A comparison of plasma prolactin, LH and progesterone concentrations during oestrus and early pregnancy in ewe lambs and ewes

1993 ◽  
Vol 57 (2) ◽  
pp. 281-286 ◽  
Author(s):  
M. C. G. Davies ◽  
N. F. G. Beck
Keyword(s):  
Pulse Rate ◽  
Early Pregnancy ◽  
Reproductive Performance ◽  
Ovulation Rate ◽  
Plasma Prolactin ◽  
Progesterone Concentration ◽  
Plasma Progesterone ◽  
Ewe Lambs ◽  
Plasma Hormone

AbstractAn investigation was conducted to compare, the LH, prolactin and progesterone profiles of ewe lambs with ewes during oestrus and early pregnancy. Peak LH concentration was significantly lower (P < 0·05) and duration of release tended to be shorter during oestrus in ewe lambs. Furthermore, this smaller LH peak tended to be associated with a lower ovulation rate. LH pulse rate, amplitude and concentration were similar in both groups during day 13 of pregnancy. However, LH concentration was higher in ewe lambs compared with ewes on day 28 of pregnancy. Peak prolactin concentration was lower during oestrus in ewe lambs (P < 0·05) but there was no difference between the two groups during early pregnancy. Plasma progesterone concentrations were similar in both groups until day 13 of pregnancy. Thereafter, mean progesterone concentration was lower, from day 14 to 30, in the ewe lambs (P < 0·05). These results indicate that in ewe lambs and ewes maintained under identical conditions plasma hormone profiles differ during oestrus and early pregnancy. Moreover, these differences probably contribute towards the lower reproductive performance of ewe lambs.

A note on attainment of puberty of september-born early-maturing ewe lambs in relation to level of nutrition

1991 ◽  
Vol 53 (3) ◽  
pp. 407-409 ◽  
Author(s):  
F. Forcada ◽  
J. A. Abecia ◽  
L. Zarazaga
Keyword(s):  
Sexual Activity ◽  
Breeding Season ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Plasma Progesterone ◽  
Ewe Lambs ◽  
Early Maturing ◽  
Age At Puberty

The attainment of puberty in September-born early-maturing ewe lambs was studied at Zaragoza (latitude 41° 40' N). Thirty twin Salz females were allocated to two groups receiving two nutrition levels after 3 months of age: high (500 g/day lucerne hay and 500 g/day concentrate) (H) and low (500 g/ day lucerne hay) (L). Oestrus was detected daily by aproned rams. Corpora lutea were counted after oestrus and plasma progesterone levels monitored each week.In the first breeding season (January to February) the percentage of females showing sexual activity (silent emulation or oestrus and ovulation) was higher in the H compared with the L group (67 and 20%; P < 0/05). Nonpubertal oestrus before the main breeding season was detected in 67% of animals. In the main breeding season and for H and L groups respectively, percentage of females showing silent ovulation before puberty was 67 and 33% and mean age at puberty extended to 319 (s.e. 4-8) and 314 (s.e. 3·7) days. Ovulation rate at puberty was 1·73 (s.e. 0·13) and 1·33 (s.e. 0·15) respectively (P < 0·05).

SEQUENTIAL CHANGES IN PLASMA PROGESTERONE IN THE COW DURING THE ESTROUS CYCLE, PREGNANCY, AT PARTURITION, AND POST-PARTUM

1972 ◽  
Vol 52 (4) ◽  
pp. 645-658 ◽  
Author(s):  
H. A. ROBERTSON
Keyword(s):  
Estrous Cycle ◽  
Early Pregnancy ◽  
Luteal Phase ◽  
Post Partum ◽  
Progesterone Concentration ◽  
Cyclic Activity ◽  
Gradual Decline ◽  
Plasma Progesterone ◽  
Peripheral Plasma ◽  
Estrous Behavior

The progesterone concentration in peripheral plasma has been measured sequentially in individual cows during the estrous cycle, gestation, at parturition, and post-partum. During the estrous cycle the concentration was lowest just before, during, and just after estrus when the level (0.1–0.4 ng/ml) was similar to that found in three ovariectomized cows. The concentration commenced to rise on the 4th–6th day (day of estrus = 1st day), reached a peak of 3–6 ng/ml on the 11th–13th day, and dropped rapidly over a 24–48-hr period to a basal value 24–72 hr before the next estrus. In early pregnancy, the plasma progesterone concentration was similar to the maximum levels found during the luteal phase of the estrous cycle. Between 90 and 150 days there was an indication of a decline to a relatively low plasma progesterone concentration followed by a variable rise. Prior to parturition, there was a gradual decline over a period of 35–70 days reaching a level of <2.0 ng/ml the day before parturition. Following parturition, the level remained at <0.5 ng/ml until the first sign of the resumption of cyclic activity. The time for this to occur was very variable (20–>60 days). Although not conclusive, the evidence favors the view that for estrous behavior to occur, estrus must be preceded by luteal activity. The discharge of mucus can occur without previous luteal activity.

A note on reproductive performance and plasma progesterone level during early pregnancy of Scottish Blackface and Cheviot ewes in relation to body condition and level of nutrition prior to mating

1983 ◽  
Vol 37 (3) ◽  
pp. 455-458 ◽  
Author(s):  
S. M. Rhind ◽  
R. G. Gunn ◽  
J. M. Doney
Keyword(s):  
Treatment Group ◽  
Body Condition ◽  
Early Pregnancy ◽  
Reproductive Performance ◽  
Weight Maintenance ◽  
Live Weight ◽  
Corpora Lutea ◽  
Plasma Progesterone ◽  
Condition Score ◽  
Maintenance Ration

ABSTRACTSeventy-nine Scottish Blackface and 79 North × South Country Cheviot ewes were fed to increase their mean condition score by 0·5 over periods of either 4 (M/H group) or 8 (I group) weeks prior to mating. Thereafter, they were fed a live-weight maintenance ration until they were slaughtered at 50 to 65 days after mating. Reproductive tracts were recovered, corpora lutea counted and embryos counted and examined. Plasma progesterone levels were monitored at selected times after mating. The proportion of ewes in each treatment group that were pregnant at the time of slaughter was similar (0·75 to 0·83) but there was evidence of differences in the pattern of reproductive failure with treatment. The proportion of non-pregnant ewes which had apparently been pregnant initially was 0·55 in the M/H group compared with only 0·27 in the I group. Circulating progesterone levels were not affected by premating nutritional treatments but differed with breed.

THE CONCENTRATION OF PROGESTERONE IN THE PERIPHERAL PLASMA OF THE PREGNANT EWE

1969 ◽  
Vol 45 (3) ◽  
pp. 449-457 ◽  
Author(s):  
J. M. BASSETT ◽  
TANA J. OXBORROW ◽  
I. D. SMITH ◽  
G. D. THORBURN
Keyword(s):  
Protein Binding ◽  
Early Pregnancy ◽  
Luteal Phase ◽  
Progesterone Concentration ◽  
Plasma Progesterone ◽  
Peripheral Plasma ◽  
High Concentrations ◽  
Pregnant Ewe

SUMMARY The progesterone concentration in the peripheral plasma of ewes throughout pregnancy has been determined by a protein-binding method. Plasma progesterone concentrations during the first 50 days of pregnancy (2–3 ng./ml.) were not significantly higher than peak concentrations during the luteal phase in cycling non-pregnant ewes, but there was no decrease in the concentration 15–20 days after mating as occurs in non-pregnant ewes. Between 50 and 120 days after mating the plasma progesterone concentration increased steadily to values 2–5 times that found in early pregnancy. These high concentrations were maintained until lambing. A decrease in progesterone concentration during the week preceding lambing was usually, but not always, observed. Mean plasma progesterone concentrations during the last 50 days of pregnancy in ewes with twins were approximately twice those in ewes with a single foetus.

The effect of long photoperiod or bromocryptine treatment on prolactin concentration and fertility in ewe lambs mated at induced oestrus

1995 ◽  
Vol 60 (2) ◽  
pp. 209-214
Author(s):  
N. F. G. Beck ◽  
M. C. G. Davies ◽  
B. Davies
Keyword(s):  
Control Group ◽  
Corpora Lutea ◽  
Plasma Prolactin ◽  
Progesterone Concentration ◽  
Embryo Survival ◽  
Crown Rump Length ◽  
Growth And Survival ◽  
Ewe Lambs ◽  
Group B ◽  
Long Photoperiod

AbstractAn investigation was conducted into the effects of increasing plasma prolactin concentration with long photoperiod or suppressing it with bromocryptine on the fertility of ewe lambs. One hundred and twenty dim Forest ewe lambs were divided into three groups: group C was kept as a control; group L was exposed to a long photoperiod (16 h light: 8 h dark) and group B was given daily injections of 1 mg bromocryptine from 12 days before until 21 days after mating. All three groups were mated in late November, 30 days after housing, following progestagen/PMSG treatment. Post-mating prolactin concentrations were significantly higher in group L and lower in group B compared with group C (P > 0·05). There was a tendency for pregnancy rate and the number of corpora lutea to be represented by viable foetuses to be lower in group L than in group C (P < 0·05). Furthermore, post-mating progesterone concentration was higher in this group compared with those in group C (P > 0·05). In a second experiment, 100 Welsh Χ Texel ewe lambs were given treatment C or L. Embryo survival tended to be lower and crown rump length, embryo weight and amniotic sac width were reduced at 25 days post mating in the animals given treatment L, compared with those given treatment C (P < 0·05). The combined results of the experiments indicated that fewer corpora lutea were represented by viable embryos or foetuses in group L than in group C (P < 0·05). These results suggest that embryo growth and survival is reduced in animals bred under a long photoperiod.

Early reproductive losses are a major factor contributing to the poor reproductive performance of Merino ewe lambs mated at 8–10 months of age

2014 ◽  
Vol 54 (6) ◽  
pp. 762 ◽  
Author(s):  
B. L. Paganoni ◽  
M. B. Ferguson ◽  
S. Fierro ◽  
C. Jones ◽  
G. A. Kearney ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
First Record ◽  
Reproductive Rate ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Mating Period ◽  
Breeding Values ◽  
Pregnancy Failure ◽  
Ewe Lambs ◽  
Reproductive Losses

The reproductive performance of Merino ewe lambs is lower than that achieved by mature ewes and is highly variable. It is likely that embryo loss represents a major source of reproductive wastage in Merino ewe lambs, but to our knowledge no studies have attempted to determine when the major reproductive losses occur or identify predisposing factors that are likely to lead to high rates of pregnancy failures in ewe lambs. After characterising where reproductive losses occurred in Merino ewe lambs mated at 8–10 months of age, we tested the hypothesis that pregnancy failure in ewe lambs is influenced by nutrition and liveweight change around conception and the genetic potential for growth of the ewe lamb. Two-hundred and twenty-four Merino ewe lambs born from 10 sires with Australian Sheep Breeding Values were teased for 14 days using vasectomised rams, and then fed two different diets for 68 days during mating. All ewe lambs were weighed and the appearance of crayon marks on their rump was recorded most days. Blood samples for progesterone assay were collected on Days 5, 12 and 17 after the first record of a crayon mark. Ultrasonography using a trans-rectal probe was used to measure the number of corpora lutea present, as a proxy for ovulation rate, 9 days after the first record of a crayon mark during the mating period. A further trans-rectal ultrasonography was undertaken 30 days after marking from the entire ram to determine pregnancy status and count the number of embryos. Over the entire mating period 54% of ewe lambs were pregnant with 66 fetuses per 100 ewes mated. The average ovulation rate was 150% however up to 84% of this potential was lost by weaning and the major contributor to this apparent deficit was the loss that occurred during the first 17 days after mating. Pregnancy failure was not significantly related to nutrition or liveweight change during mating however, there were significant differences in pregnancy failure between different sire groups. Pregnancy failure was significantly less for ewe lambs from sires with higher breeding values for weight and fat at post-weaning age (8–10 months). Only 60% of ewe lambs had achieved puberty when rams were introduced and only 83% by 35 days after mating. In addition, almost half of the ewe lambs that were mated for the first time during the first 35 days after rams were introduced, but failed to get pregnant, then seemed to skip a cycle or did not cycle again before the end of the 68-day mating period. Liveweight at introduction of entire rams was positively related to fertility, ovulation rate and reproductive rate. This study confirms that selection of sires with higher breeding values for post-weaning weight and fat will increase the fertility and reproductive rate of Merino ewe lambs mated at 8–10 months. This response is due in part to enhancing the onset of puberty and increasing the proportion of ewe lambs cycling at the start of mating and reducing pregnancy failure.

REPRODUCTIVE PERFORMANCE OF BOOROOLA × FINNISH LANDRACE AND BOOROOLA × SUFFOLK EWE LAMBS, HETEROZYGOUS FOR THE F GENE, AND GROWTH TRAITS OF THEIR THREE-WAY CROSS LAMBS

1990 ◽  
Vol 70 (1) ◽  
pp. 55-65 ◽  
Author(s):  
F. CASTONGUAY ◽  
F. MINVIELLE ◽  
J. J. DUFOUR
Keyword(s):  
Litter Size ◽  
Reproductive Performance ◽  
Growth Traits ◽  
Average Daily Gain ◽  
Ovulation Rate ◽  
The Other ◽  
F Gene ◽  
Ewe Lambs ◽  
Genetic Groups ◽  
Significant Difference

Reproductive performance of Booroola × Finnish Landrace (BFL, n = 19) and Booroola × Suffolk (BS, n = 18) ewe lambs heterozygous for the F gene were compared to Finnish Landrace (FL, n = 14) and Suffolk (S, n = 26) purebred controls. FL lambs reached puberty earlier (211.3 d, P < 0.001) than the other genetic groups (237.8, 233.0 and 232.9 d for S, BS and BFL, respectively) whereas weight at puberty was lower (P < 0.001) for BFL, FL and BS (36.8, 36.7 and 47.0 kg, respectively) than for S (61.1 kg). About 95% of BFL and BS ewe lambs had at least one record of three ovulations or more over the first three estruses, including puberty. Mean ovulation rates at breeding (second estrus after puberty) to a Hampshire (H) ram were 3.8, 3.3, 2.2 and 1.7 for BFL, BS, FL and S, respectively (BFL and BS vs. FL and S, P < 0.001). The corresponding litter sizes at birth were 2.5, 2.1, 1.6 and 1.3 (BFL and BS vs. FL and S, P < 0.001) which reflected a higher embryonic loss in the Booroola crosses. Percentage ova loss ranged between 32.8% (BFL) and 12.8% (S) and was related to the level of prolificacy. Lamb mortality at birth was high in BFL (23.7%) compared to BS, FL and S (6.5, 0.0 and 0.0%, respectively, P < 0.001). Litter size at weaning (50 d of age) averaged 1.9, 1.8, 1.5 and 1.3 for BS, BFL, FL and S ewe lambs (BS vs. S, P < 0.02). Growth performance of H-sired progeny from the four genetic groups of ewes showed that H × S lambs had the highest average daily gain in both preweaning and postweaning periods (preweaning ADG: 349.9 g d−1; postweaning ADG: 332.1 g d−1) while the other genotypes of lambs performed equally (preweaning ADG: 267.4, 249.5 and 246.8 g d−1 for H × FL, H × BFL and H × BS, respectively; postweaning ADG: 281.2, 276.8 and 281.8 g d−1 for the same genetic groups). Overall productivity of ewe lambs in terms of kilograms of lamb produced showed a slight, nonsignificant, advantage for Booroola-cross ewe lambs (55.8 and 54.5 kg for BS and BFL) over purebred S (51.6 kg) and FL (44.9 kg). These results indicate that ovulation rate and litter size can be increased by incorporating F gene in both prolific (FL) and nonprolific (S) background genotypes without resulting in any significant difference in total weight of lamb produced per ewe. Key words: Sheep, ewe productivity, Booroola, ovulation rate, crossbreeding

242. Reproductive performance of Australia Cashmere goats supplemented with lupin grain

2008 ◽  
Vol 20 (9) ◽  
pp. 42
Author(s):  
M. Shikh Maidin ◽  
A. Chadwick ◽  
P. C. Khaiseb ◽  
P. A. Hawken ◽  
G. B. Martin
Keyword(s):  
Early Pregnancy ◽  
Reproductive Performance ◽  
Opposite Effect ◽  
Nutritional Supplement ◽  
Supplementary Feeding ◽  
Ovulation Rate ◽  
Control Group ◽  
Abdominal Ultrasonography ◽  
Cashmere Goats ◽  
And Control

The productivity of Cashmere goats depends on their reproductive performance, which, in turn, depends on their level of nutrition. Ovulation rate and pregnancy in sheep are both affected by nutrition, but little is known about the response of female goats (does) to supplementary feeding. The lupin group (n = 40) received 250 g lupin per head per day in addition to pasture whereas the control group (n = 40) received no nutritional supplement. Both groups were synchronised for 17 days with intravaginal progestagen pessaries. The supplement was fed for 21 days, commencing 7 days before the bucks were introduced and intravaginal pessaries were removed (Day –2). Does were expected to ovulate 2 days later on Day 0 and the bucks were removed on Day 3. Blood was sampled for progesterone every 3 days from buck removal (Day 3) until Day 18. Ovulation rate was assessed by trans-rectal ultrasonography on Day 13 and pregnancy was diagnosed by trans-abdominal ultrasonography on Day 61 of the experiment. Does supplemented with lupins had a numerically higher ovulation rate than does fed only on pasture, but this difference was not significant (1.76 ± 3.21 v. 1.52 ± 3.79; P > 0.05). Similarly, there was no difference in the numbers of does conceiving to the first service between the lupin and control group (89% v. 94%; P > 0.05). Progesterone concentrations on Day 12 were higher in does supplemented with lupins than does fed only pasture (6.29 ± 0.27 ng/mL v. 5.41 ± 0.27 ng/mL; lupin and control group; P < 0.05). In conclusion, lupin supplementation induced a numerical increase in ovulation rate but this difference failed to reach significance. Does supplemented with lupins had higher concentrations of progesterone during early pregnancy, which is the opposite effect to that previously reported in sheep.

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