Studies in ovine fertility in agricultural regions of Western Australia : ovulation rate, fertility and lambing performance

1975 ◽  
Vol 26 (1) ◽  
pp. 189 ◽  
Author(s):  
DR Lindsay ◽  
TW Knight ◽  
JF Smith ◽  
CM Oldham
Keyword(s):  
Body Weight ◽  
Western Australia ◽  
Reproductive Performance ◽  
Ovulation Rate ◽  
Day Length ◽  
Multiple Ovulation ◽  
Agricultural Regions

A total of 29,500 ewes, of which 2049 were laparotomized, in 53 flocks were used to determine the extent by which variations in body weight and age of the ewes and the temperature and day length about the time of mating were associated with the number of ovulations per 100 ewes (ovulation rate) and reproductive performance of sheep in south Western Australia. Overall there were only 113.7?2.2 ovulations per 100 ewes in the flocks studied. Less than 3% of the ewes failed to ovulate, so that in general differences between flocks were due to differences in the rate of multiple ovulation. Flocks with high ovulation rates produced more lambs per 100 ewes. There were about six extra lambs per 100 ewes for every 10% increase in the ovulation rate. About 40% of these extra lambs were due to extra twins; the remainder were due to more ewes lambing. Both age and body weight of the ewes were significantly correlated with ovulation rate (r = 0.41, P < 0.01 and r = 0.42, P < 0.01, respectively) and all the parameters of reproduction studied. Each 5 kg difference in body weight was associated with 5.9 extra ovulations per 100 ewes (P < 0.01).

Studies in ovine infertility in agricultural regions in Western Australia: the influence of a supplement of lupins (Lupinus angustifolius cv. Uniwhite) at joining on the reproductive performance of ewes

1975 ◽  
Vol 26 (3) ◽  
pp. 567 ◽  
Author(s):  
TW Knight ◽  
CM Oldham ◽  
DR Lindsay
Keyword(s):  
Body Weight ◽  
Western Australia ◽  
Reproductive Performance ◽  
Dietary Supplementation ◽  
Lupinus Angustifolius ◽  
Ovulation Rate ◽  
Mineral Supplement ◽  
Nitrogen Levels ◽  
Wool Growth ◽  
Agricultural Regions

The dietary supplementation of groups of 200 ewes with lupins (0.23 or 0.45 kg per head per day) just prior to and during joining increased the ovulation rate by 8–25 ovulations per 100 ewes and the number of lambs born increased by 5–23 lambs per 100 ewes joined. The increase in the number of lambs born had two components: (i) an increase in number of ewes lambing and (ii) an increase in the number of twin births. Another study suggested that feeding the lupin supplement during joining gave larger increases in the reproductive performance of the ewes, especially in number of ewes lambing, than feeding the supplement of lupins before joining. The increases in reproductive performance following lupin supplementation were not associated with differences or changes in body weight or with differences in the rate of wool growth. The feeding of a barley + urea + mineral supplement that provided 25% more digestible energy than the lupin supplement and similar nitrogen levels, but with 50% of the nitrogen in the form of urea, resulted in no increase in the reproductive performance of the ewes.

THE ACCUMULATIVE EFFECT OF FINNSHEEP BREEDING IN CROSSBREEDING SCHEMES: REPRODUCTIVE PERFORMANCE

1988 ◽  
Vol 68 (1) ◽  
pp. 69-81 ◽  
Author(s):  
MOHAMED H. FAHMY ◽  
JACQUES J. DUFOUR
Keyword(s):  
Body Weight ◽  
Mortality Rate ◽  
Key Words ◽  
Litter Size ◽  
Reproductive Performance ◽  
Conception Rate ◽  
Ovulation Rate ◽  
Genetic Groups ◽  
Linear Regressions ◽  
Size At Birth

Reproductive performance and body weight were studied on 361 ewes, representing Finnsheep (F), DLS (a population of 1/2 Dorset, 1/4 Leicester, 1/4 Suffolk) and seven combinations ranging from 1/8 to 7/8 Finnsheep breeding. Conception rate in yearlings was 61.5% for DLS compared to 89.0% for F with the crosses being intermediate. Conception rate in older ewes was similar in the different genetic groups (avg. 94%). Ovulation rate and litter size at birth of DLS ewes were 1.72 and 1.44 lambs, which was less than half those of F ewes (3.51 and 2.86 lambs, respectively). Both traits increased progressively with an increase in F breeding in crosses and with advances in age. DLS ewes weaned 1.22 lambs compared to 2.03 lambs for F ewes and 1.84 lambs for 4/8 F ewes. The heaviest litters at weaning (31.7 kg) were raised by 4/8 F ewes, followed by 7/8 F (30.8 kg) while those raised by DLS ewes weighed 23.0 kg and F ewes 29.1 kg. Percentage of ova lost per ewe mated averaged 24% and ranged between 18% (DLS and 1/8 F) and 29% (6/8 F). About 3.6% of lambs were born dead and a further 13.8% died before weaning. Preweaning mortality rate was highest in F (22.9%) and lowest in 3/8 F (9.4%). Average kilograms of lambs weaned per ewe exposed was highest in 4/8 F (27.6 kg) followed by F (26.0 kg), whereas that of DLS was the lowest at 18.1 kg. The 4/8 F cross showed 25% heterosis in kg of lambs weaned per ewe exposed and 52.5% increase over DLS. Significant positive linear regressions were calculated for ovulation rate, litter size and preweaning mortality rate on proportion of Finnsheep breeding in crosses. The relation was quadratic for percent ova lost and lamb mortality at weaning. Yearling DLS females weighted 36 kg compared to 44 kg for F yearlings. However, at 5 yr of age DLS ewes weighed 62 kg, 5 kg heavier than F ewes. The heaviest ewes at all ages were the 4/8 F (45 kg at 1 yr, 65 kg at 5 yr). Key words: Reproduction, DLS sheep, Finnsheep, crossbreeding, heterosis, repeatabilities

scholarly journals Ovulation rate of lines of mice selected for testis weight

1976 ◽  
Vol 27 (1) ◽  
pp. 23-32 ◽  
Author(s):  
A. B. M. Mafizul Islam ◽  
W. G. Hill ◽  
R. B. Land
Keyword(s):  
Body Weight ◽  
Reproductive Performance ◽  
Genetic Correlations ◽  
The Body ◽  
Ovulation Rate ◽  
Testis Weight ◽  
Testis Size ◽  
Realized Heritability ◽  
Breeding Programmes ◽  
The Mean

SUMMARYSelection was practised in two replicates for both high and low testis weight in the mouse. Typically 7 males were selected out of 30 recorded for a total of 5 generations. From an initial average of 191 mg the mean divergence between high and low lines reached 112 mg, with a realized heritability of 0·52. The ovulation rate of the lines changed in the same direction as that of selection, the mean divergence was 2·0 eggs in primiparous females in generation 4 and 1·6 in nulliparous females in generation 5. Correlated changes in the body weight of both sexes also occurred but were inadequate to account for the observed change in ovulation rate. The genetic regressions of ovulation rate on testis weight were estimated to be 2·9 and 14 eggs/100 mg in primiparous and nulliparous females, respectively, which, along with data from other experiments, correspond to genetic correlations between testis weight and ovulation rate of 0·50 and 0·25 respectively. There were no correlated changes in litter size. The possibility of using male testis size in breeding programmes to improve female reproductive performance is discussed.

scholarly journals Effects of selection on growth, body composition and food intake in mice: II. Correlated responses in reproduction

1984 ◽  
Vol 44 (1) ◽  
pp. 73-85 ◽  
Author(s):  
Forbes D. Brien ◽  
Gillian L. Sharp ◽  
William G. Hill ◽  
Alan Robertson
Keyword(s):  
Body Composition ◽  
Body Weight ◽  
Food Intake ◽  
Litter Size ◽  
Reproductive Performance ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Primary Reason ◽  
Correlated Responses ◽  
Fat Percentage

SummaryFemale reproductive performance is reported in mice selected for ten generations for one of three criteria: either appetite (A), fat percentage (F) or total lean mass (P). For each criterion lines were selected for high (H) or low (L) performance, with contemporary unselected controls (C). In the A and P lines, litter size changed in the direction of the selected criterion, the changes being larger and more rapidly established in the A than in the P lines. At generation 10, the differences in litter size between high and low lines were 2·6 live young born in the A lines, and 1·0 live young born in the P lines. The differences in 6-week weight between the high and low lines were 3·5 g in the A lines, 6·5 g in the P lines. Changes in ovulation rate were the primary reason for changes in litter size, the differences between the high and low lines being 3·8 corpora lutea for the A lines, and 3·1 corpora lutea for the P lines. Fitting body weight at mating as a covariate within lines in the analysis of ovulation rate and live foetus number removed the differences between the high and low selected P lines, but not those in the A lines. The high and low selected A and P lines did not differ in prenatal survival. There were no consistent differences in litter size, ovulation rate or pre-natal survival in the F lines.

The effects of body weight and level of nutrition before, during, and after joining on ewe fertility

1967 ◽  
Vol 7 (25) ◽  
pp. 126 ◽  
Author(s):  
ID Killeen
Keyword(s):  
Body Weight ◽  
Reproductive Performance ◽  
Ovulation Rate ◽  
Multiple Birth ◽  
Corpora Lutea ◽  
Body Weights ◽  
Before And After ◽  
Independent Effects ◽  
Experimental Treatments ◽  
High Level

Four experiments were designed to assess the independent effects of body weight and nutritional level on the reproductive performance of Border Leicester x Merino ewes. Ewes in experiments 1, 2, and 3 were joined in summer (December-January) and in experiment 4 in autumn (March-April). The reproductive performance of two groups of ewes in experiment 1, joined at different body weights, was assessed from mating and lambing data. A factorial (3 x 2 x 2) design was used for experiments 2, 3, and 4. The experimental treatments consisted of different levels of nutrition applied before and after mating. The reproductive performance of ewes in experiment 2 was assessed from mating and lambing data. Ewes in experiments 3 and 4 were slaughtered 19-28 days after mating, and their genitalia were observed for presence of corpora lutea and embryos. Body weight at mating and level of nutrition during three weeks before mating independently affected the multiple birth or ovulation rate. High body weight at mating was consistent with a high multiple birth or ovulation rate, and a higher proportion of the ewes receiving a high level of nutrition during the three weeks before mating (i.e. flushed ewes) had multiple births or multiple ovulations. The results also demonstrated that above 90-100 lb, the proportion of ewes mating and becoming pregnant was relatively independent of body weight at joining. The level of nutrition and body weight had only minor effects on early reproductive failure, but there was a higher proportion of egg wastage from multiple ovulation ewes than from single ovulation ewes.

Response of ewes to lupin supplementation at different times of the breeding season

1982 ◽  
Vol 22 (117) ◽  
pp. 264 ◽  
Author(s):  
PB Gherardi ◽  
DR Lindsay
Keyword(s):  
Body Weight ◽  
Breeding Season ◽  
Western Australia ◽  
Ovulation Rate ◽  
Mediterranean Environment ◽  
Natural Pasture ◽  
Australian Sheep ◽  
The Mediterranean ◽  
Better Than

Groups of 100 ewes grazing natural pasture in southern Western Australia were fed supplements of 750 g lupin grain for nine consecutive days every six weeks from October 1975-March 1976 to test whether the consistently low ovulation rate in West Australian sheep would vary with season if nutrition were better than normal. The ovulation rate of unsupplemented control ewes was from 1.05- 1.13 and did not vary significantly with season. Ewes responded significantly to supplementation and this response was unrelated to changes in body weight and varied in magnitude with season. It was about 20% in October, January and March but not significant in December. It is concluded that ovulation rates in pasture-fed sheep in the Mediterranean environment of southern Western Australia can vary with season, but only when the sheep are supplemented.

Comparison of the progeny of Peppin and Bungaree Merino ewes when mated to Border Leicester rams

1981 ◽  
Vol 21 (110) ◽  
pp. 280 ◽  
Author(s):  
RW Hodge ◽  
KT Beard
Keyword(s):  
Body Weight ◽  
Reproductive Performance ◽  
Ovulation Rate ◽  
Multiple Births ◽  
Retail Cuts

Three hundred and thirteen Peppin, and two hundred and eighty-seven Bungaree Merino ewes were mated to Border Leicester rams in February 1974. The first cross lambs were weaned in November 1974 and grazed on pasture. Twenty-four first cross male lambs of each strain were slaughtered over a range of liveweights, and carcase characteristics recorded. The reproductive performance of the first cross ewes was recorded over a period of 5 years. The parent Bungaree ewes had significantly more multiple births and weaned 10% more lambs per 100 ewes lambed than did the parent Peppin ewes. The carcases of the first cross Bungaree male lambs contained a higher percentage of retail cuts and less fat trim than the first cross Peppin male lambs. More of the Bungaree first cross ewes reached puberty before 12 months of age (P < 0.01) they grew significantly faster, attained a higher mature body weight and grew more wool than did the Peppin cross ewes (P < 0.01 ). No significant differences could be detected between the two strains of first cross ewes in terms of onset of oestrus, ovulation rate or number of lambs born. The lambs reared by the Bungaree cross ewes were significantly heavier (P < 0.01) at 12- 13 weeks of age than those raised by the Peppin cross ewes.

Effect of active or passive immunization against steroids on reproductive performance of ewes in different levels of body condition at mating

1986 ◽  
Vol 43 (2) ◽  
pp. 285-292 ◽  
Author(s):  
S. M. Rhind ◽  
B. A. Morris ◽  
Jill Clayton ◽  
J. M. Doney ◽  
R. G. Gunn ◽  
...  
Keyword(s):  
Body Condition ◽  
Reproductive Performance ◽  
Body Condition Score ◽  
Passive Immunization ◽  
Treated Group ◽  
Ovulation Rate ◽  
Control Group ◽  
Absolute Increase ◽  
Wide Range ◽  
Antibody Titres

ABSTRACTBorder Leicester × Scottish Blackface (Greyface) ewes of three groups, each comprising 118 animals in a wide range of body condition scores, were mated at a synchronized oestrus in mid October. The ewes were passively immunized against testosterone (group P), actively immunized against androstenedione (group F), or not treated (group C). All ewes were slaughtered at return to service or at 35 to 45 days of pregnancy and ovulation rates and numbers of embryos present were determined. Mean ovulation rates of ewes in group P were higher than in those in group C (P < 0·05) and this difference was evident at most levels of body condition. The absolute increase in ovulation rate, compared with the control group, was similar at all condition scores. Mean ovulation rates of ewes in group F were higher than those in group C (P < 0·001) and the magnitude of the increase was greater in ewes in higher condition scores. The incidence of ova wastage was variable but differences between treatments in mean ovulation rate were generally reflected in mean litter size. The conception rates of immunized ewes were depressed compared with those of control animals, particularly in ewes with a body condition score less than 3·0 at mating. Consequently, there was no improvement in the potential lambing rate of immunized ewes following only one cycle of mating. Circulating antibody titres were not related to conception rate or body condition at mating and were related to ovulation rate only in group F ewes. It is concluded that immunization against steroids, using either passive or active techniques, can improve the reproductive performance of individual ewes but improvement in the performance of the flock as a whole may only be achieved under optimal conditions of nutrition and season.

Sign in / Sign up

Export Citation Format

Share Document