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Redfearn A, Janodet E, McNally J, Brewer H, Doyle E, Doyle R, Schmoelzl S. Postnatal maternal behaviour expression depends on lambing difficulty in Merino ewes. Theriogenology 2023; 196:31-36. [PMID: 36379143 DOI: 10.1016/j.theriogenology.2022.11.001] [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: 03/21/2022] [Revised: 11/01/2022] [Accepted: 11/02/2022] [Indexed: 11/06/2022]
Abstract
Dystocia, a prolonged or non-progressive birth event, is the main contributor to lamb mortality in Australia and across the world. Dystocia can cause neonatal hypoxia, central nervous system (CNS) damage leading to increased risk of starvation, exposure and mismothering, and death. These prolonged birth events can also cause fatigue, injury and death in the ewe. Dystocia may interrupt the expression of maternal behaviour and the strength of the ewe-lamb bond, and consequently lamb survival. This study focused on the effect of dystocia on ewe behaviour in the 2 h post-lambing. A total of 18 ewes were chosen for continuous behaviour annotation and analysis (dystocic (n = 9) and eutocic (n = 9)) based on the quality of video recordings, length of stage 2 parturition and classification by a single experienced observer. Dystocic ewes showed significantly lower expression of maternal behaviours and a significantly greater expression of avoidance behaviours compared to eutocic ewes. Additionally, dystocic ewes performed fewer behaviours in total compared to eutocic ewes. Dystocia can significantly affect the quality and quantity of ewe maternal behaviour expression, leading to increased avoidance of the lamb, increased risk of maternal disinterest, and increased risk of death for the lamb. If dystocic events can be identified quickly and accurately, measures can be taken to ensure the ewe and lamb recover successfully.
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Affiliation(s)
- Amellia Redfearn
- CSIRO Chiswick, FD McMaster Laboratory, Armidale, NSW, 2350, Australia; University of New England, School of Environmental and Rural Science, Armidale, NSW, 2350, Australia
| | - Estelle Janodet
- CSIRO Chiswick, FD McMaster Laboratory, Armidale, NSW, 2350, Australia; Bordeaux Sciences Agro, University of Bordeaux, 33175, Gradignan Cedex, France; GenPhySE, Animal Genetics and Breeding Unit, Université de Toulouse, INRAE, 31326, Castanet-Tolosan, France
| | - Jody McNally
- CSIRO Chiswick, FD McMaster Laboratory, Armidale, NSW, 2350, Australia
| | - Heather Brewer
- CSIRO Chiswick, FD McMaster Laboratory, Armidale, NSW, 2350, Australia
| | - Emma Doyle
- University of New England, School of Environmental and Rural Science, Armidale, NSW, 2350, Australia
| | - Rebecca Doyle
- University of Melbourne, Melbourne, VIC, 3010, Australia; Jeanne Marchig International Centre for Animal Welfare Education, The University of Edinburgh, Midlothian, EH259RG, Scotland, UK
| | - Sabine Schmoelzl
- CSIRO Chiswick, FD McMaster Laboratory, Armidale, NSW, 2350, Australia; University of New England, School of Environmental and Rural Science, Armidale, NSW, 2350, Australia.
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2
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Clune T, Lockwood A, Hancock S, Thompson AN, Beetson S, Bruce M, Campbell AJ, Glanville E, Brookes D, Trengove C, O'Handley R, Jacobson C. Seropositivity to Coxiella burnetii in primiparous and multiparous ewes from southern Australia: A cross-sectional study. Comp Immunol Microbiol Infect Dis 2021; 80:101727. [PMID: 34875542 DOI: 10.1016/j.cimid.2021.101727] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 11/26/2022]
Abstract
The role of infectious diseases including coxiellosis in causing poorer reproductive performance of primiparous ewes are not well studied. The aims of this study were to determine if natural exposure to Coxiella burnetii is widespread in breeding ewes and whether seropositivity is associated with poor reproductive performance of primiparous ewes. Seropositivity to Coxiella burnetii was 0.08% (CI95% 0.01, 0.36) in primiparous ewes and 0.36% (CI95% 0.07, 1.14) in mature ewes. Coxiella burnetii was not detected in aborted or stillborn lambs using qPCR. These findings suggest C. burnetii infection was unlikely to be an important contributor to abortion and perinatal mortalities observed for primiparous ewe flocks, and exposure to C. burnetii was not widespread in ewes on farms located over wide geographical region of southern Australia. Whilst ewes on these farms were not an important reservoir for C. burnetii, sporadic zoonotic transmission from sheep is reported and has public health implications.
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Affiliation(s)
- Tom Clune
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, South Street, Murdoch, Western Australia 6150, Australia
| | - Amy Lockwood
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, South Street, Murdoch, Western Australia 6150, Australia
| | - Serina Hancock
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, South Street, Murdoch, Western Australia 6150, Australia
| | - Andrew N Thompson
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, South Street, Murdoch, Western Australia 6150, Australia
| | - Sue Beetson
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, South Street, Murdoch, Western Australia 6150, Australia
| | - Mieghan Bruce
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, South Street, Murdoch, Western Australia 6150, Australia; Centre for Biosecurity and One Health, Harry Butler Institute, Murdoch University, South Street, Murdoch, Western Australia 6150, Australia
| | - Angus J Campbell
- Nossal Institute for Global Health, Melbourne School of Population and Global Health, University of Melbourne, Victoria 3010, Australia; Mackinnon Project, Faculty of Veterinary & Agricultural Sciences, University of Melbourne, Werribee, Victoria 3030, Australia
| | - Elsa Glanville
- Mackinnon Project, Faculty of Veterinary & Agricultural Sciences, University of Melbourne, Werribee, Victoria 3030, Australia
| | - Daniel Brookes
- Mackinnon Project, Faculty of Veterinary & Agricultural Sciences, University of Melbourne, Werribee, Victoria 3030, Australia
| | - Colin Trengove
- School of Animal and Veterinary Science, Adelaide University, Roseworthy, South Australia 5371, Australia
| | - Ryan O'Handley
- School of Animal and Veterinary Science, Adelaide University, Roseworthy, South Australia 5371, Australia
| | - Caroline Jacobson
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, South Street, Murdoch, Western Australia 6150, Australia.
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3
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Clune T, Lockwood A, Hancock S, Bruce M, Thompson AN, Beetson S, Campbell AJ, Glanville E, Brookes D, Trengove C, O'Handley R, Jacobson C. Neospora caninum is not an important contributor to poor reproductive performance of primiparous ewes from southern Australia: evidence from a cross-sectional study. Parasitol Res 2021; 120:3875-3882. [PMID: 34599357 DOI: 10.1007/s00436-021-07328-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/22/2021] [Indexed: 11/29/2022]
Abstract
Neospora caninum has been implicated as a sporadic cause of abortion and perinatal deaths in sheep flocks globally. However, its significance as a reproductive pathogen for sheep in Australia remains unknown. The aims of this study were to (i) determine the seroprevalence of N. caninum in Australian breeding ewes and (ii) examine if natural exposure to N. caninum is associated with poor reproductive performance of primiparous ewes in southern Australia. Thirty flocks of primiparous ewes (aged 1-2 years old at lambing) from 28 farms in three states (Western Australia, South Australia and Victoria) were monitored between mating and lamb marking. Blood samples were also collected from multiparous mature ewes (aged 3 years or older) at each farm. Seroprevalence for anti-N. caninum IgG using indirect ELISA was determined for a subset of primiparous ewes that were predominantly determined to be pregnant and subsequently failed to rear a lamb (n = 1279) and randomly selected mature multiparous ewes with unknown reproductive status (n = 558). Neopsora caninum apparent seroprevalence was 0.16% (95% confidence interval 0.03%, 0.5%) in primiparous ewes, with seropositivity identified in two ewes from farms located in South Australia and Victoria. There was no evidence of seropositivity in mature ewes with apparent seroprevalence 0% (0%, 0.45%). These findings suggest that N. caninum infection was not widespread in primiparous ewes or mature multiparous ewes on these farms, and exposure to N. caninum infection was unlikely to explain abortion and perinatal mortalities observed for primiparous ewes.
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Affiliation(s)
- Thomas Clune
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia
| | - Amy Lockwood
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia
| | - Serina Hancock
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia
| | - Mieghan Bruce
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia
| | - Andrew N Thompson
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia
| | - Sue Beetson
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia
| | - Angus J Campbell
- Nossal Institute for Global Health, Melbourne School of Population and Global Health, University of Melbourne, Victoria, 3010, Australia.,Mackinnon Project, Faculty of Veterinary & Agricultural Sciences, University of Melbourne, Werribee, Victoria, 3030, Australia
| | - Elsa Glanville
- Mackinnon Project, Faculty of Veterinary & Agricultural Sciences, University of Melbourne, Werribee, Victoria, 3030, Australia
| | - Daniel Brookes
- Mackinnon Project, Faculty of Veterinary & Agricultural Sciences, University of Melbourne, Werribee, Victoria, 3030, Australia
| | - Colin Trengove
- School of Animal and Veterinary Science, University of Adelaide, Roseworthy, South Australia, 5371, Australia
| | - Ryan O'Handley
- School of Animal and Veterinary Science, University of Adelaide, Roseworthy, South Australia, 5371, Australia
| | - Caroline Jacobson
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia.
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4
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Bruce M, Young JM, Masters DG, Refshauge G, Thompson AN, Kenyon PR, Behrendt R, Lockwood A, Miller DW, Jacobson C. The impact of lamb and ewe mortality associated with dystocia on Australian and New Zealand sheep farms: A systematic review, meta-analysis and bio-economic model. Prev Vet Med 2021; 196:105478. [PMID: 34487918 DOI: 10.1016/j.prevetmed.2021.105478] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 07/22/2021] [Accepted: 08/31/2021] [Indexed: 10/20/2022]
Abstract
Dystocia contributes to lamb and ewe mortality in the periparturient period but impacts for extensive sheep production systems remain poorly understood. Here we show that lamb and ewe mortality associated with dystocia has important impacts on sheep production in Australia and New Zealand, and quantify financial impacts for the Australian sheep industry. A systematic review of the literature identified 11 publications published since 1990 that reported sheep mortality due to dystocia in Australia or New Zealand. Assumptions for ewe breeding flock structure and reproductive performance were based on Australian sheep industry data. The proportion of lamb mortality attributable to dystocia (including stillbirths and perinatal deaths with evidence of hypoxic injury) pooled across all studies (pooled proportional mortality ratio) was 47 % (95 % Confidence Interval (CI): 38, 55). Pooled proportional mortality ratio for Australian studies was 53 % (95 %CI: 47, 60), and for New Zealand studies was 35 % (95 %CI: 19, 51). Pooled proportional mortality ratio was similar for lambs born to Merino and non-Merino ewes, although more data are needed to determine effects of ewe breed independent of other factors. Pooled proportional mortality ratio was higher for single lambs (59 %; 95 % CI: 55, 63) than twin (47 %; 41, 54) or triplet (49 %; 46, 52) lambs. However, the number of dystocia-associated mortalities is higher for twin-born lambs than for singles because total mortality is higher for twin-born lambs. It is estimated that approximately 7.7 million lamb deaths and 297,500 ewe deaths per year are attributable to dystocia in Australia for the national flock of 38 million breeding ewes. The whole-farm bio-economic Model of an Integrated Dryland Agricultural System (MIDAS) was used to determine the impacts of dystocia-associated ewe and lamb mortality on Australian farm profit. Dystocia is estimated to reduce Australian national farm profit by AU$780 million or $23.00 per ewe mated based on an assumed lamb sale price of AU$6.50 per kg carcass weight. These estimates do not include the costs of reduced productivity for surviving ewes and lambs, intervention, post-farmgate impacts, delayed genetic progress, or impacts on animal welfare and access into sheep meat and wool markets. Reducing dystocia through improved genetics and sheep management will improve animal welfare and farm profit.
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Affiliation(s)
- Mieghan Bruce
- Centre for Animal Production and Health, Murdoch University, 90 South Street, Murdoch, WA, 6150, Australia
| | - John M Young
- Farming Systems Analysis Service, 476 Tindale Rd, Kentdale, WA, 6333, Australia
| | - David G Masters
- School of Agriculture and Environment, M085, University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia
| | - Gordon Refshauge
- New South Wales Department of Primary Industries, Cowra Agricultural Research and Advisory Station, Cowra, NSW, 2794, Australia
| | - Andrew N Thompson
- Centre for Animal Production and Health, Murdoch University, 90 South Street, Murdoch, WA, 6150, Australia
| | - Paul R Kenyon
- International Sheep Research Centre, Massey University, Palmerston North, 4410, New Zealand
| | - Ralph Behrendt
- Agriculture Victoria Research, Department of Jobs, Precincts and Regions, Hamilton, Victoria, 3300, Australia
| | - Amy Lockwood
- Centre for Animal Production and Health, Murdoch University, 90 South Street, Murdoch, WA, 6150, Australia
| | - David W Miller
- Centre for Animal Production and Health, Murdoch University, 90 South Street, Murdoch, WA, 6150, Australia
| | - Caroline Jacobson
- Centre for Animal Production and Health, Murdoch University, 90 South Street, Murdoch, WA, 6150, Australia.
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5
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Fallah R, Kiani A, Khaldari M. Supplementing lycopene combined with corn improves circulating IgG concentration in pregnant ewes and their lambs. Trop Anim Health Prod 2021; 53:360. [PMID: 34128134 DOI: 10.1007/s11250-021-02802-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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: 02/02/2021] [Accepted: 05/31/2021] [Indexed: 11/26/2022]
Abstract
Lycopene (C40H56, a non-provitamin A carotenoid) is a lipid-soluble pigment and a natural antioxidant with immunomodulatory activities. The objective of this study was to investigate the effects of lycopene with or without corn supplementation on circulating hormones, white blood cells, immunoglobulin G (IgG) concentrations, quality of colostrum in pregnant ewes, and IgG concentrations in newborn lambs. Forty multiparous single-bearing ewes (68 ± 8.4 kg body weight, mean ± SD) were fed in four groups of CONTROL (fed a basal diet (BD)), CORN (BD + 300 g/day corn), LYCOP(BD + 100 mg/day lycopene), and LYCORN (BD + 300 g/day corn + 100 mg/day lycopene). The quantity and chemical composition of colostrum were determined. Blood samples were taken from ewes right after lambing and from lambs at 3 and 24 h of age. Results showed that corn supplementation increased (P < 0.05) udder volume, the quantity of colostrum, as well as percentage of lactose, and protein in colostrum. Corn-supplemented ewes had higher circulating glucose, prolactin, and estradiol but lower urea and progesterone than control ewes. The ratio of progesterone to estradiol (P4/E2) in the blood of pregnant ewes decreased (P < 0.05) after corn supplementation. Lycopene, irrespective of corn, increased the percentage of lymphocyte cells in pregnant ewes. Both corn and lycopene increased circulating IgG concentrations and subsequently increased the total IgG in colostrum at 6 h post-partum. Lycopene significantly elevated the circulating IgG at 24 h of age in lambs. In conclusion, lycopene along with corn supplementation additively increased concentrations of IgG in the blood of ewes and in the colostrum, which resulted in an enhancement of passive immune transfer to the newborn lambs.
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Affiliation(s)
- R Fallah
- Department of Animal Science, Faculty of Agriculture, Lorestan University, P.O.Box 465, Khorramabad, Iran
| | - Ali Kiani
- Department of Animal Science, Faculty of Agriculture, Lorestan University, P.O.Box 465, Khorramabad, Iran.
| | - M Khaldari
- Department of Animal Science, Faculty of Agriculture, Lorestan University, P.O.Box 465, Khorramabad, Iran
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6
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Clune T, Besier S, Hair S, Hancock S, Lockwood A, Thompson A, Jelocnik M, Jacobson C. Chlamydia pecorum detection in aborted and stillborn lambs from Western Australia. Vet Res 2021; 52:84. [PMID: 34116730 PMCID: PMC8196467 DOI: 10.1186/s13567-021-00950-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/18/2021] [Indexed: 12/26/2022] Open
Abstract
Lamb survival is an important welfare and productivity issue for sheep industries worldwide. Lower lamb survival has been reported for primiparous ewes, but the causes of this are not well studied. The aim of this study was to determine causes of perinatal deaths for lambs born to primiparous ewes in Western Australia, and identify if infectious diseases are implicated. Lamb mortality from birth to marking were determined for 11 primiparous ewe flocks on 10 farms in Western Australia. Lamb mortality from birth to marking averaged 14% for single-born and 26% for multiple-born lambs. Lamb necropsies (n = 298) identified starvation–mismosthering–exposure (34%), dystocia (24%) and stillbirth (15%) as the most common causes of perinatal lamb death. There was no evidence of exotic abortigenic pathogens in aborted and stillborn lambs (n = 35). Chlamydia pecorum was detected by qPCR in 15/35 aborted and stillborn lambs on 5/6 farms. Preliminary molecular characterisation of C. pecorum detected in samples from aborted and stillborn lambs (n = 8) using both Multilocus Sequence Typing and ompA genotyping indicated all strains were genetically identical to previously described pathogenic livestock strains, denoted ST23, and dissimilar to gastrointestinal strains. High frequency of detection of a pathogenic C. pecorum strains ST23 associated with ovine abortion and stillbirth on multiple farms located across a wide geographic area has not been previously reported. Chlamydia pecorum may contribute to reproductive wastage for primiparous sheep in Western Australia. Further investigation to understand C. pecorum epidemiology and impact on sheep reproduction is warranted.
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Affiliation(s)
- Tom Clune
- Centre for Animal Production and Health, Murdoch University, South Street, Murdoch, WA, 6150, Australia
| | - Shane Besier
- Department of Primary Industries and Regional Development, South Perth, WA, 6151, Australia
| | - Sam Hair
- Department of Primary Industries and Regional Development, South Perth, WA, 6151, Australia
| | - Serina Hancock
- Centre for Animal Production and Health, Murdoch University, South Street, Murdoch, WA, 6150, Australia
| | - Amy Lockwood
- Centre for Animal Production and Health, Murdoch University, South Street, Murdoch, WA, 6150, Australia
| | - Andrew Thompson
- Centre for Animal Production and Health, Murdoch University, South Street, Murdoch, WA, 6150, Australia
| | - Martina Jelocnik
- Genecology Research Centre, University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs, QLD, 4557, Australia
| | - Caroline Jacobson
- Centre for Animal Production and Health, Murdoch University, South Street, Murdoch, WA, 6150, Australia.
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7
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Pritchard CE, Williams AP, Davies P, Jones D, Smith AR. Spatial behaviour of sheep during the neonatal period: Preliminary study on the influence of shelter. Animal 2021; 15:100252. [PMID: 34090091 DOI: 10.1016/j.animal.2021.100252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/13/2021] [Accepted: 04/15/2021] [Indexed: 11/16/2022] Open
Abstract
Effective shelter has been demonstrated to reduce neonatal lamb mortality rates during periods of inclement weather. Periods of high wind speed and rainfall have been shown to influence shelter usage; however, it is not yet known how ewe factors such as breed, age and body condition score influence shelter-seeking behaviour. This study, conducted on a working upland farm in the UK, examined impact of artificial shelter on the biological and climatic factors that influence peri-parturient ewe behaviour. Pregnant ewes (n = 147) were randomly allocated between two adjacent fields which were selected for their similarity in size, topography, pasture management, orientation to the prevailing wind and available natural shelter. In one field, three additional artificial shelters were installed to increase the available shelter for ewes, this field was designated the Test field; no additional artificial shelter was provided in the second field which was used as the Control field. Individual ewes were observed every 2 h between 0800 and 1600 for 14 continuous days to monitor their location relative to shelter. Ewe breed (Aberfield and Highlander), age (2-8 years) and body condition score were considered as explanatory variables to explain flock and individual variance in shelter-seeking behaviour and the prevalence of issues which required the intervention of the shepherd, termed 'shepherding problems'. Any ewe observed with dystocia, a dead or poor vigour lamb or who exhibited mismothering behaviour was recorded as a shepherding problem. The prevalence of these shepherding problems which necessitate human intervention represents arguably the most critical limiting factor for the successful management of commercial sheep flocks in outdoor lambing systems. Overall, ewes in the Test field with access to additional artificial shelter experienced fewer shepherding problems than those in the Control field (P < 0.05). A significant breed effect was also observed, with Highlander ewes more likely to seek shelter than Aberfield ewes (P < 0.001), and experiencing significantly fewer shepherding interventions (P < 0.05). These findings demonstrate the substantial and significant benefits to animal welfare and productivity that can be achieved through the provision of shelter in commercial, upland, outdoor lambing systems in the UK.
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Affiliation(s)
- C E Pritchard
- School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2DG, UK
| | - A P Williams
- School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2DG, UK.
| | - P Davies
- Department of Livestock & One Health, Institute of Infection, University of Liverpool, Neston, CH64 7TE, UK
| | - D Jones
- Innovis Ltd., Capel Dewi, Aberystwyth SY23 3HU, UK
| | - A R Smith
- School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2DG, UK
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8
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Nel CL, Cloete SWP, Kruger ACM, Dzama K. Long term genetic selection for reproductive success affects neonatal lamb vitality across cold stress conditions. J Therm Biol 2021; 98:102908. [PMID: 34016335 DOI: 10.1016/j.jtherbio.2021.102908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/11/2021] [Accepted: 03/11/2021] [Indexed: 10/21/2022]
Abstract
Adverse weather conditions are important contributors to mortality in new-born lambs. Previous studies have shown variation between lambs in their ability to cope with circumstances of cold stress, and genetic selection could be a viable option for improving animal robustness. The Elsenburg Merino flock was divergently selected on number of lambs weaned (NLW). This resulted in divergent responses in reproduction and lamb survival. This study evaluated lamb vitality and mortality of positively selected H-Line relative to the negatively selected L-Line in response to cold stress. Traits included lamb rectal temperature (RT), surface temperature (ST), shiver score (SS), lamb vigor score (LVS), breaths per minute (BPM), mortality to three days of age (M3) and to weaning (TM). Cold stress was described by a chill index derived from daily rainfall, wind speed and ambient temperature, and represented as the mean of the one (CI), two (CI-2) or three (CI-3) days since parturition. Overall, H-Line lambs had a higher neonatal RT and were less likely to succumb than L-Line contemporaries. In a significant (P < 0.05) interaction, the predicted RT of L-Line showed a non-linear decline with increased levels of CI-2, while H-Line lambs better maintained their core temperature. M3 was also affected by a significant interaction between CI-3 and selection line, further suggesting that observed lower mortality rates in the H-Line depends on H-Line lambs' improved ability to cope with stressful environments. Long term selection for NLW in the H-Line led to improvements in both adaptations associated with lower lamb losses. The continued recording of viability traits to produce larger datasets amenable to genetic analysis is recommended, specifically for rectal temperature.
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Affiliation(s)
- Cornelius L Nel
- Department of Animal Sciences, Stellenbosch University, Stellenbosch, 7602, South Africa.
| | - Schalk W P Cloete
- Department of Animal Sciences, Stellenbosch University, Stellenbosch, 7602, South Africa.
| | - Annelie C M Kruger
- Directorate: Animal Sciences, Western Cape Department of Agriculture, Elsenburg, 7607, South Africa.
| | - Kennedy Dzama
- Department of Animal Sciences, Stellenbosch University, Stellenbosch, 7602, South Africa.
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9
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Flinn T, Kleemann DO, Swinbourne AM, Kelly JM, Weaver AC, Walker SK, Gatford KL, Kind KL, van Wettere WHEJ. Neonatal lamb mortality: major risk factors and the potential ameliorative role of melatonin. J Anim Sci Biotechnol 2020; 11:107. [PMID: 33292527 PMCID: PMC7643391 DOI: 10.1186/s40104-020-00510-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 09/07/2020] [Indexed: 12/19/2022] Open
Abstract
High incidences of pre-weaning mortality continue to limit global sheep production, constituting a major economic and welfare concern. Despite significant advances in genetics, nutrition, and management, the proportion of lamb deaths has remained stable at 15–20% over the past four decades. There is mounting evidence that melatonin can improve outcomes in compromised ovine pregnancies via enhanced uterine bloodflow and neonatal neuroprotection. This review provides an overview of the major risk factors and underlying mechanisms involved in perinatal lamb mortality and discusses the potential of melatonin treatment as a remedial strategy. Supplementing pregnant ewes with melatonin enhances uterine bloodflow and fetal oxygenation, and potentially birthweight and neonatal thermogenic capacity. Melatonin freely crosses the ovine placenta and blood-brain barrier and provides neuroprotection to the fetal lamb during periods of chronic and acute hypoxia throughout gestation, with improved behavioural outcomes in hypoxic neonates. The current literature provides strong evidence that maternal melatonin treatment improves outcomes for lambs which experience compromised in utero development or prolonged parturition, though to date this has not been investigated in livestock production systems. As such there is a clear basis for continued research into the effects of maternal melatonin supplementation during gestation on pre-weaning survival under extensive production conditions.
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Affiliation(s)
- Tom Flinn
- Davies Livestock Research Centre, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, Australia.
| | - David O Kleemann
- Turretfield Research Centre, South Australian Research and Development Institute, Rosedale, SA, Australia
| | - Alyce M Swinbourne
- Davies Livestock Research Centre, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, Australia
| | - Jennifer M Kelly
- Turretfield Research Centre, South Australian Research and Development Institute, Rosedale, SA, Australia
| | - Alice C Weaver
- Turretfield Research Centre, South Australian Research and Development Institute, Rosedale, SA, Australia
| | - Simon K Walker
- Turretfield Research Centre, South Australian Research and Development Institute, Rosedale, SA, Australia
| | - Kathryn L Gatford
- Robinson Research Institute, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Karen L Kind
- Davies Livestock Research Centre, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, Australia
| | - William H E J van Wettere
- Davies Livestock Research Centre, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, Australia
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