• Calf health from birth to weaning. I. General aspects of disease prevention

      Lorenz, Ingrid; Mee, John F; Earley, Bernadette; More, Simon J (Biomed Central, 2011-09-16)
      Calfhood diseases have a major impact on the economic viability of cattle operations. This is the first in a three part review series on calf health from birth to weaning, focusing on preventive measures. The review considers both pre- and periparturient management factors influencing calf health, colostrum management in beef and dairy calves and further nutrition and weaning in dairy calves.
    • Calf health from birth to weaning. III. Housing and management of calf pneumonia

      Lorenz, Ingrid; Earley, Bernadette; Gilmore, John; Hogan, Ian; Kennedy, Emer; More, Simon J (Biomed Central, 2011-10-21)
      Calfhood diseases have a major impact on the economic viability of cattle operations. A three part review series has been developed focusing on calf health from birth to weaning. In this paper, the last of the three part series, we review disease prevention and management with particular reference to pneumonia, focusing primarily on the pre-weaned calf. Pneumonia in recently weaned suckler calves is also considered, where the key risk factors are related to the time of weaning. Weaning of the suckler calf is often combined with additional stressors including a change in nutrition, environmental change, transport and painful husbandry procedures (castration, dehorning). The reduction of the cumulative effects of these multiple stressors around the time of weaning together with vaccination programmes (preconditioning) can reduce subsequent morbidity and mortality in the feedlot. In most studies, calves housed individually and calves housed outdoors with shelter, are associated with decreased risk of disease. Even though it poses greater management challenges, successful group housing of calves is possible. Special emphasis should be given to equal age groups and to keeping groups stable once they are formed. The management of pneumonia in calves is reliant on a sound understanding of aetiology, relevant risk factors, and of effective approaches to diagnosis and treatment. Early signs of pneumonia include increased respiratory rate and fever, followed by depression. The single most important factor determining the success of therapy in calves with pneumonia is early onset of treatment, and subsequent adequate duration of treatment. The efficacy and economical viability of vaccination against respiratory disease in calves remains unclear.
    • Candidate genes associated with the heritable humoral response to Mycobacterium avium ssp. paratuberculosis in dairy cows have factors in common with gastrointestinal diseases in humans

      McGovern, S. P.; Purfield, Deirdre C; Ring, Siobhan C.; Carthy, Tara; Graham, David A.; Berry, Donagh; Department of Agriculture, Food and the Marine; Science Foundation Ireland; 14/IA/2576; 16/RC/3835 (Elsevier, 2019-03-07)
      Infection of cattle with bovine paratuberculosis (i.e., Johne's disease) is caused by Mycobacterium avium ssp. paratuberculosis (MAP) and results in a chronic incurable gastroenteritis. This disease, which has economic ramifications for the cattle industry, is increasing in detected prevalence globally; subclinically infected animals can silently shed the bacterium into the environment for years, exposing contemporaries and hampering disease-control programs. The objective of the present study was to first quantify the genetic parameters for humoral response to MAP in dairy cattle. This was followed by a genome-based association analysis and subsequent downstream bioinformatic analyses from imputed whole genome sequence SNP data. After edits, ELISA test records were available on 136,767 cows; analyses were also undertaken on a subset of 33,818 of these animals from herds with at least 5 MAP ELISA-positive cows, with at least 1 of those positive cows being homebred. Variance components were estimated using univariate animal and sire linear mixed models. The heritability calculated from the animal model for humoral response to MAP using alternative phenotype definitions varied from 0.02 (standard error = 0.003) to 0.05 (standard error = 0.008). The genome-based associations were undertaken within a mixed model framework using weighted deregressed estimated breeding values as a dependent variable on 1,883 phenotyped animals that were ≥87.5% Holstein-Friesian. Putative susceptibility quantitative trait loci (QTL) were identified on Bos taurus autosome 1, 3, 5, 6, 8, 9, 10, 11, 13, 14, 18, 21, 23, 25, 26, 27, and 29; mapping the most significant SNP to genes within and overlapping these QTL revealed that the most significant associations were with the 10 functional candidate genes KALRN, ZBTB20, LPP, SLA2, FI3A1, LRCH3, DNAJC6, ZDHHC14, SNX1, and HAS2. Pathway analysis failed to reveal significantly enriched biological pathways, when both bovine-specific pathway data and human ortholog data were taken into account. The existence of genetic variation for MAP susceptibility in a large data set of dairy cows signifies the potential of breeding programs for reducing MAP susceptibility. Furthermore, the identification of susceptible QTL facilitates greater biological understanding of bovine paratuberculosis and potential therapeutic targets for future investigation. The novel molecular similarities identified between bovine paratuberculosis and human inflammatory bowel disease suggest potential for human therapeutic interventions to be translated to veterinary medicine and vice versa.
    • Capturing the economic benefit of Lolium perenne cultivar performance

      McEvoy, Mary; O'Donovan, Michael; Shalloo, Laurence; Department of Agriculture, Food and the Marine (Teagasc (Agriculture and Food Development Authority), Ireland, 2011)
      Economic values were calculated for grass traits of economic importance in Irish grass-based ruminant production systems. Traits considered were those that had the greatest potential to influence the profitability of a grazing system. These were: grass dry matter (DM) yield in spring, mid-season and autumn, grass quality (dry matter digestibility; DMD), 1st and 2nd cut silage DM yield and sward persistency. The Moorepark Dairy Systems Model was used to simulate a dairy farm. Economic values were calculated by simulating the effect of a unit change in the trait of interest while holding all other traits constant. The base scenario involved a fixed herd size and land area (40 ha), and an annual DM yield of 13 t/ha. The economic values generated under the base scenario were: € 0.152/kg for DM yield in spring, € 0.030/kg for DM yield in mid-season and € 0.103/kg for DM yield in autumn; € 0.001, € 0.008, € 0.010, € 0.009, € 0.008 and € 0.006 per 1 g/kg change in DMD for the months of April to September, respectively; € 0.03/kg for 1st cut silage DM yield, € 0.02/kg for 2nd cut silage DM yield; and − € 4.961 for a 1 percent reduction in persistency. Alternative scenarios were examined to determine the sensitivity of the economic values to changes in annual DM yield, sward utilisation and a scenario where silage production was the focus of the system. The economic values were used to calculate a total merit index for each of 20 perennial ryegrass cultivars based on production data from a 3 year plot study. The rank correlation between the merit index values for the cultivars under the base scenario and the scenario involving a reduction in herbage utilisation was 1.0, while that with the scenario involving reduced annual DM yield was 0.94. It is concluded that the total merit index can be used to identify cultivars that can generate the greatest economic contribution to a grass-based production system, regardless of system or intensity of grass production.
    • Carcass characteristics of cattle differing in Jersey proportion

      Berry, Donagh; Judge, Michelle; Evans, R. D.; Buckley, Frank; Cromie, A. R.; Science Foundation Ireland; Department of Agriculture, Food and Marine; Meat Technology Ireland; Enterprise Ireland; 16/RC/3835; et al. (Elsevier, 2018-09-27)
      Comparison of alternative dairy (cross-)breeding programs requires full appraisals of all revenues and costs, including beef merit. Few studies exist on carcass characteristics of crossbred dairy progeny originating from dairy herds as well as their dams. The objective of the present study was to quantify, using a national database, the carcass characteristics of young animals and cows differing in their fraction of Jersey. The data set consisted of 117,593 young animals and 42,799 cows. The associations between a combination of sire and dam breed proportion (just animal breed proportion when the dependent variable was on cows) with age at slaughter (just for young animals), carcass weight, conformation, fat score, price per kilogram, and total carcass value were estimated using mixed models that accounted for covariances among herdmates of the same sex slaughtered in close proximity in time; we also accounted for age at slaughter in young animals (which was substituted with carcass weight and carcass fat score when the dependent variable was age at slaughter), animal sex, parity of the cow or dam (where relevant), and temporal effects represented by a year-by-month 2-way interaction. For young animals, the heaviest of the dairy carcasses were from the mating of a Holstein-Friesian dam and a Holstein-Friesian sire (323.34 kg), whereas the lightest carcasses were from the mating of a purebred Jersey dam to a purebred Jersey sire which were 46.31 kg lighter (standard error of the difference = 1.21 kg). The young animal carcass weight of an F1 Holstein-Friesian × Jersey cross was 20.4 to 27.0 kg less than that of a purebred Holstein-Friesian animal. The carcass conformation of a Holstein-Friesian young animal was 26% superior to that of a purebred Jersey, translating to a difference of 0.78 conformation units on a scale of 1 to 15. Purebred Holstein-Friesians produced carcasses with less fat than their purebred Jersey counterparts. The difference in carcass price per kilogram among the alternative sire-dam breed combinations investigated was minimal, although large differences existed among the different breed types for overall carcass value; the carcass value of a Holstein-Friesian animal was 20% greater than that of a Jersey animal. Purebred Jersey animals required, on average, 21 d longer to reach a given carcass weight and fat score relative to a purebred Holstein-Friesian. The difference in age at slaughter between a purebred Holstein-Friesian animal and the mating between a Holstein-Friesian sire with a Jersey dam, and vice versa, was between 7.0 and 8.9 d. A 75.8-kg difference in carcass weight existed between the carcass of a purebred Jersey cow and that of a Holstein-Friesian cow; a 50% Holstein–Friesian-50% Jersey cow had a carcass 42.0 kg lighter than that of a purebred Holstein-Friesian cow. Carcass conformation was superior in purebred Holstein-Friesian compared with purebred Jersey cows. Results from this study represent useful input parameters to populate simulation models of alternative breeding programs on dairy farms, and to help beef farmers evaluate the cost-benefit of rearing, for slaughter, animals differing in Jersey fraction.
    • A case of bovine raw milk contamination with Listeria monocytogenes

      Hunt, Karen; Drummond, Niall; Murphy, Mary; Butler, Francis; Buckley, James F.; Jordan, Kieran; Teagasc Walsh Fellowship Programme; Department of Agriculture, Food and the Marine, Ireland; European Union (Biomed Central, 06/07/2012)
      During routine sampling of bulk raw milk on a dairy farm, the pathogenic bacteria Listeria monocytogenes was found to be a contaminant, at numbers < 100 cfu/ml. A strain with an indistinguishable pulsed-field gel electrophoresis pattern was isolated from the bulk milk two months later. Environmental swabs taken at the dairy environment were negative for the presence of L. monocytogenes, indicating a possible case of excretion of the L. monocytogenes directly into the milk. Milk samples were collected from the individual cows and analysed, resulting in the identification of L. monocytogenes excretion (at 280 cfu/ml) from one of the 4 mammary quarters of one dairy cow out of 180. When the infected cow was isolated from the herd, no L. monocytogenes was detected from the remaining herd. The pulsed-field gel electrophoresis pattern of the strain from the individual cow was indistinguishable from that originally isolated from the bulk milk. The infected cow did not show any clinical signs of disease, nor did the appearance of the milk have any physical abnormalities. Antibiotic treatment of the infected mammary quarter was found to be ineffective. This study shows that there can be risks associated with direct contamination of raw milk with L. monocytogenes.
    • A case study of the carbon footprint of milk from high-performing confinement and grass-based dairy farms

      O’Brien, Donal; Judith Louise, Capper; Garnsworthy, Phil; Grainger, Chris; Shalloo, Laurence; European Union; FP7-244983 (Elsevier, 2014-01-17)
      Life-cycle assessment (LCA) is the preferred methodology to assess carbon footprint per unit of milk. The objective of this case study was to apply an LCA method to compare carbon footprints of high-performance confinement and grass-based dairy farms. Physical performance data from research herds were used to quantify carbon footprints of a high-performance Irish grass-based dairy system and a top-performing United Kingdom (UK) confinement dairy system. For the US confinement dairy system, data from the top 5% of herds of a national database were used. Life-cycle assessment was applied using the same dairy farm greenhouse gas (GHG) model for all dairy systems. The model estimated all on- and off-farm GHG sources associated with dairy production until milk is sold from the farm in kilograms of carbon dioxide equivalents (CO2-eq) and allocated emissions between milk and meat. The carbon footprint of milk was calculated by expressing GHG emissions attributed to milk per tonne of energy-corrected milk (ECM). The comparison showed that when GHG emissions were only attributed to milk, the carbon footprint of milk from the Irish grass-based system (837 kg of CO2-eq/t of ECM) was 5% lower than the UK confinement system (884 kg of CO2-eq/t of ECM) and 7% lower than the US confinement system (898 kg of CO2-eq/t of ECM). However, without grassland carbon sequestration, the grass-based and confinement dairy systems had similar carbon footprints per tonne of ECM. Emission algorithms and allocation of GHG emissions between milk and meat also affected the relative difference and order of dairy system carbon footprints. For instance, depending on the method chosen to allocate emissions between milk and meat, the relative difference between the carbon footprints of grass-based and confinement dairy systems varied by 3 to 22%. This indicates that further harmonization of several aspects of the LCA methodology is required to compare carbon footprints of contrasting dairy systems. In comparison to recent reports that assess the carbon footprint of milk from average Irish, UK, and US dairy systems, this case study indicates that top-performing herds of the respective nations have carbon footprints 27 to 32% lower than average dairy systems. Although differences between studies are partly explained by methodological inconsistency, the comparison suggests that potential exists to reduce the carbon footprint of milk in each of the nations by implementing practices that improve productivity.
    • A catalogue of validated single nucleotide polymorphisms in bovine orthologs of mammalian imprinted genes and associations with beef production traits

      Magee, David A; Berkowicz, Erik W; Sikora, Klaudia M; Berry, Donagh; Park, Stephen D. E.; Kelly, Alan K; Sweeney, Torres; Kenny, David A.; Evans, R. D.; Wickham, Brian W.; et al. (Cambridge University Press, 2010-06)
      Genetic (or ‘genomic’) imprinting, a feature of approximately 100 mammalian genes, results in monoallelic expression from one of the two parentally inherited chromosomes. To date, most studies have been directed on imprinted genes in murine or human models; however, there is burgeoning interest in the effects of imprinted genes in domestic livestock species. In particular, attention has focused on imprinted genes that influence foetal growth and development and that are associated with several economically important production traits in cattle, sheep and pigs. We have re-sequenced regions in 20 candidate bovine imprinted genes in order to validate single nucleotide polymorphisms (SNPs) that may influence important production traits in cattle. Putative SNPs detected via re-sequencing were subsequently re-formatted for high-throughput SNP genotyping in 185 cattle samples comprising 138 performance-tested European Bos taurus (all Limousin bulls), 29 African B. taurus and 18 Indian B. indicus samples. Analysis of the resulting genotypic data identified 117 validated SNPs. Preliminary genotype–phenotype association analyses using 83 SNPs that were polymorphic in the Limousin samples with minor allele frequencies >0.05 revealed significant associations between two candidate bovine imprinted genes and a range of important beef production traits: average daily gain, average feed intake, live weight, feed conversion ratio, residual feed intake and residual gain. These genes were the Ras proteinspecific guanine nucleotide releasing factor gene ( RASGRF1) and the zinc finger, imprinted 2 gene ( ZIM2). Despite the relatively small sample size used in these analyses, the observed associations with production traits are supported by the purported biological function of the RASGRF1 and ZIM2 gene products. These results support the hypothesis that imprinted genes contribute significantly to important complex production traits in cattle. Furthermore, these SNPs may be usefully incorporated into future marker-assisted and genomic selection breeding schemes.
    • The CD4+ T cell methylome contributes to a distinct CD4+ T cell transcriptional signature in Mycobacterium bovis-infected cattle

      Doherty, Rachael; Whiston, Ronan; Cormican, Paul; Finlay, Emma K.; Couldrey, Christine; Brady, Colm; O’Farrelly, Cliona; Meade, Kieran G; Teagasc Walsh Fellowship Programme (Nature Publishing Group, 2016-08-10)
      We hypothesised that epigenetic regulation of CD4+ T lymphocytes contributes to a shift toward a dysfunctional T cell phenotype which may impact on their ability to clear mycobacterial infection. Combined RNA-seq transcriptomic profiling and Reduced Representation Bisulfite Sequencing identified 193 significantly differentially expressed genes and 760 differentially methylated regions (DMRs), between CD4+ T cells from M. bovis infected and healthy cattle. 196 DMRs were located within 10 kb of annotated genes, including GATA3 and RORC, both of which encode transcription factors that promote TH2 and TH17 T helper cell subsets respectively. Gene-specific DNA methylation and gene expression levels for the TNFRSF4 and Interferon-γ genes were significantly negatively correlated suggesting a regulatory relationship. Pathway analysis of DMRs identified enrichment of genes involved in the anti-proliferative TGF-β signaling pathway and TGFB1 expression was significantly increased in peripheral blood leukocytes from TB-infected cattle. This first analysis of the bovine CD4+ T cell methylome suggests that DNA methylation directly contributes to a distinct gene expression signature in CD4+ T cells from cattle infected with M. bovis. Specific methylation changes proximal to key inflammatory gene loci may be critical to the emergence of a non-protective CD4+ T cell response during mycobacterial infection in cattle.
    • Cervico-vaginal mucus (CVM) – an accessible source of immunologically informative biomolecules

      Adnane, Mounir; Meade, Kieran G; O’Farrelly, Cliona; Science Foundation Ireland; Health Research Board; Department of Agriculture, Food and the Marine; 12/Ia/1667; HRA_POR/2012/37; FIRM/ RSF/CoFoRD 2013–2016: ENRICH; FIRM/RSF/CoFoRD 2011-2015 (Springer Science and Business Media LLC, 2018-08-16)
      Cervico-vaginal mucus (CVM), the product of epithelial cells lining the uterus, cervix and vagina, is secreted to facilitate uterine lubrication and microbial clearance. Predominantly composed of water and mucins, CVM also contains high levels of immuno-active proteins such as immunoglobulin A (IgA), lactoferrin and lysozyme which protect against infection by blocking adhesion and mediating microbial killing. The repertoire of cytokines, chemokines and antimicrobial peptides is predominantly generated by the secretions of endometrial epithelial cells into the uterine lumen and concentrated in the CVM. The quantity and relative proportions of these inflammatory biomarkers are affected by diverse factors including the estrus cycle and health status of the animal and therefore potentially provide important diagnostic and prognostic indicators. We propose that measuring molecular signatures in bovine CVM could be a useful approach to identifying and monitoring genital tract pathologies in beef and dairy cows.
    • Changes in yield and composition of barley, wheat and triticale grains harvested during advancing stages of ripening

      Stacey, Pamela; O'Kiely, Padraig; Hackett, Richard; Rice, B.; O'Mara, Frank P.; Teagasc Walsh Fellowship Programme (Teagasc, Oak Park, Carlow, Ireland, 2006)
      This study involved an evaluation of the changes in grain yield, nutritive value, ensilability and harvesting losses of intensively managed winter cereals harvested during the advancing stages of ripening. Five cereal crops (barley cv. Regina and wheat cv. Madrigal in 2001; barley cv. Regina, wheat cv. Falstaff and triticale cv. Fidelio in 2002) were assessed. Twenty plots per crop were arranged in a randomised complete block design, with five times of harvest (four for barley in 2002) and four replicate blocks per harvest. Dry matter (DM) yields changed relatively little between harvest dates, but fresh yields declined (P < 0.001) over time due to the moisture loss associated with ripening. Time-course changes in indices of nutritive value, such as concentrations of crude protein, starch and ash, and organic matter digestibility, were relatively small and did not follow a consistent pattern. Ensilability indices, such as DM and watersoluble carbohydrate concentrations and buffering capacity, indicated that satisfactory fermentations were likely if such crops were ensiled; buffering capacity, generally declining with advancing maturity. Harvesting losses were not clearly related to growth stage at harvest. It is concluded that winter cereal grain (barley, wheat and triticale) DM yields and quality were relatively constant as ripening progressed from DM concentrations of around 550 to >800 g/kg.
    • Characterisation and expression profile of the bovine cathelicidin gene repertoire in mammary tissue

      Whelehan, Cormac J; Barry-Reidy, Anne; Meade, Kieran G; Eckersall, P David; Chapwanya, Aspinas; Narciandi, Fernando; Lloyd, Andrew T; O'Farrelly, Cliona; Department of Agriculture, Food and the Marine (Biomed Central, 2014-02-13)
      Abstract Background Cathelicidins comprise a major group of host-defence peptides. Conserved across a wide range of species, they have several functions related to host defence. Only one cathelicidin has been found in humans but several cathelicidin genes occur in the bovine genome. We propose that these molecules may have a protective role against mastitis. The aim of this study was to characterise the cathelicidin gene-cluster in the bovine genome and to identify sites of expression in the bovine mammary gland. Results Bioinformatic analysis of the bovine genome (BosTau7) revealed seven protein-coding cathelicidin genes, CATHL1-7, including two identical copies of CATHL4, as well as three additional putative cathelicidin genes, all clustered on the long arm of chromosome 22. Six of the seven protein-coding genes were expressed in leukocytes extracted from milk of high somatic cell count (SCC) cows. CATHL5 was expressed across several sites in the mammary gland, but did not increase in response to Staphylococcus aureus infection. Conclusions Here, we characterise the bovine cathelicidin gene cluster and reconcile inconsistencies in the datasets of previous studies. Constitutive cathelicidin expression in the mammary gland suggests a possible role for these host defence peptides its protection. Background Cathelicidins comprise a major group of host-defence peptides. Conserved across a wide range of species, they have several functions related to host defence. Only one cathelicidin has been found in humans but several cathelicidin genes occur in the bovine genome. We propose that these molecules may have a protective role against mastitis. The aim of this study was to characterise the cathelicidin gene-cluster in the bovine genome and to identify sites of expression in the bovine mammary gland. Results Bioinformatic analysis of the bovine genome (BosTau7) revealed seven protein-coding cathelicidin genes, CATHL1-7, including two identical copies of CATHL4, as well as three additional putative cathelicidin genes, all clustered on the long arm of chromosome 22. Six of the seven protein-coding genes were expressed in leukocytes extracted from milk of high somatic cell count (SCC) cows. CATHL5 was expressed across several sites in the mammary gland, but did not increase in response to Staphylococcus aureus infection. Conclusions Here, we characterise the bovine cathelicidin gene cluster and reconcile inconsistencies in the datasets of previous studies. Constitutive cathelicidin expression in the mammary gland suggests a possible role for these host defence peptides its protection.
    • Characterisation of dairy soiled water in a survey of 60 Irish dairy farms

      Minogue, Denis; French, Padraig; Bolger, Thomas; Murphy, Paul N. C. (Teagasc (Agriculture and Food Development Authority), Ireland, 2016-01-13)
      Dairy farming in Ireland generates an effluent known as dairy soiled water (DSW), which consists of a relatively dilute mixture of cow faeces, urine, spilt milk and detergents that is typically applied to grassland. However, relatively little is known about the volumes generated, nutrient content and management factors that influence volume and concentration. Sixty dairy farms that had a separate storage tank for storing DSW were selected for this study. The spatial distribution of the farms reflected the spatial distribution of dairy cows across the 26 counties of the Republic of Ireland, with each farm representing between 10,000 and 20,000 dairy cows. Samples were analysed for biochemical oxygen demand (BOD), ammonium N (NH4-N), total nitrogen (TN), potassium (K), phosphorus (molybdate-reactive and total) (MRP and TP) and dry matter (DM) content. Management characteristics and parlour properties were quantified. Factors influencing volume and concentration of DSW were determined using mixed model multiple regression analysis. On average, 9784 l (standard error 209 l) of DSW, including rainfall, was produced cow−1 year−1 and this contained significant quantities of total N, P and K (587, 80 and 568 mg l−1, respectively). A typical Irish dairy farm stocked at 1.9 cows ha−1 could therefore supply approximately 13, 2 and 12 kg ha−1 of total N, P and K, respectively, across the farm, annually to meet some of the nutrient requirements for herbage production and potentially replace some of the synthetic fertilizer use. Seventy one percent of samples were within the regulated concentration limits of soiled water for BOD (<2500 mg l−1), rising to 87% during the closed period for slurry spreading (mid October to mid-late January), while 81% were within the concentration limits for DM (<1% DM), rising to 94% during the closed period. The efficiency of a milking parlour (cows per unit, time taken) plays a key role in determining the volume of DSW generated. This, in turn, also influences the concentration of nutrients and other chemicals. Large variability was found in nutrient concentrations and this presents a challenge for effective nutrient management to maximise the fertilizer replacement value of DSW.
    • Characterisation of physiological and immunological responses in beef cows to abrupt weaning and subsequent housing

      Lynch, Eilish M; Earley, Bernadette; McGee, Mark; Doyle, Sean; Teagasc Walsh Fellowship Programme; John Hume Scholarship (Biomed Central, 2010-07-20)
      Background: Weaning involves the permanent separation of the calf from the dam and has been shown to be stressful for both. The objectives of this study were to characterise the effect of i) abrupt weaning and ii) subsequent housing on the extended physiological and immunological responses of beef cows. At weaning (day (d) 0, mean age of calf (s.d.) 212 (24.5) d), cows were abruptly separated from their calves and returned to the grazing area. After 35 d at pasture, cows were housed in a slatted floor shed and offered grass silage ad libitum plus a mineral-vitamin supplement daily. Rectal body temperature was recorded and blood samples were obtained on i) d 0 (weaning), 2, 7, 14, 21, 28, 35 and subsequently on ii) d 0 (housing), 2, 7, 14 and 21 for physiological, haematological and immunological measurements. Results: Post-weaning, concentration of cortisol and dehydroepiandrosterone were unchanged (P > 0.05). Rectal body temperature, neutrophil number and neutrophil: lymphocyte ratio increased (P < 0.01) on d 2 compared with pre-weaning baseline. Lymphocyte and neutrophil number decreased (P < 0.05) on d 2 to 7 and d 7 to 21, respectively, compared with pre-weaning baseline. Interferon-γ production decreased (P < 0.05) on d 2 compared with pre-weaning baseline. An increase (P < 0.05) in acute phase proteins, fibrinogen and haptoglobin was evident on d 2 to 35 compared with pre-weaning baseline. Concentration of glucose increased on d 2 to 28, whereas non-esterified fatty acid decreased on d 2 to 35 compared with pre-weaning baseline. Post-housing, concentrations of cortisol, rectal body temperature, total leukocyte number, and glucose were unchanged (P > 0.05). On d 2 post-housing, neutrophil number and neutrophil: lymphocyte ratio increased (P < 0.05), whereas lymphocyte number and concentrations of dehydroepiandrosterone, fibrinogen and non-esterified fatty acid decreased (P < 0.05) compared with pre-housing baseline. Concentration of haptoglobin increased (P < 0.05) on d 14 to 21 post-housing. Conclusions: A transitory increase in neutrophil number and decrease in lymphocyte number, increased neutrophil:lymphocyte ratio coupled with decreased interferon-γ production, and increased concentration of acute phase proteins indicate a stress response in cows post-weaning, whereas post-housing, changes were less marked.
    • Characterisation of the Whole Blood mRNA Transcriptome in Holstein-Friesian and Jersey Calves in Response to Gradual Weaning

      Johnston, Dayle; Earley, Bernadette; Cormican, Paul; Kenny, David A.; McCabe, Matthew; Kelly, Alan K; McGee, Mark; Waters, Sinead M.; Department of Agriculture, Food and the Marine; European Union; et al. (PLOS, 2016-08-01)
      Weaning of dairy calves is an early life husbandry management practice which involves the changeover from a liquid to a solid feed based diet. The objectives of the study were to use RNA-seq technology to examine the effect of (i) breed and (ii) gradual weaning, on the whole blood mRNA transcriptome of artificially reared Holstein-Friesian and Jersey calves. The calves were gradually weaned over 14 days (day (d) -13 to d 0) and mRNA transcription was examined one day before gradual weaning was initiated (d -14), one day after weaning (d 1), and 8 days after weaning (d 8). On d -14, 550 genes were differentially expressed between Holstein-Friesian and Jersey calves, while there were 490 differentially expressed genes (DEG) identified on d 1, and 411 DEG detected eight days after weaning (P < 0.05; FDR < 0.1). No genes were differentially expressed within breed, in response to gradual weaning (P > 0.05). The pathways, gene ontology terms, and biological functions consistently over-represented among the DEG between Holstein-Friesian and Jersey were associated with the immune response and immune cell signalling, specifically chemotaxis. Decreased transcription of several cytokines, chemokines, immunoglobulin-like genes, phagocytosis-promoting receptors and g-protein coupled receptors suggests decreased monocyte, natural killer cell, and T lymphocyte, chemotaxis and activation in Jersey compared to Holstein-Friesian calves. Knowledge of breed-specific immune responses could facilitate health management practices better tailored towards specific disease sensitivities of Holstein-Friesian and Jersey calves. Gradual weaning did not compromise the welfare of artificially-reared dairy calves, evidenced by the lack of alterations in the expression of any genes in response to gradual weaning.
    • Characteristics of feed efficiency within and across lactation in dairy cows and the effect of genetic selection

      Hurley, A. M.; Lopez-Villalobos, N.; McParland, Sinead; Lewis, Eva; Kennedy, Emer; O'Donovan, Michael; Burke, Jennifer L.; Berry, Donagh; Irish Department of Agriculture, Food and the Marine; European Union (Elsevier, 2017-11-23)
      The objective of the present study was to investigate the phenotypic inter- and intra-relationships within and among alternative feed efficiency metrics across different stages of lactation and parities; the expected effect of genetic selection for feed efficiency on the resulting phenotypic lactation profiles was also quantified. A total of 8,199 net energy intake (NEI) test-day records from 2,505 lactations on 1,290 cows were used. Derived efficiency traits were either ratio based or residual based; the latter were derived from least squares regression models. Residual energy intake (REI) was defined as NEI minus predicted energy requirements based on lactation performance; residual energy production (REP) was defined as net energy for lactation minus predicted energy requirements based on lactation performance. Energy conversion efficiency was defined as net energy for lactation divided by NEI. Pearson phenotypic correlations among traits were computed across lactation stages and parities, and the significance of the differences was determined using the Fisher r-to-z transformation. Sources of variation in the feed efficiency metrics were investigated using linear mixed models, which included the fixed effects of contemporary group, breed, parity, stage of lactation, and the 2-way interaction of parity by stage of lactation. With the exception of REI, parity was associated with all efficiency and production traits. Stage of lactation, as well as the 2-way interaction of parity by stage of lactation, were associated with all efficiency and production traits. Phenotypic correlations among the efficiency and production traits differed not only by stage of lactation but also by parity. For example, the strong phenotypic correlation between REI and energy balance (EB; 0.89) for cows in parity 3 or greater and early lactation was weaker for parity 1 cows at the same lactation stage (0.81), suggesting primiparous cows use the ingested energy for both milk production and growth. Nonetheless, these strong phenotypic correlations between REI and EB suggested negative REI animals (i.e., more efficient) are also in more negative EB. These correlations were further supported when assessing the effect on phenotypic performance of animals genetically divergent for feed intake and efficiency based on parental average. Animals genetically selected to have lower REI resulted in cows who consumed less NEI but were also in negative EB throughout the entire lactation. Nonetheless, such repercussions of negative EB do not imply that selection for negative REI (as defined here) should not be practiced, but instead should be undertaken within the framework of a balanced breeding objective, which includes traits such as reproduction and health.
    • Characteristics of offspring derived from conventional and X-sorted bovine sperm

      Maicas, C.; Hutchinson, I.A.; Cromie, A.R.; Lonergan, P.; Butler, Stephen; Teagasc Walsh Fellowship Programme (American Dairy Science Association, 2020-08)
      The objective of this retrospective study was to compare survival during the first year of life and adult performance of offspring derived from artificial insemination (AI) with X-sorted or conventional sperm processed from the same ejaculates. We analyzed a data set that included AI of dairy heifers and lactating cows with fresh conventional sperm (3 × 106 sperm per straw), fresh X-sorted sperm (1 or 2 × 106 sperm per straw), or frozen X-sorted sperm (2 × 106 sperm per straw). The data set contained records of 5,179 offspring born on 396 farms. Offspring were classified as born from conventional sperm (CONV) if they were the product of an insemination with fresh conventional sperm, or born from X-sorted sperm (SS) if they were product of any of the 3 X-sorted sperm treatments. Generalized linear mixed models were used to evaluate the effect of sperm treatment on (1) survival during the first year of life; (2) reproductive performance, lactation performance, and survival of female offspring; and (3) slaughter characteristics of male offspring. Stillbirth rates and mortality rates during the first 2 mo of life were greater for male calves (2.8 and 5.0%, respectively) than for female calves (1.6 and 2.0%, respectively). No differences between offspring derived from SS and CONV were detected for incidences of stillbirth or mortality during the first 12 mo of life within sex of calf. Reproductive performance, milk volume, milk fat, milk protein yields during first; second; and third lactations, and survival to third lactation did not differ between female offspring derived from CONV and SS. Across all age groups, CONV steers had heavier carcasses than SS steers (325.3 vs. 318.3 kg), but there were no differences in weight between CONV and SS steers within any of the age groups (≤24, 25–27, 28–30, and >30 mo of age). The distribution of slaughter age did not differ between CONV and SS steers when the analysis was restricted to herds that reared steers derived from both types of sperm. Carcass conformation and fat scores of steers were not affected by sperm treatment. There was no difference in carcass weight between young bulls (≤2 yr) derived from CONV or SS. In conclusion, the results provide no evidence of differences in survival during the first year of life between offspring derived from CONV or SS, or for any of the reproductive and lactation performance characteristics studied between female offspring derived from CONV or SS. Modest differences in carcass weight between CONV and SS steers were detected, but this may reflect differences in management and husbandry in the rearing herds rather than the sex-sorting process. A controlled study using steers derived from conventional or X-sorted sperm from split ejaculates and reared under the same husbandry conditions is needed to clarify whether there is a true difference in body weight gain due to the sex-sorting process.
    • Characterization of anogenital distance and its relationship to fertility in lactating Holstein cows

      Gobikrushanth, M.; Bruinje, T. C.; Colazo, M. G.; Butler, Stephen; Ambrose, D. J.; Growing Forward 2; Teagasc Walsh Fellowship Programme; # DA7642064 (Elsevier, 2017-09-21)
      Anogenital distance (AGD) serves as a marker for prenatal androgenization, reproductive development, and fertility in humans and rodents. The primary objectives of this observational study in lactating dairy cows were to (1) characterize the distribution and variability of AGD, (2) determine the relationship among AGD and potential postnatal AGD determinants of age and height, and (3) evaluate the associations between AGD and pregnancy to first artificial insemination (P/AI) and cumulative pregnancy by 250 d in milk (DIM) within parity groups (first, second, and third+ parities). The secondary objective was to evaluate the association between AGD and testosterone concentrations. The AGD (mm), age (yr), and height at hip (cm) at the time of AGD determination, and aforesaid reproductive outcomes were determined in 921 Holstein cows (first, second, and third+ parity; n = 360, 256, and 305, respectively). Plasma concentrations of testosterone were determined in a subset of 93 cows. Overall, AGD had a normal distribution and high variability [mean (±standard deviation); 131.0 ± 12.2 mm], was weakly associated with cow age and height (coefficient of determination = 0.09 and 0.04, respectively), and had an inverse relationship with P/AI in first- and second-parity cows, but not in third+ parity cows. For every 1 mm increase in AGD, the odds of P/AI decreased by 3.4 and 2.4% for first- and second-parity cows, respectively. The optimal AGD threshold to predict probability of P/AI was 127.1 mm for both first- (sensitivity: 66.4; specificity: 56.6%) and second-parity cows (sensitivity: 46.0; specificity: 70.4%). Accordingly, first- and second-parity cows were categorized into either short or long AGD (≤ or >127.1 mm), and associations with reproductive outcomes were evaluated. First-parity cows with long AGD had lower P/AI (30.9 vs. 53.6%) and decreased likelihood (hazard ratio: 0.68) of pregnancy by 250 DIM than those with short AGD. Similarly, second-parity cows with long AGD had reduced P/AI (28.3 vs. 44.4%) and a tendency for decreased likelihood (hazard ratio: 0.76) of pregnancy by 250 DIM than in cows with short AGD. The association between AGD and testosterone was weak and nonsignificant. In summary, AGD in Holstein cows was normally distributed, highly variable, and weakly associated with age and height. Besides, AGD had an inverse relationship with P/AI and cumulative pregnancy by 250 DIM in first- and second-parity cows; however, such a relationship was not evident in older (third+ parity) cows.
    • Characterization of best linear unbiased estimates generated from national genetic evaluations of reproductive performance, survival, and milk yield in dairy cows

      Dunne, F. L.; Kelleher, Margaret M.; Walsh, S.W.; Berry, Donagh; MultiRepro project; Department of Agriculture, Food and the Marine (Elsevier, 2018-05-16)
      Genetic evaluations decompose an observed phenotype into its genetic and nongenetic components; the former are termed BLUP with the solutions for the systematic environmental effects in the statistical model termed best linear unbiased estimates (BLUE). Geneticists predominantly focus on the BLUP and rarely consider the BLUE. The objective of this study, however, was to define and quantify the association between 8 herd-level characteristics and BLUE for 6 traits in dairy herds, namely (1) age at first calving, (2) calving to first service interval (CFS), (3) number of services, (4) calving interval (CIV), (5) survival, and (6) milk yield. Phenotypic data along with the fixed and random effects solutions were generated from the Irish national multi-breed dairy cow fertility genetic evaluations on 3,445,557 cows; BLUE for individual contemporary groups were collapsed into mean herd-year estimates. Data from 5,707 spring-calving herds between the years 2007 and 2016 inclusive were retained; association analyses were undertaken using linear mixed multiple regression models. Pearson coefficient correlations were used to quantify the relationships among individual trait herd-year BLUE, and transition matrices were used to understand the dynamics of mean herd BLUE estimates over years. Based on the mean annual trends in raw, BLUP, and BLUE, it was estimated that BLUE were associated with at least two-thirds of the improvement in CIV and milk production over the past 10 yr. Milk recording herds calved heifers for the first time on average 15 d younger, had an almost 2 d longer CFS but 2.3 d shorter CIV than non-milk-recording herds. Larger herd sizes were associated with worse BLUE for both CFS and CIV. Expanding herds and herds that had the highest proportion of cows born on the farm itself, on average, calved heifers younger and had shorter CIV. By separating the raw performance of a selection of herds into their respective BLUE and BLUP, it was possible to identify herds with inferior management practices that were being compensated by superior genetics; similarly, herds were identified with superior BLUE, but because of their inferior genetic merit, were not reaching their full potential. This suggests that BLUE could have a pivotal role in a tailored decision support tool that would enable producers to focus on the most limiting factor hindering them from achieving their maximum performance.
    • Characterization of the bovine salivary gland transcriptome associated with Mycobacterium avium subsp. paratuberculosis experimental challenge

      Mallikarjunappa, Sanjay; Adnane, Mounir; Cormican, Paul; Karrow, Niel A; Meade, Kieran G; Teagasc Walsh Fellowship Programme (Biomed Central, 2019-06-13)
      Background Mycobacterium avium subsp. paratuberculosis (MAP), the etiologic agent of Johne’s disease is spread between cattle via the fecal-oral route, yet the functional changes in the salivary gland associated with infection remain uncharacterized. In this study, we hypothesized that experimental challenge with MAP would induce stable changes in gene expression patterns in the salivary gland that may shed light on the mucosal immune response as well as the regional variation in immune capacity of this extensive gland. Holstein-Friesian cattle were euthanized 33 months’ post oral challenge with MAP strain CIT003 and both the parotid and mandibular salivary glands were collected from healthy control (n = 5) and MAP exposed cattle (n = 5) for histopathological and transcriptomic analysis. Results A total of 205, 21, 61, and 135 genes were significantly differentially expressed between control and MAP exposed cattle in dorsal mandibular (M1), ventral mandibular (M2), dorsal parotid (P1) and ventral parotid salivary glands (P2), respectively. Expression profiles varied between the structurally divergent parotid and mandibular gland sections which was also reflected in the enriched biological pathways identified. Changes in gene expression associated with MAP exposure were detected with significantly elevated expression of BoLA DR-ALPHA, BOLA-DRB3 and complement factors in MAP exposed cattle. In contrast, reduced expression of genes such as polymeric immunoglobin receptor (PIGR), TNFSF13, and the antimicrobial genes lactoferrin (LF) and lactoperoxidase (LPO) was detected in MAP exposed animals. Conclusions This first analysis of the transcriptomic profile of salivary glands in cattle adds an important layer to our understanding of salivary gland immune function. Transcriptomic changes associated with MAP exposure have been identified including reduced LF and LPO. These critical antimicrobial and immunoregulatory proteins are known to be secreted into saliva and their downregulation may contribute to disease susceptibility. Future work will focus on the validation of their expression levels in saliva from additional cattle of known infection status as a potential strategy to augment disease diagnosis.