I. REPRODUCTION AND LAMB PRODUCTION Relationships among hemoglobin (Hb) genotypes and reproduction and production traits were examined in 294 four- and five-year-old North Country Cheviot, Dorset, Finnsheep or Romney x Suffolk or Columbia-type crossbred ewes. Hb BB ewe lambs were youngest at first estrus and Hb AA ewe lambs were...
Half Polypay ewe lambs were bred to Suffolk, North Country
Cheviot and Hampshire rams to lamb at about one year of age.
Type of birth-rearing significantly affected mortality by 70
days of age and all weights of lambs from birth to weaning.
The mortality rate at 70 days of age...
One thousand twenty-three lambing records of 351 ewes bred in a
rotational crossbreeding system involving Columbia or Targhee,
Hampshire and Finnish Landrace breeds were examined. A regression
approach was used to determine the effects of breeds and heterosis on
wool grade, greasy fleece weight, ewe weight at lambing, lambing date,...
Some effects of 171β-estradiol on ovine luteal function were
studied in five experiments.
Estradiol injected into ewes on days 11 and 12 of the estrous
cycle caused luteal regression in both intact and unilaterally hysterectomized
ewes indicating that the presence of one uterine horn permits
estradiol to cause luteolysis comparable...
A study was conducted during 1975 and 1976 to evaluate
the use of chemically cured pasture as a flushing feed for
ewes in western Oregon.
In 1975 (0.56 kg/ha) and 1976 (0.28 kg/ha) paraquat
was used to chemically cure hill pasture forage when perennial
ryegrass (Lolium perenne L.) and tall...
Two experiments were conducted to examine the effect of
a cyclopropenoid fatty acid on luteal cell function. In Exp.
1, 12 mature ewes were mated to a fertile ram, assigned to two
groups (n = 6/group) and laparotomized on day 18 of gestation.
Ewes with corpora lutea (CL) in both...
A series of trials was conducted with Polypay (P), Coopworth
(CP), Hampshire (H), and crossbred ewes over a two year period at three
locations to assess the effects of ewe body condition and pre-lambing
supplementation on ewe productivity. Supplementation trials were
conducted at all three locations in Year 1 using...
Two trials were conducted over consecutive years to examine the effects of ewe
body condition and post-mating nutrition on ovulation rates and embryo survival. Trial 1
used 146 Polypay ewes ranging in age from 5 to 8 years in a 3 x 2 factorial array of pre-mating
(high-H, low flushed-LF...
Two experiments were conducted to determine whether in
ewes uterine concentrations of estrogen and progesterone
receptors are affected by the presence of a conceptus or by
the hormonal milieu associated with extremes in photoperiod
to which ewes are exposed.
In Exp.1, nine mature ewes were unilaterally
ovariectomized by removing an...
Coopworth sheep, a newly available genotype, were compared with
other genotypes in two trials to assess cumulative lamb and wool
production and contributing components related to survival, reproduction
and growth, and for the effects of ewe body weight on reproductive traits.
In a third trial, various genotypes generated in the...