of the ripening seed heads cold be missed
and seed escape? I question is it possible that the first seed spread
volunteers of this new plant could appear after two years?
Can birds distribute clover seed?
> D5. Modified white clover is expected to be more productive and
> persistent and so decrease the competitiveness of cohabitants such as
> perennial ryegrass (Lolium perenne L.). The effect is expected to be
> small and not reduce perennial ryegrass survival.
The applicants must consider "End uses"
Note that white clover has a goitrogenic effect, especially on sheep,
and perhaps the regulatory effect of disease was a blessing in disguise.
Butler et al. "Goitrogenic effect of white clover (Trifolium repens l.),
N.Z.J.SCI.TECHNOL. SECT.A,38,793-802, 1957.
And goitrogens in milk may be a problem - in Tasmania school children
got worse goitre when fed iodine tablets and milk from marrow-stem kale
fed cows. This does not absolutely say that the goitrogens in the milk
from the kale caused the extra goitre. (It was the requirement for the
extra milk from the milk in schools scheme which was started which meant
the cows started to be fed on the kale.) - "Food" - Scientific American.
> II. C1. White clover crosses with other members of the genus with
extreme difficulty.
Note that if released it would be around for a long time - what if it
transferred its resistance to red clover?
The following citations and abstracts are taken from Biological
Abstracts on CD-ROM, produced by BIOSIS, the world's largest abstracting
and indexing company in the life sciences. BIOSIS produces over 500,000
citations per year from journals, meetings, books, and patents. Although
BIOSIS makes a diligent effort to provide a complete and accurate
representation of bioscientific and other literature, BIOSIS does not
guarantee the accuracy, adequacy, or completeness of any information.
For more information, contact BIOSIS at 2100 Arch Street, Philadelphia,
PA 19013, USA; telephone 1-800-523-4806 (U.S. and Canada), (215)587-4847
(Worldwide); World Wide Web URL:http://www.biosis.org; Internet e-mail:
in...@mail.biosis.org
TI: Effects of prolonged exposure of ewes to oestrogenic pasture:1.
Permanent flock infertility following long-term grazing of red clover
('Grasslands Pawera')-dominant pasture.
AU: Shackell-G-H; Kelly-R-W; Johnstone-P-D
SO: New Zealand Journal of Agricultural Research 36(4): 451-457
PY: 1993
LA: English
AB: Romney ewes grazed red clover (P) or mixed red clover/ryegrass (M)
pastures for about 6 months/year until mating in Year 4 (P) or 5 (M) of
a 6-year study. A further group grazed ryegrass/white clover (C) pasture
continuously throughout the study. At other times all animals grazed
ryegrass/white clover pasture as one mob. Ewes grazing P pasture were
consistently 3-6 kg heavier than ewes that grazed C pasture. Despite
similar proportions of ewes being marked by the ram, and similar
ovulation rates, during the first cycle of mating each year, ewes
grazing P pastures consistently showed increased returns to service
(+30%), increased barrenness (+30%), and fewer lambs born per ewe joined
(-0.5) than ewes grazing C pasture. Differences persisted after ewes
were removed from treatment pastures, indicating that infertility was
likely to be permanent.
TI: Effects of prolonged exposure of ewes to oestrogenic pasture: 2.
Occurrence of abnormalities of the external genitalia and altered mating
performance.
AU: Shackell-G-H; Wylie-J-G; Kelly-R-W
SO: New Zealand Journal of Agricultural Research 36(4): 459-464
PY: 1993
LA: English
AB: Romney ewes grazed pasture initially containing 0 (C), 30 (M), or
60% (P) Pawera red clover for c. 6 months per year (spring-autumn)
during the first 4 (P) or 5 (M) years of a 6-year study. When not
grazing red clover, ail animals grazed C-type pastures. In Years 3d,
ewes were scored on a subjective 0-3 scale for vaginal abnormalities.
More of the animals grazing M pasture scored 1 or higher each year
compared to the ewes on C pasture (P lt 0.001). Similarly, more of the
ewes grazing P herbage were scored 2 or higher than either of the other
two groups (P lt 0.001). A greater proportion of the ewes on the P sward
were mated more than once at each joining, compared with the other two
groups (P lt 0.01 in Year 3; P lt 0.001 in all other years) and
consequently there were differences in the mean number of times each ewe
was mated. Long-tenn grazing of oestrogenic red clover results in both a
high incidence of abnormalities of the external genitalia and decreased
mating performance in ewes. However, these effects appear to be
independent of each other.
TI: Developmental estrogenization and prostatic neoplasia.
AU: Santti-R; Newbold-R-R; Makela-S; Pylkkaenen-L; McLachlan-J-A
SO: Prostate 24(2): 67-78
PY: 1994
LA: English
AB: The association of estrogens with benign prostatic hyperplasia and
prostatic cancer has been widely studied, but no conclusive evidence
exists for a role of estrogens in prostatic disease. This paper reviews
the literature and describes studies which have sought to show a
correlation of estrogens and alterations in the prostates of humans and
experimental animal models. Using the developmentally estrogenized mouse
model, we propose an alternative role for estrogens as a predisposing
factor for prostatic diseases: estrogen exposure during development may
initiate cellular changes in the prostate which would require estrogens
and/or androgens later in life for promotion to hyperplasia or
neoplasia. Thus, the critical time for estrogen action would be during
the development of the prostatic tissue. We further suggest that
estrogen-sensitive cells may remain in the prostate and be more
responsive to estrogens later in life or less responsive to the normal
controlling mechanisms of prostatic growth.
TI: A phytoestrogen diet induces the premature anovulatory syndrome in
lactationally exposed female rats.
AU: Whitten-P-L; Lewis-C; Naftolin-F
SO: Biology of Reproduction 49(5): 1117-1121
PY: 1993
LA: English
AB: The effects of a phytoestrogen diet on sexual differentiation were
examined in lactationally exposed rat pups. Rat dams were provided a
semipurified diet containing the isoflavonoid coumestrol at a
concentration (0.01% ) previously found to be uterotrophic. Coumestrol
treatment did not significantly alter the time of vaginal opening,
although vaginal opening did occur at a lighter body weight. By 132 days
of age, 83% of coumestrol-treated females exhibited the cornified smears
of a persistent estrous state. By contrast, 91% of control animals were
cycling regularly at 132 days of age. Estradiol stimulation failed to
elicit an LH elevation in the coumestrol-treated animals, suggesting the
possibility of neuroendocrine impairments. These findings indicate that
the female offspring of mothers fed a low-level phytoestrogen diet
during lactation manifest early and nearly universal disruption of
cyclicity of the persistent-estrus type.
Brian R.Sandle. prevention is better than cure.