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Munn AL, Swinbourne A, Brougham BJ, van Wettere W, Weaver AC. The effects of maternal calcium status during late gestation on lamb growth and survival in twin-bearing Merino ewes grazing pasture. Aust Vet J 2024; 102:249-255. [PMID: 38369317 DOI: 10.1111/avj.13321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/21/2024] [Indexed: 02/20/2024]
Abstract
Our project aimed to investigate whether low maternal calcium status during late gestation decreased weight, growth and survival of lambs born to twin-bearing Merino ewes grazing pasture. On day 130 of gestation, approximately a 10 mL blood sample was collected from 108 twin-bearing Merino ewes. Blood pH and calcium ion concentration were measured in whole blood and serum was analysed for calcium, magnesium, phosphate, beta hydroxy butyrate, non-esterified fatty acids and cholesterol. Six to 18 h after birth and at 49 days of age, lamb live weight was recorded. Ewe serum calcium level at day 130 of gestation were divided into tertiles (1.58-2.13, 2.14-2.30, and 2.31-2.99 mmol/L) with ewes classified as either Low, Med or High (n = 36 per group). A general linear mixed model was used to analyse the data. Survival to 1, 2, 3 and 7 days of age was lower for lambs born to ewes in the Low calcium group compared with those born in the Med and High calcium groups (P < 0.05). At day 49 of age, lamb survival tended to be lower for lambs in the Low (73.6%) compared with Med (86.8%) and High (85.3%) calcium groups (P < 0.1). There were no differences in lamb body weight (P > 0.05). Calcium levels of ewes in the Low calcium group were, on average, indicative of subclinical hypocalcaemia, with this group of ewes also having the lowest lamb survival rate, suggesting that maternal subclinical hypocalcaemia reduces lamb survival. Further studies, particularly on improving maternal calcium levels, are warranted.
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Affiliation(s)
- A L Munn
- Davies Livestock Research Centre, The University of Adelaide, Roseworthy, South Australia, Australia
| | - Amf Swinbourne
- Turretfield Research Centre, South Australian Research and Development Institute, Rosedale, South Australia, Australia
| | - B-J Brougham
- Davies Livestock Research Centre, The University of Adelaide, Roseworthy, South Australia, Australia
| | - Whej van Wettere
- Davies Livestock Research Centre, The University of Adelaide, Roseworthy, South Australia, Australia
| | - A C Weaver
- Turretfield Research Centre, South Australian Research and Development Institute, Rosedale, South Australia, Australia
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Flay KJ, Chen AS, Yang DA, Kenyon PR, Ridler AL. Identification of risk factors for ewe mortality during the pregnancy and lambing period in extensively managed flocks. BMC Vet Res 2023; 19:257. [PMID: 38053208 DOI: 10.1186/s12917-023-03822-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 11/23/2023] [Indexed: 12/07/2023] Open
Abstract
BACKGROUND Ewe mortality during pregnancy and lambing is an issue for sheep producers globally, resulting in reduced productivity and profitability, compromised ewe welfare, and poor consumer perception. Despite these negative consequences, there was little investigation into factors associated with ewe death during this time. Therefore, this study aimed to assess associations between ewe body condition score (BCS), weight, reproductive parameters, and risk of mortality during pregnancy and lambing. METHODS Four cohorts from three commercial New Zealand farms participated, with 13,142 ewe lambs enrolled and followed over time. Data were collected for five consecutive lambings. Visits aligned with key on-farm management times, specifically: prior to breeding, at pregnancy diagnosis (PD), prior to lambing (set-stocking), and, at weaning of their lambs. At each visit, ewes were weighed, BCS assessed and reproductive status was recorded when relevant (litter size at PD and lactation status after lambing). Ewes that died or were culled were recorded, and any ewes that were absent from consecutive visits were presumed dead. Logistic regressions were developed to assess the relationship between weight and BCS at each visit, PD result (single or multiple-bearing) and lactation status (wet or dry) in each year, and, risk of mortality during the pregnancy and lambing period in each year. RESULTS In the PD to weaning period, mortality incidence ranged from 6.3 to 6.9% for two-tooth (18-months-old at breeding) to mixed-age (54-months-old at breeding) ewes. For ewe lambs (7 to 8-months-old at breeding), mortality was 7.3% from set-stocking to weaning. Heavier ewe lambs at PD were less likely to die during lambing (OR: 0.978, p = 0.013), as were those with greater set-stocking BCS. In subsequent years, BCS was a predictor of ewe death, with odds of mortality greatest for ewes < BCS 2.5. Additionally, for poorer BCS ewes, increasing weight reduced risk of mortality, but there was no impact of increasing weight in greater BCS ewes. CONCLUSIONS This study identified risk factors associated with ewe mortality during the pregnancy and lambing period. Flock owners can use these to either cull at-risk ewes or proactively intervene to reduce likelihood of mortality, thereby improving flock productivity, profitability and welfare.
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Affiliation(s)
- K J Flay
- Department of Veterinary Clinical Sciences, City University of Hong Kong, 31 To Yuen St, Kowloon, Hong Kong SAR, China.
| | - A S Chen
- College of Veterinary Medicine, Nanjing Agricultural University, 1 Weigang, Nanjing, 210095, China
| | - D A Yang
- College of Veterinary Medicine, Nanjing Agricultural University, 1 Weigang, Nanjing, 210095, China
| | - P R Kenyon
- School of Agriculture and Environment, Massey University, Private Bag 11-222, Palmerston North, New Zealand
| | - A L Ridler
- School of Veterinary Science, Massey University, Private Bag 11-222, Palmerston North, New Zealand
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Zhang H, Yang P, Liu C, Ma Y, Han Y, Zeng Y, Huang Y, Zhao Y, Zhao Z, He X, E G. Novel Heredity Basis of the Four-Horn Phenotype in Sheep Using Genome-Wide Sequence Data. Animals (Basel) 2023; 13:3166. [PMID: 37893889 PMCID: PMC10603714 DOI: 10.3390/ani13203166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 10/08/2023] [Accepted: 10/10/2023] [Indexed: 10/29/2023] Open
Abstract
Horns are an important breeding trait for sheep. However, no widely recognized viewpoint on the regulatory genes and mechanisms of horns is available, and the genetic basis of the four-horn phenotype (FHP) is unclear. This work conducted a genome-wide association study with 100 sheep genomes from multiple breeds to investigate the genetic basis of the FHP. The results revealed three significant associations (corrected as p < 1.64 × 10-8) of the InDels (CHR2: g.133,742,709delA, g.133,743,215insC, and g.133,743,940delT) for FHP in the intergenic sequence (IGS) between the MTX2 and the LOC105609047 of CHR2. Moreover, 14 significant associations (corrected as p < 1.42 × 10-9) of SNPs with the FHP phenotype were identified in CHR2 and CHR16, including five (e.g., CHR16: g.40,351,378G > A and g.40,352,577G > A) located in the intron of the ADAMTS12 gene, eight (e.g., CHR2: g.133,727,513C > T and g.133,732,145T > G) in the IGS between MTX2 and LOC105609047, and only one (CHR2: g.133,930,761A > G) in the IGS between HOXD1 and MTX2. Obvious divergence was also observed in genotype patterns between the FHP and others (two horns and hornless) in the HOXD1 and ADAMTS12 gene regions. An extremely significant linkage also occurred between Loci I and Loci II within 100 individuals (LD = -156.02186, p < 0.00001). In summary, our study indicated that the genomic sequences from CHR2 and CHR16 contributed to the FHP in sheep, specifically the key candidate genes HOXD1 and ADAMTS12. These results improved our understanding of the Mendelian genetic basis of the FHP in sheep.
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Affiliation(s)
- Haoyuan Zhang
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - Pu Yang
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - Chengli Liu
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - Yuehui Ma
- Institute of Animal Husbandry and Veterinary Medicine, Chinese Academy of Agricultural Sciences, Beijing 100097, China
| | - Yanguo Han
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - Yan Zeng
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - Yongfu Huang
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - Yongju Zhao
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - Zhongquan Zhao
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - Xiaohong He
- Institute of Animal Husbandry and Veterinary Medicine, Chinese Academy of Agricultural Sciences, Beijing 100097, China
| | - Guangxin E
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
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Clune T, Bruce M, Glanville E, Campbell AJD, Lockwood A, Hancock S, Thompson AN, Beetson S, Brookes D, Trengove C, O'Handley R, Jacobson C. Seropositivity to
Campylobacter
and association with abortion and lamb mortality in maiden ewes from Western Australia, South Australia and Victoria. Aust Vet J 2022; 100:397-406. [PMID: 35665919 PMCID: PMC9544749 DOI: 10.1111/avj.13173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/27/2022] [Accepted: 05/01/2022] [Indexed: 11/29/2022]
Abstract
This case‐control study investigated associations between Campylobacter fetus or Campylobacter jejuni titre and reproductive outcomes in 22 flocks of Merino and non‐Merino maiden ewes aged 1–2 years old. Campylobacter titres were also determined for multiparous ewes aged 3 years or older on the same farms. C. fetus ‘positivity’ (titre ≥1:80) was detected for 12% (57/462; 95% confidence interval [95% CI] 9.6 to 15.6) of maiden ewes and 31% (65/210; 95% CI 25.0 to 37.4) of mature ewes. The odds for failing to rear a lamb in C. fetus‐‘exposed’ maiden ewes (titre ≥1:10) was 2.01 times that of seronegative ewes (95% CI 1.09 to 3.77; P = 0.027), but there was no association between C. fetus‐‘positivity’ (titre ≥1:80) and failure to rise (OR 1.69; 95% CI 0.77 to 3.76; P = 0.191). C. fetus abortions were confirmed with microbial culture in one maiden ewe flock. In this flock, C. fetus titres fluctuated and often waned by lamb marking, highlighting the value of necropsies during abortion investigations. C. jejuni‐‘positivity’ (titre ≥1:80) was detected for 44% (204/462; 95% CI 39.7 to 48.7) maiden ewes, but odds of failing to rear were decreased for C. jejuni‐‘positive’ ewes (OR 0.52; 95% CI 0.32 to 0.83; P = 0.007). The association between Campylobacter serology and the reproductive outcome was inconsistent in these flocks. Serology should be considered in the context of other risk factors and used in conjunction with other strategies to investigate the impact of Campylobacter exposure on ewe reproductive performance such as monitoring for abortions and lamb necropsies to determine aetiological diagnosis, and vaccination trials.
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Affiliation(s)
- T Clune
- Centre for Animal Production and Health, Food Futures Institute Murdoch University South Street Murdoch Western Australia 6150 Australia
| | - M Bruce
- Centre for Biosecurity and One Health, Harry Butler Institute Murdoch University South Street Murdoch Western Australia 6150 Australia
| | - E Glanville
- Mackinnon Project, Faculty of Veterinary and Agricultural Sciences University of Melbourne Werribee Victoria 3030 Australia
| | - AJD Campbell
- Nossal Institute for Global Health, Melbourne School of Population and Global Health University of Melbourne Melbourne Victoria 3010 Australia
| | - A Lockwood
- Centre for Animal Production and Health, Food Futures Institute Murdoch University South Street Murdoch Western Australia 6150 Australia
| | - S Hancock
- Centre for Animal Production and Health, Food Futures Institute Murdoch University South Street Murdoch Western Australia 6150 Australia
| | - AN Thompson
- Centre for Animal Production and Health, Food Futures Institute Murdoch University South Street Murdoch Western Australia 6150 Australia
| | - S Beetson
- Centre for Animal Production and Health, Food Futures Institute Murdoch University South Street Murdoch Western Australia 6150 Australia
| | - D Brookes
- Mackinnon Project, Faculty of Veterinary and Agricultural Sciences University of Melbourne Werribee Victoria 3030 Australia
| | - C Trengove
- School of Animal and Veterinary Sciences University of Adelaide Roseworthy South Australia 5371 Australia
| | - R O'Handley
- School of Animal and Veterinary Sciences University of Adelaide Roseworthy South Australia 5371 Australia
| | - C Jacobson
- Centre for Animal Production and Health, Food Futures Institute Murdoch University South Street Murdoch Western Australia 6150 Australia
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Clune T, Lockwood A, Hancock S, Thompson AN, Bruce M, Beetson S, Campbell AJ, Glanville E, Brookes D, Trengove C, O’Handley R, Jacobson C. Toxoplasma gondii is not an important contributor to poor reproductive performance of primiparous ewes from southern Australia: a prospective cohort study. BMC Vet Res 2022; 18:109. [PMID: 35305646 PMCID: PMC8933891 DOI: 10.1186/s12917-022-03211-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 03/10/2022] [Indexed: 11/15/2022] Open
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 seropositivity to T. gondii 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 mid-pregnancy abortion. Conclusions Low frequency of detection of T. gondii seroconversion during gestation and low frequency of seropositivity to T. gondii 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. Supplementary Information The online version contains supplementary material available at 10.1186/s12917-022-03211-w.
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Clune T, Lockwood A, Hancock S, Thompson AN, Beetson S, Campbell AJD, Glanville E, Brookes D, Trengove C, O'Handley R, Kearney G, Jacobson C. Abortion and Lamb Mortality between Pregnancy Scanning and Lamb Marking for Maiden Ewes in Southern Australia. Animals (Basel) 2021; 12:10. [PMID: 35011116 DOI: 10.3390/ani12010010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 11/24/2021] [Accepted: 11/29/2021] [Indexed: 12/01/2022] Open
Abstract
Simple Summary The reproductive efficiency of ewes in their first breeding season (maiden ewes) can be inconsistent and disappointing. The frequency of abortion and its relative contribution to lamb losses in maiden ewe flocks in Australia has not been well studied. This study measured abortion and lamb mortality occurring between pregnancy diagnosis (scanning) and lamb marking in 30 flocks of maiden ewes on Australian sheep farms. The study included flocks of ewe lambs that had lambed for the first time at approximately one-year-old (n = 19) and two-tooth ewes that had lambed for the first time at two-years-old (n = 11). Abortion was detected in 14/19 flocks of ewe lambs and 6/11 flocks of two-tooth ewes using repeated scans. On average 5.7% of ewe lambs and 0.9% of two-tooth ewes aborted; however, abortion rates between flocks ranged from 0–50% for ewe lambs and 0–4.4% for two-tooth ewes. Lamb mortality from birth to marking represented the greatest contributor to overall lamb mortality occurring after pregnancy scanning but abortions were an important contributor to the overall losses in some ewe lamb flocks. This study highlights the variability in reproductive performance for maiden ewes and indicates that addressing losses due to abortion may improve reproductive performance in some ewe lamb flocks. Abstract 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.
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