Research in the ABRD encompasses nutrition, fertility, breeding, health and welfare. Research activities focus on producing profitable animals and the corresponding management strategies to deliver the productivity, sustainability and product quality targets set out in Ireland’s Food Harvest 2020 vision. The ABRD uses a powerful combination of established animal science techniques, as well as cutting-edge molecular and computational biology tools, to answer relevant industry research questions. Our focus is on dairy and beef cattle and sheep. We have developed animal models that are divergent for a range of economically important traits.

Recent Submissions

  • 28. The effect of phenotypically ranking beef cattle for residual methane output on daily methane emissions, intensity and animal productivity

    Smith, Paul E.; Waters, Sinéad M.; Kenny, David A.; Kirwan, Stuart F.; Conroy, Stephen; Kelly, Alan K.; European Union; 16/RD/ERAGAS/1RUMENPREDICT-ROI2017; 818368 (Elsevier BV, 2021-04)
    Beef cattle ranked as having low residual methane output had lower emissions intensity and similar overall productive performance as their high emissions ranking contemporaries. The concept of residual methane output is proposed as an appropriate trait to more equitably identify animals on the basis of low emissions beef production
  • Irish research response to dairy quality in an era of change

    O'Brien, Bernadette J.; Beresford, Tom; Cotter, Paul D.; Gleeson, D.; Kelly, A.; Kilcawley, Kieran; Magan, J.; McParland, Sinead; Murphy, E.; O’Callaghan, Tom; et al. (Teagasc, 2022-02-26)
    The Irish dairy sector is recognised for its very significant contribution to the national economic status; it is now worth ∼€5 billion annually and represents the largest food and drink export category, which, in turn, represents one of the four largest manufacturing industries in the country. Given anticipated further growth in global demand for dairy products and the positive attributes and capabilities that Ireland has to meet that demand, in terms of pasture-based production and cost competitiveness, it is incumbent for the sector to attain the highest quality milk and dairy products. The combined collaborative approach between research and industry has ensured significant progress and enabled Ireland to remain at the forefront globally in terms of production of quality milk and dairy products. This paper highlights some specific scientific platforms and technologies currently shaping the industry in this regard and discusses current research activity as well as anticipating key requirements for future progress. While research, and farm and processing plant management have accomplished very significant advances in milk and dairy product quality, some overarching emerging challenges include product substitution and sustainability. Some key pillars for the future have been identified on which a strong, efficient dairy sector can be maintained and progressed. Specifically, the use of evidence-based information and real-time measures in prediction and decision-making will be a crucial pillar for the dairy sector of the future. This can promote an approach of proactive maintenance and optimisation of production through improved predictability and control of manufacturing processes.
  • Animal welfare research – progress to date and future prospects

    Boyle, Laura A; Conneely, M.; Kennedy, Emer; O’Connell, N.; O'Driscoll, Keelin; Earley, Bernadette (Teagasc, 2022-02-26)
    RECORDABSTRACTARTICLE Animal welfare research – progress to date and future prospects OTHER Author(s): L. Boyle 1 , M. Conneely 1 , E. Kennedy 1 , N. O’Connell 2 , K. O’Driscoll 1 , B. Earley 3 , Publication date (Electronic): 26 February 2022 Journal: Irish Journal of Agricultural and Food Research Publisher: Compuscript Keywords: Animal welfare, beef, dairy, pig, poultry, welfare assessment Abstract The welfare status of an animal is dependent on its ability to cope and exist in harmony with its environment, such that good physical and psychological health is maintained. Improving animal welfare is an increasingly important aspect of livestock production systems due, in a large extent, to increased consumer concerns about animal production practices. Animal welfare is an integrated part of quality assurance programmes for sustainable animal production, considering that welfare, health, management, economy, consumer acceptance and environmental impact are interdependent. The major welfare concerns in the livestock industry in recent years relate to the rearing and management of dairy calves, the welfare of the dairy cow, effect of husbandry management procedures on the welfare of beef cattle, rearing of sows in gestation and farrowing crates, and the broiler (meat) chicken sector. The paper will focus on scientific research underpinning these welfare concerns, with a particular focus on research conducted on the island of Ireland.
  • The development of effective ruminant breeding programmes in Ireland from science to practice

    Berry, Donagh; Dunne, F.L.; McHugh, Noirin; McParland, Sinead; O’Brien, A.C.; Twomey, A.J. (Teagasc, 2022-02-25)
    A genetic improvement programme is a sustainable, cumulative and permanent approach to achieving year-on-year performance gains. Its success is predicated not only on an efficient and effective breeding programme but also on a vision of the traits of importance in the future. A single, industry-owned, centralised database for cattle and sheep has been the foundation for genetic improvement programmes in Ireland. While DNA information has been heralded as a breakthrough for accelerating genetic gain, the basic principles of a successful animal breeding programme still remain the same: (1) a pertinent breeding goal, (2) the appropriate breeding objective to deliver on the breeding goal, (3) an accurate genetic evaluation system, (4) an efficient and effective breeding scheme, and (5) a system to disseminate the elite germplasm to the end user; also of importance is a system for validating the underlying procedures and principles. The constituent traits and their relative emphasis within breeding objectives will continue to be contentious. Traits that will need to be considered more in future ruminant breeding objectives include environmental impact, product quality and animal well-being, including health; while not always explicitly included in Irish breeding objectives for cattle and sheep, indirect improvements for many are expected via the genetic improvement in traits like reproductive performance and survival as well as macro measures of quality such as milk fat and protein concentration and carcass merit. Crucial for the future sustainability of ruminant production systems is the co-evolution of management systems and breeding programmes so that the animal of the future is suited to the most sustainably efficient production system.
  • Dietary supplementation with fish oil and safflower oil, during the finishing period, alters brisket muscle fatty acid profile and n-6/n-3 ratio but not carcass traits of dairy beef bulls

    Byrne, C. J.; Fair, S.; Dick, J. R.; Lonergan, P.; Kenny, David A.; Department of Agriculture, Food and the Marine; 11/S/116 (American Registry of Professional Animal Scientists, 2021-08)
    Objective: With increases in the global population, there is a need to identify strategies that increase beef output while maintaining or improving health benefits of beef products. Studies have demonstrated that there are many benefits to human health in response to reducing the dietary n-6 to n-3 ratio. The aim of this study was to characterize the carcass characteristics and brisket muscle fatty acid profile of young dairy bred bulls following dietary supplementation with n-6 or n-3 polyunsaturated fatty acids (PUFA). Material and Methods: Holstein-Friesian (n = 43) and Jersey (n = 7) bulls with a mean ± s.e.m. age and bodyweight of 420.1 ± 5.86 days and 382.0 ± 8.94 kg, respectively, were offered a cereal based concentrate diet on an ad libitum basis, fortified with one of three lipid supplements: control (CTL; no supplementary lipid), n-6 PUFA safflower (SO), or n-3 PUFA enriched fish oil (FO). Bulls were individually offered their respective diet for 12 weeks prior to slaughter. Carcass weight, conformation and fat score were recorded at slaughter for all animals, while brisket muscle was collected from 26 randomly selected bulls and lipid profile analysed using GC. Results and Discussion: Total n-3 PUFA concentration was greater for FO than either SO or CTL diets (P < 0.05). Although there was no difference in the muscle total n-6 concentration between diets (P = 0.52), n-6 to n-3 ratio was 3.2 and 3.9 times lower for FO (P < 0.001) than either CTL or SO diets, respectively. Total intake of n-3 PUFA accounted for 72% of the variation in the n-6 to n-3 ratio. Despite the differences in fatty acid profiles, there was no effect of dietary lipid supplementation on carcass weight (P = 0.63), conformation (P = 0.79), or fat score (P = 0.84. Implications and Applications: Beef producers can feed n-6 and/or n-3 PUFA enriched diets that would result in beef having potential health benefits and greater branding potential.
  • Performance of lactating suckler cows of diverse genetic merit and genotype under a seasonal pasture-based system

    McCabe, S.; McHugh, Noirin; O'Connell, N. E.; Prendiville, Robert (Teagasc, 2021-12-21)
    The objective of this study was to investigate the effect of genetic merit of the national Irish maternal index and genotype (i.e. beef vs. beef × dairy [BDX]) of beef cows and subsequent performance of their progeny. With the exception that high genetic merit cows produced 0.57 kg more milk and tended to have 0.04 of a lower body condition score (BCS), no significant differences were observed between cows of diverse genetic merit. Differences between contrasting cow genotype were apparent. Beef cows were 50 kg heavier and had a BCS 0.27 greater than BDX cows. The BDX cows produced 1.67 kg more milk and had a greater 24-d submission rate than beef cows. Calves generated from BDX cows were 19 kg heavier at weaning and were worth €51 more than progeny generated from beef cows. Beef cow progeny, however, had 0.77 of a greater conformation score at slaughter than BDX. While differences were observed across cows of different replacement strategies, results from the current study showed that genetic selection for national maternal index had no effect on the overall performance of suckler cows in a pasture-based spring-calving system.
  • Evaluating the effectiveness of commercial teat disinfectant products sold in Ireland using the disc diffusion method

    Fitzpatrick, S.R.; Garvey, M.; Flynn, J.; O'Brien, Bernadette; Gleeson, David; Teagasc Walsh Scholarship Programme; 2016054 (Teagasc, 2021-06-04)
    Evaluation of teat disinfectant products for their effectiveness against the most prevalent mastitis-causing bacteria is important to identify the most effective ingredients against specific bacterial strains. Ninety-six commercially available teat disinfectant products were tested against three bacterial strains associated with mastitis in Ireland (Staphylococcus aureus, Streptococcus uberis and Escherichia coli) using the disc diffusion method. Products were reclassified by active ingredients (n = 9) for analysis. These ingredient groups included: chlorhexidine (n = 25), chlorine dioxide (n = 5), diamine (n = 1), iodine (n = 13), iodine combined with lactic acid (n = 5), lactic acid (n = 15), lactic acid combined with chlorhexidine (n = 21), lactic acid combined with hydrogen peroxide (n = 1) and lactic acid combined with salicylic acid (n = 10). The ingredient group chlorine dioxide resulted in the greatest zones of inhibition for all three bacterial strains. An individual product containing a combination of lactic acid and hydrogen peroxide resulted in the greatest zone of inhibition for Sta. aureus and Str. uberis, whereas a specific product within the chlorine dioxide group resulted in the greatest zones of inhibition for E. coli. High concentrations of active ingredient did not necessarily increase the effectiveness for the majority of teat disinfectant products. It is possible to use the disc diffusion method to evaluate/screen a large number of teat disinfectant products prior to conducting field trials to establish the products’ ability to reduce intramammary infections (IMI).
  • Enhancing muscle fatty acid profile by pasture finishing within a dairy-origin calf-to-steer beef production system and its potential to authenticate the dietary history of the cattle

    Moloney, Aidan; Keane, Michael G.; Monahan, F. J.; O'Callaghan, Tom (Teagasc, 2021-11-18)
    The influence of modifying a traditional 24-mo dairy steer calf to beef production system on the fatty acid composition of the longissimus muscle and its potential to authenticate beef provenance was examined. Fifty-four male calves (n = 18 per sire breed), progeny of Holstein-Friesian cows mated with Holstein-Friesian (HF), Aberdeen Angus (AA) and Belgian Blue (BB) bulls were at pasture from March until August of their second year when they were assigned to a 3 (breed types) × 3 (finishing strategies) factorial experiment. The three finishing strategies were (i) pasture only for a further 94 d prior to slaughter (21 mo of age) (Grass), (ii) concentrates ad libitum indoors for 94 d prior to slaughter (21 mo of age) (EC) and (iii) pasture only for a further 94 d followed by concentrates ad libitum indoors for 98 d prior to slaughter (24 mo of age) (LC). Compared to EC, muscle from Grass had a lower intramuscular fat concentration and omega-6: omega-3 polyunsaturated fatty acid (PUFA) ratio and higher proportion of conjugated linoleic acid. A longer period at pasture pre-concentrate finishing increased the concentration of omega-3 PUFA which was still lower than in Grass. To maximise the omega-3 PUFA concentration, a late-maturing breed is more appropriate while to maximise conjugated linoleic acid, an early-maturing breed is more appropriate and both should be finished on grass. Chemometric analysis confirmed that the fatty acid profile can authenticate “Grass-Finished” beef per se and has potential to distinguish “Concentrate-Finished” beef based on the length of grazing prior to finishing, but not distinguish between sire breeds.
  • Manipulation of the pre-partum diet of dairy cows to promote early adaptation to perennial ryegrass herbage

    Russo, V.M.; Wales, W.J.; Leury, B.J.; Hannah, M.C.; Kennedy, Emer; Teagasc; Agriculture Victoria Research; Dairy Australia; University of Melbourne (Teagasc, 2021-11-18)
    The diet of dairy cows in Ireland traditionally changes abruptly from predominantly pasture silage before calving to grazed perennial ryegrass immediately after calving. This potentially leads to problems with adaptation of microbes in the rumen with consequences of reduced intake and ultimately lower milk production. This experiment aimed to determine if introducing first-lactation dairy cows to perennial ryegrass herbage in the final weeks of pregnancy, thus eliminating a major dietary change at calving, could improve the adaptation process, potentially increasing dry matter intake (DMI) and milk production in early lactation. Three weeks prior to their expected calving date, 14 spring calving dairy cows were assigned to one of two treatments (n = 7): pasture silage pre-partum and perennial ryegrass herbage post-partum, or perennial ryegrass herbage both pre- and post-partum. Treatment diets were fed for 11 (±7) d pre-partum and for 14 (±0) d post-partum. For both treatments, DMI increased post-partum, but there was no difference between treatments, pre- or post-partum (5.9 and 8.8 kg DM/cow per day, respectively). There were no differences in milk yield or composition between the treatments. Body condition score declined following parturition but there were no differences between treatments. Plasma non-esterified fatty acids, glucose and β-hydroxybutyrate were also unaffected by treatment but did indicate a state of negative energy balance in early lactation. The results of this experiment suggest that pre-partum adaptation to perennial ryegrass herbage would not benefit milk production in first-lactation dairy cows in early lactation in Irish dairy farms employing this system.
  • Managing the Calf at Calving Time

    Mee, John F (American Association of Bovine Practitioners, 2008)
    Perinatal mortality rates are increasing internationally, particularly in Holstein-Friesian primiparae. The prevalence of perinatal mortality in US dairy herds is currently 8%. This article outlines our current knowledge of bovine perinatal pathophysiology and presents practical guidelines on management of the calf at calving time. Biophysical profiling of the newborn calf, without sophisticated equipment, is the first step in diagnosing at-risk perinates. Resuscitative techniques adaptable for both the producer and the veterinarian are detailed. In addition, management of prolonged recumbence, hypothermia, failure to suck, umbilical antisepsis and calf movement after calving are discussed. Knowledge gaps constraining future progress towards better newborn calf management are highlighted. Finally, current topics in perinatal mortality are presented.
  • Sward type alters the relative abundance of members of the rumen microbial ecosystem in dairy cows

    Smith, Paul E.; Enriquez-Hidalgo, Daniel; Hennessy, Deirdre; McCabe, Matthew S.; Kenny, David A.; Kelly, Alan K.; Waters, Sinéad M.; FACCE ERA GAS; Irish Dairy Levy Trust; European Union; et al. (Springer Science and Business Media LLC, 2020-06-09)
    The performance of ruminant livestock has been shown to beneft from the enhanced nutritive value and herbage yield associated with clover incorporation in the grazing sward. However, little research to date has been conducted investigating the efects of mixed swards containing white clover on the composition of the rumen microbiome. In this study, the rumen microbial composition of late lactation dairy cows grazing perennial ryegrass only (PRG; n=20) or perennial ryegrass and white clover (WCPRG; n=19) swards, was characterised using 16S rRNA amplicon sequencing. PERMANOVA analysis indicated diet signifcantly altered the composition of the rumen microbiome (P=0.024). Subtle shifts in the relative abundance of 14 bacterial genera were apparent between diets, including an increased relative abundance of Lachnospira (0.04 vs. 0.23%) and Pseudobutyrivibrio (1.38 vs. 0.81%) in the WCPRG and PRG groups, respectively. The composition of the archaeal community was altered between dietary groups, with a minor increase in the relative abundance of Methanosphaera in the WCPRG observed. Results from this study highlight the potential for sward type to infuence the composition of the rumen microbial community.
  • Experimental challenge with bovine respiratory syncytial virus in dairy calves: bronchial lymph node transcriptome response

    Johnston, Dayle; Earley, Bernadette; McCabe, Matthew S.; Lemon, Ken; Duffy, Catherine; McMenamy, Michael; Cosby, S. Louise; Kim, JaeWoo; Blackshields, Gordon; Taylor, Jeremy F.; et al. (Springer Science and Business Media LLC, 2019-10-14)
    Bovine Respiratory Disease (BRD) is the leading cause of mortality in calves. The objective of this study was to examine the response of the host’s bronchial lymph node transcriptome to Bovine Respiratory Syncytial Virus (BRSV) in a controlled viral challenge. Holstein-Friesian calves were either inoculated with virus (103.5TCID50/ml×15ml) (n=12) or mock challenged with phosphate bufered saline (n=6). Clinical signs were scored daily and blood was collected for haematology counts, until euthanasia at day 7 post-challenge. RNA was extracted and sequenced (75bp paired-end) from bronchial lymph nodes. Sequence reads were aligned to the UMD3.1 bovine reference genome and diferential gene expression analysis was performed using EdgeR. There was a clear separation between BRSV challenged and control calves based on gene expression changes, despite an observed mild clinical manifestation of the disease. Therefore, measuring host gene expression levels may be benefcial for the diagnosis of subclinical BRD. There were 934 diferentially expressed genes (DEG) (p<0.05, FDR <0.1, fold change >2) between the BRSV challenged and control calves. Over-represented gene ontology terms, pathways and molecular functions, among the DEG, were associated with immune responses. The top enriched pathways included interferon signaling, granzyme B signaling and pathogen pattern recognition receptors, which are responsible for the cytotoxic responses necessary to eliminate the virus.
  • Effect of Early Calf-Hood Nutrition on the Transcriptional Regulation of the Hypothalamic-Pituitary-Testicular axis in Holstein-Friesian Bull Calves

    English, A. M.; Byrne, C. J.; Cormican, P; Waters, S. M.; Fair, S.; Kenny, D. A.; Department of Agriculture, Food and the Marine; Irish Research Council; 11/S/116; GOIPG/2013/1391 (Springer Science and Business Media LLC, 2018-11-08)
    The aim of this study was to investigate the effect of early calf-hood nutrition on the transcriptomic profile of the arcuate nucleus of the hypothalamus, anterior pituitary and testes in Holstein-Friesian bulls. Holstein-Friesian bull calves with a mean (±S.D.) age and bodyweight of 19 (±8.2) days and 47.5 (±5.3) kg, respectively, were offered a high (n = 10) or low (n = 10) plane of nutrition in order to achieve an overall growth rate of 1.2 and 0.5 kg/day. At 126 (±3) days of age, calves were euthanized, hypothalamus (arcuate region), anterior pituitary and testicular parenchyma samples were harvested and RNAseq analysis was performed. There were 0, 49 and 1,346 genes differentially expressed in the arcuate nucleus, anterior pituitary and testicular tissue of bull calves on the low relative to the high plane of nutrition, respectively (P < 0.05; False Discovery Rate <0.05). Cell cycle processes in the anterior pituitary were down regulated in the low relative to the high plane of nutrition; there was no differential expression of genes related to reproductive processes. Gene expression involved in cholesterol and androgen biosynthesis in the testes were down regulated in animals on the low plane of nutrition. This study provides insight into the effect of early life plane of nutrition on the regulation of the HPT axis.
  • Heart to spine measurements to detect left atrial enlargement in dogs with mitral insufficiency

    Sánchez Salguero, Xavier; Prandi, David; Llabrés-Díaz, Francisco; Manzanilla, Edgar G.; Badiella, Llorenç; Bussadori, Claudio (Springer Science and Business Media LLC, 2019-11-20)
    Background: Radiography is useful to determine left atrial (LA) size when echocardiography is not available. Recently, the authors have described Radiographic Left Atrial Dimension (RLAD) as a new radiographic measurement to assess LA size. The objective of this study was to assess the clinical usefulness of 2 new radiographic measurements to detect and quantify left atrial enlargement (LAE) compared to RLAD and using left atrium to aortic root (LA/Ao) ratio as gold standard. These new measurements, bronchus-to-spine (Br-Spine) and RLAD-to-spine (RLAD-Spine) may be more precise in cases were LA boundaries are not well defined. Fifty dogs, 25 with and 25 without LAE were recruited. Reference LA/Ao ratio was assessed by 2D echocardiography and LAE was considered if LA/Ao > 1.6. Br-spine was measured as a straight vertical line from the main stem bronchus to the ventral border of the vertebra situated immediately dorsal to the heart base. RLAD-Spine was measured from RLAD endpoint perpendicularly to spine. The correlation of RLAD, Br-Spine and RLAD-Spine methods with LA/Ao and their sensitivity and specificity for detecting LAE were calculated. Receiver Operating Characteristic (ROC) curves were used to estimate the optimal cut-off for each method. Results: Correlations between Br-Spine, RLAD-Spine, RLAD and LA/Ao ratio were − 0.66, − 0.76 and 0.89 respectively (P < 0.001). Sensitivity at the optimal cut-off values for detecting LAE were 32.0, 64.0 and 96.0%, respectively. Specificity was 96.0% in all cases. Conclusion: Br-Spine and RLAD-Spine were less sensitive radiographic measurements than RLAD in detecting LAE in dogs. Both Br-Spine and RLAD-Spine may not be good alternatives to RLAD.
  • Liver fluke in Irish sheep: prevalence and associations with management practices and co-infection with rumen fluke

    Munita, Maria Pia; Rea, Rosemary; Martinez-Ibeas, Ana Maria; Byrne, Noel; McGrath, Guy; Munita-Corbalan, Luis Enrique; Sekiya, Mary; Mulcahy, Grace; Sayers, Ríona G.; Department of Agriculture, Food and the Marine; et al. (Springer Science and Business Media LLC, 2019-11-06)
    Background: The present study aimed to identify the national prevalence of Fasciola hepatica in Irish sheep and to conduct a risk analysis assessment based on management and treatment practices in participating focks. Also, co-infection with rumen fuke was quantifed and its association with liver fuke and management practices was assessed. Methods: A total of 305 sheep focks were selected ensuring even national representation of the sheep population. Participating farms were asked to complete a survey questionnaire on farm management practices and submit faecal samples during the winter of 2014–2015. Pooled faecal samples were analysed for the presence of F. hepatica and coinfection with rumen fuke. Apparent and true prevalence were calculated, additionally, the rate of co-infection with rumen fuke was also obtained. Correlation and regression analyses were used for assessing associations between management practices, liver fuke infection and co-infection with rumen fuke. Results: The national true prevalence of F. hepatica was 50.4% (n=305). Regional prevalence varied from 41% in the east to 52% in the south. Co-infection with rumen fuke was observed in 40% of the studied population and corre‑ lated with increased F. hepatica egg counts (OR=2.9; P≤0.001). Predominant breeds were Sufolk, Texel and Horned Mountain breeds. Beef cattle were the most frequent type of other livestock present on farms and mixed species grazing was frequently reported (73%). More than half of the focks reported a mid-to-late lambing period (MarchApril). Use of mountain land for grazing was of 32%. Flukicides were most commonly used twice over the autumnwinter period. Regression analyses highlighted signifcant association of F. hepatica status, with the presence of other livestock on farm, frequency of fukicides used during the winter and clinical presentation of liver fuke. A signifcant increase in eggs per gram of faeces was observed in Charollais sheep in comparison with all other breeds. Co-infec‑ tion with F. hepatica and Calicophoron daubneyi was also signifcantly associated with the presence of other livestock on the farm, type of fukicide used and clinical fasciolosis. Conclusions: The present study provides up-to-date information on the prevalence of F. hepatica in Irish sheep and adds insight to the epidemiology of the disease. These fndings will be useful for designing new holistic control meas‑ ures for F. hepatica infection.
  • Comparison of four commercially available ELISA kits for diagnosis of Fasciola hepatica in Irish cattle

    Munita, Maria Pia; Rea, Rosemary; Martinez-Ibeas, Ana Maria; Byrne, Noel; Kennedy, Aideen; Sekiya, Mary; Mulcahy, Grace; Sayers, Riona; Department of Agriculture, Food and the Marine; Dairy Research Ireland; et al. (Springer Science and Business Media LLC, 2019-11-21)
    Background: Fasciola hepatica is a liver parasite of mammals and it results in poor welfare outcomes and economic losses in ruminants. While faecal egg count is the test most commonly used for diagnosis, it does not indicate presence of migrating immature stages. Serological techniques increase sensitivity at all stages of the liver fluke infection. The aim of this study was to compare four commercially available ELISA tests for the diagnosis of F. hepatica. For this purpose, we tested three sample types; (i) known F. hepatica status sera from an experimental infection for the comparison of sensitivities and specificities, (ii) sera from pre- and post-flukicide-treated (albendazole, closantel, nitroxynil and triclabendazole) beef cattle to contrast the differences of seropositivity before and after treatment, and (iii) bulk tank milk samples from dairy herds sampled during high and low F. hepatica exposure periods for assessing seasonal variations with the four tests available. Samples were tested using ELISA kits supplied by four manufacturers (Ildana Biotech, IDEXX, Svanova, and Bio-X). Samples were analysed simultaneously and in duplicate. Results: In the control population Ildana, IDEXX and Bio-X presented 100% sensitivity (Se) and specificity (Sp), Svanovir presented a Se of 59% and a Sp of 96%. In flukicide-treated beef cattle, kits highlighted decreasing antibody levels 90 days post-treatment in variable degrees. Finally, bulk milk showed a significant decrease in ELISA value between high and low fluke exposure periods with all tests studied. Conclusions: Se and Sp found in the present study, confirm that Ildana, IDEXX and Bio-X are accurate for the detection of F. hepatica exposure in Irish cattle. Svanovir Se and Sp in this population, indicate that a larger study is necessary to confirm this test characteristic in Irish herds. In post-treatment use, Bio-X showed a consistent and significant decrease of ELISA value in all groups treated, denoting to be a reliable tool for assessing treatment effect at 90 days post-treatment. Finally, all tests showed to be a reliable tool for the F. hepatica monitoring of high and low exposure seasons, using bulk tank milk samples.
  • Reaffirmation of known major genes and the identification of novel candidate genes associated with carcass-related metrics based on whole genome sequence within a large multi-breed cattle population

    Purfield, D. C.; Evans, R. D.; Berry, D. P.; European Union; Science Foundation Ireland; No 727213; 14/IA/2576; 16/RC/3835 (BMC, 2019-09-18)
    Background: The high narrow sense heritability of carcass traits suggests that the underlying additive genetic potential of an individual should be strongly correlated with both animal carcass quality and quantity, and therefore, by extension, carcass value. Therefore, the objective of the present study was to detect genomic regions associated with three carcass traits, namely carcass weight, conformation and fat cover, using imputed whole genome sequence in 28,470 dairy and beef sires from six breeds with a total of 2,199,926 phenotyped progeny. Results: Major genes previously associated with carcass performance were identified, as well as several putative novel candidate genes that likely operate both within and across breeds. The role of MSTN in carcass performance was re-affirmed with the segregating Q204X mutation explaining 1.21, 1.11 and 5.95% of the genetic variance in carcass weight, fat and conformation, respectively in the Charolais population. In addition, a genomic region on BTA6 encompassing the NCAPG/LCORL locus, which is a known candidate locus associated with body size, was associated with carcass weight in Angus, Charolais and Limousin. Novel candidate genes identified included ZFAT in Angus, and SLC40A1 and the olfactory gene cluster on BTA15 in Charolais. Although the majority of associations were breed specific, associations that operated across breeds included SORCS1 on BTA26, MCTP2 on BTA21 and ARL15 on BTA20; these are of particular interest due to their potential informativeness in across-breed genomic evaluations. Genomic regions affecting all three carcass traits were identified in each of the breeds, although these were mainly concentrated on BTA2 and BTA6, surrounding MSTN and NCAPG/LCORL, respectively. This suggests that although major genes may be associated with all three carcass traits, the majority of genes containing significant variants (unadjusted p-value < 10− 4 ) may be trait specific associations of small effect. Conclusions: Although plausible novel candidate genes were identified, the proportion of variance explained by these candidates was minimal thus reaffirming that while carcass performance may be affected by major genes in the form of MSTN and NCAPG/LCORL, the majority of variance is attributed to the additive (and possibly multiplicative) effect of many polymorphisms of small effect.
  • Association of genetic polymorphisms related to Johne’s disease with estimated breeding values of Holstein sires for milk ELISA test scores

    Mallikarjunappa, Sanjay; Schenkel, Flavio S.; Brito, Luiz F.; Bissonnette, Nathalie; Miglior, Filippo; Chesnais, Jacques; Lohuis, Michae; Meade, Kieran G.; Karrow, Niel A; The Semex Alliance; et al. (Springer Open, 2020-05-27)
    Background: Johne’s disease (JD) is a chronic intestinal inflammatory disease caused by Mycobacterium avium subsp. paratuberculosis (MAP) infection in ruminants. Since there are currently no effective vaccine or treatment options available to control JD, genetic selection may be an alternative strategy to enhance JD resistance. Numerous Single Nucleotide Polymorphisms (SNPs) have been reported to be associated with MAP infection status based on published genome-wide association and candidate gene studies. The main objective of this study was to validate these SNPs that were previously identified to be associated with JD by testing their effect on Holstein bulls’ estimated breeding values (EBVs) for milk ELISA test scores, an indirect indicator of MAP infection status in cattle. Results: Three SNPs, rs41810662, rs41617133 and rs110225854, located on Bos taurus autosomes (BTA) 16, 23 and 26, respectively, were confirmed as significantly associated with Holstein bulls’ EBVs for milk ELISA test score (FDR < 0.01) based on General Quasi Likelihood Scoring analysis (GQLS) analysis. Single-SNP regression analysis identified four SNPs that were associated with sire EBVs (FDR < 0.05). This includes two SNPs that were common with GQLS (rs41810662 and rs41617133), with the other two SNPs being rs110494981 and rs136182707, located on BTA9 and BTA16, respectively. Conclusions: The findings of this study validate the association of SNPs with JD MAP infection status and highlight the need to further investigate the genomic regions harboring these SNPs.
  • Reproductive efficiency and survival of Holstein-Friesian cows of divergent Economic Breeding Index, evaluated under seasonal calving pasture-based management

    O'Sullivan, M; Butler, T S; Pierce, K M; Crowe, M; O'Sullivan, K; Fitzgerald, R; Buckley, F (Elsevier, 2020-02-29)
    The objective of the current study was to examine phenotypic fertility performance and survival, and to gain insight into underlying factors that may contribute to greater fertility performance in 2 divergent genetic groups (GG) of Holstein-Friesian, selected using the Irish Economic Breeding Index (EBI). The GG were evaluated across 3 spring calving pasture-based feeding treatments (FT) over 4 yr. The 2 divergent GG were (1) high EBI; representative of the top 5% nationally (elite), and (2) EBI representative of the national average (NA). In each year, 90 elite and 45 NA cows were randomly allocated to 1 of 3 FT: control, lower grass allowance, and high concentrate. No interaction between GG and FT was observed for any of the measures of fertility investigated. The elite cows achieved significantly greater pregnancy rate to first service (+14.9 percentage points), and significantly greater pregnancy rates after 21, 42, and 84 d of breeding (+17.3, +15.2, and +9.6 percentage points, respectively) compared with NA. The number of services per cow was fewer for elite (1.57) compared with NA (1.80). The interval from mating start date to pregnancy was significantly shorter for elite cows compared with NA. The elite cows maintained greater mean body condition score than NA throughout the study (2.91 vs. 2.72), and had greater body condition score at calving, artificial insemination, and drying off compared with NA. The elite cows had greater mean circulating concentrations of insulin-like growth factor-1 compared with NA. No significant effect was observed of GG on commencement of luteal activity, or progesterone profile variables. Greater survival to the start of fifth lactation was observed for elite cows. The elite cows were 43% less likely to be culled than NA by the beginning of the fifth lactation. The results highlight the success of the Economic Breeding Index to deliver reproductive performance and longevity consistent with industry targets across a range of seasonal pasture-based FT. The results also clearly demonstrate the potential of appropriate genetic selection to reverse negative fertility trends incurred during previous decades of selection for milk production alone.
  • Ver la ceguera

    Mee, John F (Anembe, 2019)
    El síndrome de la ceguera de granja afecta tanto a ganaderos como a veterinarios y es necesario conocer sus causas para poder atajarlo.

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