scholarly journals Abortion and Lamb Mortality between Pregnancy Scanning and Lamb Marking for Maiden Ewes in Southern Australia

Animals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 10
Author(s):  
Thomas Clune ◽  
Amy Lockwood ◽  
Serina Hancock ◽  
Andrew N. Thompson ◽  
Sue Beetson ◽  
...  
Keyword(s):  
Cohort Study ◽  
Reproductive Performance ◽  
Important Contributor ◽  
Ewe Lambs ◽  
Ewe Lamb ◽  
Overall Mortality

The contribution of abortions to the overall mortality of lambs born to maiden (primiparous) ewes in Australia remains unclear. This cohort study aimed to quantify abortion and lamb mortality for ewe lambs and maiden Merino two-tooth ewes. Lamb mortality from pregnancy scanning to marking were determined for 19 ewe lamb and 11 Merino two-tooth ewe flocks across southern Australia. Average lamb mortality from scanning to marking was 35.8% (range 14.3–71.1%) for the ewe lambs and 29.4% (range 19.7–52.7%) for the two-tooth ewes. Mid-pregnancy abortion was detected in 5.7% of ewes (range 0–50%) in the ewe lamb flocks and 0.9% of ewes (range 0–4.4%) in the two-tooth ewe flocks. Mid-pregnancy abortion affecting ≥2% of ewes was observed in 6/19 ewe lamb flocks and 2/11 two-tooth ewe flocks. Lamb mortality from birth to marking represented the greatest contributor to foetal and lamb mortality after scanning, but mid-pregnancy abortion was an important contributor to lamb mortality in some ewe lamb flocks. Variability between the flocks indicates scope to improve the overall reproductive performance for maiden ewes by reducing foetal and lamb losses. Addressing mid-pregnancy abortion may improve the reproductive performance in some flocks.

Single female offspring born to primiparous ewe-lambs are lighter than those born to adult multiparous ewes but their reproduction and milk production are unaffected

2012 ◽  
Vol 52 (7) ◽  
pp. 552 ◽  
Author(s):  
M. F. P. Loureiro ◽  
S. J. Pain ◽  
P. R. Kenyon ◽  
S. W. Peterson ◽  
H. T. Blair
Keyword(s):  
Milk Production ◽  
Reproductive Performance ◽  
Crude Protein ◽  
Female Offspring ◽  
Productive Performance ◽  
Single Female ◽  
Ewe Lambs ◽  
Ewe Lamb ◽  
Generation Offspring

Little is known about the long-term impacts of selecting progeny born to ewe-lambs (EL) as replacements. This study investigated whether being born to a ewe-lamb affected the liveweight, milk production and reproductive performance of the offspring to 3 years of age in comparison with those born to adult multiparous ewes. Twenty-seven and 28 single-born Romney ewe progeny (G1) were born to either EL or to adult ewes (AE), respectively. Offspring born to ewe-lambs (ELG1) were lighter (P < 0.001) at birth and up to 12 months of age compared with offspring born to adult ewes (AEG1). Reproductive performance of AEG1 and ELG1 did not differ in regards to puberty attainment, pregnancy rate and number of fetuses. First lactation milk production, fat, crude protein, total protein, casein, lactose and total solids yield did not differ (P > 0.05). The second generation offspring born to ELG1 and AEG1 did not differ in birthweight in the first parity, but it did differ in the second parity and those lambs born to ELG1 were heavier from birth to weaning compared with those lambs born to AEG1. Combined, these results indicate, in the animals used in our study that productive performance of ewes born to EL does not differ to 3 years of age to that of ewes born to AE.

Effect of timing of exposure to vasectomised rams and ewe lamb body condition score on the breeding performance of ewe lambs

2012 ◽  
Vol 52 (7) ◽  
pp. 471 ◽  
Author(s):  
L. M. Cave ◽  
P. R. Kenyon ◽  
S. T. Morris
Keyword(s):  
Body Condition ◽  
Reproductive Performance ◽  
Body Condition Score ◽  
Breeding Period ◽  
Breeding Performance ◽  
Ewe Lambs ◽  
Percentage Points ◽  
Condition Score ◽  
Ewe Lamb ◽  
Timing Of Exposure

The aims of this study were to examine the effects of exposing Romney ewe lambs (8–9 months of age) to vasectomised rams across three studies in the February–March period and to determine the influence of body condition score (CS) in two of the studies on their reproductive performance. In all studies, ewe lambs exposed to vasectomised rams had greater (P < 0.05) conception rates to the first 17 days of breeding by 6–12 percentage points. However, Studies 2 and 3 indicated that exposing ewe lambs to vasectomised rams did not increase (P > 0.05) the percentage of ewe lambs conceiving over a 34-day breeding period, nor did it increase the number of fetuses per ewe lamb presented for breeding. The results of Study 1 suggest that there is a limit to how early in the year ewe lambs can be exposed to vasectomised rams. In Study 2, a greater (P < 0.05) percentage of Teased CS 2.0 or 2.5+ ewe lambs conceived during the first 17 days of breeding than those which were Unteased. This effect was not observed (P > 0.05) in CS 1.5 ewe lambs. In Study 3, a greater (P < 0.05) percentage of CS 2.5+ ewe lambs conceived over the 34-day breeding period than ewe lambs of lower CS. In Studies 2 and 3, ewe lambs with a CS of 2.5+ had a greater (P < 0.05) number of fetuses per ewe lamb presented for breeding than CS 1.5 ewe lambs. In conclusion, exposing ewe lambs to vasectomised rams in the late February or March period increased the proportion of ewe lambs successfully bred in the first 17 days of breeding. Further achieving higher CS and heavier liveweights of ewe lambs at breeding should result in improved reproductive performance.

Reproductive performance of ewe lambs: genetic correlation with weaning weight and subsequent reproductive performance

1976 ◽  
Vol 16 (80) ◽  
pp. 321 ◽  
Author(s):  
R Barlow ◽  
CJ Hodges
Keyword(s):  
Genetic Correlation ◽  
Reproductive Performance ◽  
Agricultural Research ◽  
Reproductive Rate ◽  
Research Station ◽  
Weaning Weight ◽  
Net Reproductive Rate ◽  
Ewe Lambs ◽  
Ewe Lamb ◽  
Selection For

The reproductive performance of Merino ewe lambs was examined in flocks with different selection histories for growth to weaning and net reproductive rate. These ewes were drawn from selection flocks maintained at the Agricultural Research Station, Trangie. There was evidence of a positive genetic correlation between weaning weight and reproductive performance of ewe lambs. Selection for weaning weight had a significant effect on the percentage of ewes lambing (P < 0.05). This appeared to be a function of a higher level of fertility (P <0.05) and a higher proportion of ewes mating (n.s.). The proportion of ewes apparently in oestrus during a 39 day teasing period, prior to joining, was significantly influenced by selection for weaning weight (P < 0.05). Simultaneous selection for increased net reproductive rate, weaning weight and clean fleece weight did not result in higher ewe lamb performance than that achieved by selection for increased weaning weight alone. No conclusion could be drawn from these data about the correlation between net reproductive rate and reproductive performance of ewe lambs.

scholarly journals Toxoplasma gondii is not an important contributor to poor reproductive performance of primiparous ewes from southern Australia: a prospective cohort study

2021 ◽  
Author(s):  
Thomas Clune ◽  
Amy Lockwood ◽  
Serina Hancock ◽  
Andrew Thompson ◽  
Mieghan Bruce ◽  
...  
Keyword(s):  
Cohort Study ◽  
Toxoplasma Gondii ◽  
Prospective Cohort Study ◽  
Reproductive Performance ◽  
Prospective Cohort ◽  
Geographical Area ◽  
Tissue Samples ◽  
Important Contributor ◽  
Reproductive Losses ◽  
The Impact

Abstract Background Toxoplasma gondii causes reproductive losses in sheep worldwide, including Australia. The reproductive performance of primiparous ewes is typically lower than for mature multiparous ewes, and younger ewes are more likely to be immunologically naïve and therefore more susceptible to reproductive disease if T. gondii infection occurs during pregnancy. The aim of this study was to assess the impact of infection with T. gondii on the reproductive performance of primiparous ewes in southern Australia using a prospective cohort study. This will inform the need for targeted control strategies for T. gondii in Australian sheep. Results Toxoplasma gondii seropositivity using indirect ELISA was detected at 16/28 farms located across southern Australia. Apparent seroprevalence was lower in primiparous ewes (1.1%, 95% confidence interval (CI) 0.6, 1.8) compared to mature multiparous ewes (8.1%, 95% CI 6.0, 10.5; P < 0.001). Toxoplasma gondii seroconversion during the gestation and lambing period was confirmed for 11/1097 (1.0%, 95% CI 0.5, 1.7) of pregnant primiparous ewes that failed to raise a lamb, and 1/161 (0.6%, 95% CI 0.1, 2.9) primiparous ewes with confirmed abortion. Toxoplasma gondii was not detected using qPCR in tissue samples from aborted or stillborn lambs (n = 35) from a subset of six farms. Conclusions Low seroprevalence and low incidence of seroconversion during gestation suggests that toxoplasmosis was not an important contributor to reproductive losses in primiparous ewes on farms located over a wide geographical area in southern Australia.

Comparison of ovarian oestradiol and progesterone secretion, in vitro, between ewe lambs and ewes

2005 ◽  
Vol 2005 ◽  
pp. 149-149
Author(s):  
M. A. Younes ◽  
N. F. G. Beck ◽  
M. T. Rose ◽  
B. Davies
Keyword(s):  
Reproductive Performance ◽  
Steroid Hormone ◽  
Corpora Lutea ◽  
Ovarian Hormone ◽  
Hormone Production ◽  
Previous Evidence ◽  
Ewe Lambs ◽  
Progesterone Secretion ◽  
Ewe Lamb

Reproductive performance of ewe lambs is lower than that of adult ewes (Quirke 1979). This is mainly the result of preimplantation losses, which can exceed 50% of fertilised eggs. Previous evidence from this laboratory suggests that these losses may be associated with abnormal ovarian hormone production (Davies and Beck 1993). Khan (1999) demonstrated that blood progesterone levels during the oestrous cycle and pregnancy were lower in ewe lambs than in ewes. Furthermore, both progesterone and oestradiol concentrations were lower in ewe lambs, than in ewes, following gonadotrophin stimulation (Khan, Beck and Khalid 1999). These results suggest that ewe lamb corpora lutea and follicles secrete less progesterone and oestradiol, respectively, than those of ewes. The aim of this study was to determine whether there is a difference in vitro steroid hormone production by corpora lutea and follicles, from ewe lambs and ewes.

A comparison of ovulation rate and late embryonic mortality in ewe lambs and ewes and the rôle of late embryo loss in ewe lamb subfertility

1996 ◽  
Vol 62 (1) ◽  
pp. 79-83 ◽  
Author(s):  
N. F. G. Beck ◽  
M. C. G. Davies ◽  
B. Davies
Keyword(s):  
Reproductive Performance ◽  
Significant Contribution ◽  
Reproductive Function ◽  
Embryonic Mortality ◽  
Ovulation Rate ◽  
Embryo Survival ◽  
Ewe Lambs ◽  
Ewe Lamb ◽  
Late Embryo

AbstractAn investigation was conducted to compare late embryonic losses in ewe lambs and ewes and to determine the effect of inducing embryonic mortality on day 15 of pregnancy on reproductive function in ewe lambs. Ovulation rate and embryo survival were determined, at 15 and 30 days after mating, in a total of 83 ewe lambs and 67 ewes. Ovulation rate was lower, at spontaneous oestrus, in ewe lambs (1·07) than in ewes (1·25; P < 0·05). There was no difference in embryo survival at day 15, as 79% of ewe lambs and 80% of ewes contained expanded conceptuses. However, embryo survival was lower in ewe lambs (69%) than ewes (88%) at day 30 (P < 0·05). Embryonic mortality was induced in an additional 18 ewe lambs with an intrauterine injection of colchicine on day 15 post mating. Four of these animals had normal length oestrous cycles, six had inter-oestrus intervals ranging from 22 to 35 days and eight did not return to oestrus. Overall, the results of this study demonstrate that low ovulation rate and late embryonic losses make a significant contribution to subfertility in ewe lambs. Moreover, conceptus death is associated with luteal persistence, which may reduce reproductive performance by preventing remating.

Proportion of rams and the condition of ewe lambs at joining influences their breeding performance

2010 ◽  
Vol 50 (6) ◽  
pp. 454 ◽  
Author(s):  
P. R. Kenyon ◽  
S. T. Morris ◽  
D. M. West
Keyword(s):  
Reproductive Performance ◽  
Pregnancy Rates ◽  
Breeding Period ◽  
Breeding Performance ◽  
Ewe Lambs ◽  
Condition Score ◽  
Ewe Lamb ◽  
In Pregnancy

The aim of the present study was to examine the effects of ram : ewe lamb ratio and condition score on the reproductive performance of ewe lambs. In the 2007 study, ewe lambs were bred with rams, at ram : ewe lamb ratios of 1 : 30, 1 : 50, 1 : 75 or 1 : 100. In the 2008 study, ewe lambs were bred at ratios of 1 : 31, 1 : 50, 1 : 75 or 1 : 100. Ewe lambs were bred over two 17-day periods. In both studies, ewe lambs bred in the first 17 days of breeding only were heavier (P < 0.05) than those bred in the second 17-day period only, and those ewe lambs diagnosed as twin-bearing were heavier (P < 0.05) than their single-bearing counterparts. Ewe lambs with a condition score of 2.5 or greater were more likely (P < 0.05) to be bred, and be pregnant, in the first 17 days of breeding than those of condition score 1.5 or 2.0. Over the entire 34-day breeding period, ewe lambs with a condition score of 2.5 or greater had higher (P < 0.05) pregnancy rates than those with a condition score of 2.0, which in turn had higher rates than those of 1.5. In the 2007 study, after 34 days of breeding, there were no differences (P > 0.05) in pregnancy rates among the different ram : ewe lamb ratios. While in the 2008 study, pregnancy rates after 34 days were greater (P < 0.05) in the 1 : 50 compared with both the 1 : 75 and 1 : 100 treatments. Pregnancy rates of 1 : 31 ewe lambs were greater (P < 0.05) than those of 1 : 75 ewe lambs. In the 2007 study, pregnancy rates of ewe lambs to the first 17 days of breeding were greater (P < 0.05) for those bred at a ratio of 1 : 75 than for those bred at 1 : 50, and tended to be greater (P = 0.08) than for those bred at 1 : 100. In addition, those bred at a ratio of 1 : 30 tended to have higher pregnancy rates (P = 0.07) than those bred at 1 : 50. While in the 2008 study, pregnancy rates to the first 17 days of breeding were greatest (P < 0.05) in the 1 : 31 and 1 : 50 treatments groups. In conclusion, the results of the present study indicate that achieving greater liveweights and higher condition scores of ewe lambs at breeding will increase the proportion pregnant, especially early in the breeding period. The data also suggest, in combination with the results of previous research, that farmers should consider utilising ram : ewe lamb ratios lower than 1 : 100, although further studies are warranted.

scholarly journals Prospective cohort study of mortality in very low birthweight infants in a single centre in the Eastern Cape province, South Africa

2021 ◽  
Vol 5 (1) ◽  
pp. e000918
Author(s):  
Isabel A Michaelis ◽  
Ingeborg Krägeloh-Mann ◽  
Ncomeka Manyisane ◽  
Mikateko C Mazinu ◽  
Esme R Jordaan
Keyword(s):  
South Africa ◽  
Cohort Study ◽  
Birth Weight ◽  
Mortality Rate ◽  
Prospective Cohort Study ◽  
Prospective Cohort ◽  
Low Birthweight ◽  
Eastern Cape Province ◽  
Eastern Cape ◽  
Overall Mortality

BackgroundNeonatal mortality is a major contributor worldwide to the number of deaths in children under 5 years of age. The primary objective of this study was to assess the overall mortality rate of babies with a birth weight equal or below 1500 g in a neonatal unit at a tertiary hospital in the Eastern Cape Province, South Africa. Furthermore, different maternal-related and infant-related factors for higher mortality were analysed.MethodsThis is a prospective cohort study which included infants admitted to the neonatal wards of the hospital within their first 24 hours of life and with a birth weight equal to or below 1500 g. Mothers who consented answered a questionnaire to identify factors for mortality.Results173 very low birth weight (VLBW) infants were recruited in the neonatal department between November 2017 and December 2018, of whom 55 died (overall mortality rate 32.0%). Twenty-three of the 44 infants (53,5%) with a birth weight below 1000 g died during the admission. One hundred and sixty-one mothers completed the questionnaire and 45 of their babies died.Main factors associated with mortality were lower gestational age and lower birth weight. Need for ventilator support and sepsis were associated with higher mortality, as were maternal factors such as HIV infection and age below 20 years.ConclusionThis prospective study looked at survival of VLBW babies in an underprivileged part of the Eastern Cape of South Africa. Compared with other public urban hospitals in the country, the survival rate remains unacceptably low. Further research is required to find the associated causes and appropriate ways to address these.

scholarly journals Live Weight Changes and Their Relationship with the Ovarian Status of Maiden Fat-Tailed Barbarine Ewes

2010 ◽  
Vol 15 ◽  
pp. 41
Author(s):  
Imēne Ben Salem ◽  
Mourad Rekik ◽  
Mohammed Ben Hamouda ◽  
Narjess Lassoued
Keyword(s):  
Weight Loss ◽  
Reproductive Performance ◽  
Ovarian Function ◽  
Live Weight ◽  
Weight Changes ◽  
Ewe Lambs ◽  
Ovarian Status ◽  
Weight Variation ◽  
Igf I ◽  
Semi Arid

The current study assessed the effect of the pattern of live weight change on the ovarian function of maiden Barbarine ewes at approximately 1 year of age. For this purpose, a total of 171 weaned ewe lambs (mean live weight  ± s.d. 34.7±3.07 kg and mean age ± SD 196±10 days at weaning) were selected for the experiment. Adjustment of live weight variation  was used. Based on the slope of the curve, animals were grouped into three classes LWCI (n=46),  LWCII (n=91) and LWCIII (n=34) with live weight loss being highest in LWCI and lowest in LWCIII.  Following laparoscopy at 13 months of age, the proportion of ewe lambs found cycling in LWCIII  (85.3%) was higher in comparison to animals in LWCI (43.4%; P<0.001) and tended to be superior to those in LWCII (61.5%; P<0.05). Following synchronisation with progestagen of the females found cycling, levels of plasma IGF-I concentrations between 6 and 42 hrs after removal of sponges were not significantly different between the three classes of live weight, and respectively averaged 94.2, 90.8 and 89.8 µg/l for LWCI, LWCII and LWCIII females. Levels of estradiol were also not significantly different between the three groups (0.73, 0.70 and 0.67 pg/ml for LWCI, LWCII and LWCIII ewe lambs, respectively). It was concluded that, in low input systems of semi-arid and arid Tunisia, mating ewe lambs at the approximate age of 1 year is likely to lead to depressed reproductive performance particularly when the summer live weight-loss is elevated. 

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