• Gains in dry matter yield and herbage quality from breeding perennial ryegrass

      Wilkins, P.W.; Lovatt, J.A. (Teagasc (Agriculture and Food Development Authority), Ireland, 2011)
      During the last 100 years, in Western Europe and elsewhere, considerable effort has been devoted to improving perennial ryegrass (Lolium perenne L.) for agriculture. The first persistent cultivars to be widely used were more digestible than other common pasture species but were no higher yielding than the better wild populations of perennial ryegrass. Two main approaches (here called mainstream breeding and population improvement) have been used to further improve the species for the UK, but no recent experiments to assess progress have been published. In 2006, two plot trials were established at IBERS to compare the performance of some newer cultivars and candidate varieties with the first persistent cultivars to be widely used in the UK. One trial involved comparing 10 intermediate-heading (6 diploid and 4 tetraploid) cultivars and candidate varieties with the intermediate-heading cv. Talbot, and the other involved comparing 11 late-heading (4 diploid and 7 tetraploid) cultivars and candidate varieties with the late-heading cv. S23. During 2007 to 2009, one silage cut and 6 other cuts were harvested each year, annual dry matter (DM) yields were determined and DM samples analysed for in vitro DM digestibility (DMD), water soluble carbohydrate (WSC) and crude protein (CP) concentrations in the DM. Percentage ground covered by perennial ryegrass in November 2009 was estimated visually. Twenty of the 21 cultivars were significantly (12 to 38%) higher yielding, 15 were significantly (10 to 27 g/kg) higher in mean DMD, 15 were significantly (25 to 58 g/kg) higher in mean WSC and 7 (all diploids) were significantly higher in ground cover in autumn of the third harvest year than their respective control cultivars. There were no significant differences among the varieties in mean CP over all harvests. The newest intermediate-heading cultivar (the diploid Abermagic) produced 29% more DM, was 10 g/kg higher in DMD and 51 g/kg higher in WSC, and had significantly better ground cover at the end of the third harvest year than Talbot. The newest late-heading cultivar (the tetra-ploid Aberbite) produced 28% more DM than S23 and was 22 g/kg higher in DMD and 58g/kg higher in WSC, although it was similar to S23 for ground cover at the end of the third harvest year. Both of these new varieties were developed entirely or partly by population improvement at IBERS over 26 years (1980 to 2005). These results suggest that the rates of gain in DM yield under nitrogen-limiting conditions and in herbage WSC concentration from perennial ryegrass breeding can be improved by utilizing new technologies and better breeding strategies.
    • Gastrointestinal nematode control practices on lowland sheep farms in Ireland with reference to selection for anthelmintic resistance

      Patten, Thomas; Good, Barbara; Hanrahan, James P; Mulcahy, Grace; de Waal, Theo (Biomed Central, 2011-03-31)
      Gastrointestinal parasitism is a widely recognised problem in sheep production, particularly for lambs. While anthelmintics have a pivotal role in controlling the effects of parasites, there is a paucity of data on how farmers use anthelmintics. A representative sample of Irish lowland farmers were surveyed regarding their parasite control practices and risk factors that may contribute to the development of anthelmintic resistance. Questionnaires were distributed to 166 lowland Irish sheep producers. The vast majority of respondents treated their sheep with anthelmintics. Lambs were the cohort treated most frequently, the majority of farmers followed a set programme as opposed to treating at sign of disease. A substantial proportion (61%) administered four or more treatments to lambs in a 'normal' year. Departures from best practice in anthelmintic administration that would encourage the development of anthelmintic resistance were observed. In conclusion, in the light of anthelmintic resistance, there is a need for a greater awareness of the principles that underpin the sustainable use of anthelmintics and practices that preserve anthelmintic efficacy should be given a very high priority in the design of helminth control programmes on each farm. To this end, given that veterinary practitioners and agricultural advisors were considered to be the farmer's most popular information resource, the capacity of these professions to communicate information relating to best practice in parasite control should be targeted.
    • Gastrointestinal tract size, total-tract digestibility, and rumen microflora in different dairy cow genotypes

      Beecher, Marion; Buckley, Frank; Waters, Sinead M.; Boland, T. M.; Enriquez-Hidalgo, D.; Deighton, M. H.; O'Donovan, Michael; Lewis, Eva (Elsevier Inc and American Dairy Science Association, 2014-04-03)
      The superior milk production efficiency of Jersey (JE) and Jersey × Holstein-Friesian (JE × HF) cows compared with Holstein-Friesian (HF) has been widely published. The biological differences among dairy cow genotypes, which could contribute to the milk production efficiency differences, have not been as widely studied however. A series of component studies were conducted using cows sourced from a longer-term genotype comparison study (JE, JE × HF, and HF). The objectives were to (1) determine if differences exist among genotypes regarding gastrointestinal tract (GIT) weight, (2) assess and quantify whether the genotypes tested differ in their ability to digest perennial ryegrass, and (3) examine the relative abundance of specific rumen microbial populations potentially relating to feed digestibility. Over 3 yr, the GIT weight was obtained from 33 HF, 35 JE, and 27 JE × HF nonlactating cows postslaughter. During the dry period the cows were offered a perennial ryegrass silage diet at maintenance level. The unadjusted GIT weight was heavier for the HF than for JE and JE × HF. When expressed as a proportion of body weight (BW), JE and JE × HF had a heavier GIT weight than HF. In vivo digestibility was evaluated on 16 each of JE, JE × HF, and HF lactating dairy cows. Cows were individually stalled, allowing for the total collection of feces and were offered freshly cut grass twice daily. During this time, daily milk yield, BW, and dry matter intake (DMI) were greater for HF and JE × HF than for JE; milk fat and protein concentration ranked oppositely. Daily milk solids yield did not differ among the 3 genotypes. Intake capacity, expressed as DMI per BW, tended to be different among treatments, with JE having the greatest DMI per BW, HF the lowest, and JE × HF being intermediate. Production efficiency, expressed as milk solids per DMI, was higher for JE than HF and JE × HF. Digestive efficiency, expressed as digestibility of dry matter, organic matter, N, neutral detergent fiber, and acid detergent fiber, was higher for JE than HF. In grazing cows (n = 15 per genotype) samples of rumen fluid, collected using a transesophageal sampling device, were analyzed to determine the relative abundance of rumen microbial populations of cellulolytic bacteria, protozoa, and fungi. These are critically important for fermentation of feed into short-chain fatty acids. A decrease was observed in the relative abundance of Ruminococcus flavefaciens in the JE rumen compared with HF and JE × HF. We can deduce from this study that the JE genotype has greater digestibility and a different rumen microbial population than HF. Jersey and JE × HF cows had a proportionally greater GIT weight than HF. These differences are likely to contribute to the production efficiency differences among genotypes previously reported.
    • Gender Relations and Women’s Off-farm Employment: a critical analysis of discourses

      Hanrahan, Sheena (Teagasc, 2007-01-01)
      This project addresses gender relations on dairy farms in Irish Republic. Its aim was to explore the way women who are married to farmers but who are employed in paid employment off the farm are constructed in agricultural policy discourse. It was proposed that discourses encapsulate the values and interests of powerful actors and are constitutive in their effect. Hence they are implicated in women’s experience of life within a ‘farm family’. Following on from this it may be said that women’ s continued subordination in Irish farming or indeed their chances of achieving equal status are circumscribed by dominant discourses.
    • Gender, Power and Property: “In my own right”

      Byrne, Anne; Duvvury, Nata; Macken-Walsh, Aine; Watson, Tanya (Teagasc, Oak Park, Carlow, Ireland, 2013-11)
      Women on farms in Ireland are a subject of feminist analysis for five decades. Salient themes are the constraints of patriarchal agriculture (O'Hara 1997; Shortall, 2004), the invisibility of women's farm work (Viney 1968; O’Hara 1998), gender inequalities in ownership of farm assets (Watson et al. 2009) and increasing professionalisation of farmwomen outside of agriculture (Kelly and Shortall 2002; Hanrahan 2007). Most women enter farming through marriage and family ties. Land ownership is identified by Shortall (2004) as the critical factor underpinning male domination of the occupational category ‘farmer’ and considerable power differentials between men and women in family farming. This is an area that requires further investigation. Our analysis, framed by theoretical models of feminisation and empowerment, explores cases where male farm property ownership in Ireland is disrupted in conventional and non-conventional agricultural settings. Do these cases provide evidence of new opportunities for women to become farm property owners, and in what contexts? What consequences do these opportunities have for farmwomen’s empowerment and agency? How does women’s farm property ownership disturb rural gender relations in the context of the family farm?
    • GENEDEC

      Shrestha, Shailesh; Hennessy, Thia (Teagasc, 2007-01-01)
      GENEDEC was a European project funded under the 6th Framework. It was co-ordinated by INRA Grignon with ten European partners and a time frame of 42 months. The purpose of the project was to conduct a quantitative and qualitative assessment of the socio-economic and environmental impacts of the decoupling of direct payments on agricultural production, markets and land use in the EU. It was envisaged that the pan-EU nature of the project would facilitate an international comparison of the effects of decoupling and would provide policy makers with sufficient information to identify the key winners and losers from decoupling throughout the EU. The project aimed to provide insights into the workability of decoupling and its impacts, and to analyse alternative policy options to improve the agricultural support system. Specifically, through the use of farm level models, this project estimated the effects of existing and proposed decoupled support schemes on production, land use and land prices and the implications for farm incomes and the future structural development of farms. The project was divided into 9 Work Packages depending on objectives and time frame of the project. The main role of RERC Teagasc was in Work Package 2 which aimed to develop farm level mathematical models and used the models developed to determine the impact of decoupling on Irish farms. The work in RERC started in November 2004 and ended in May 2006. A brief description of the models developed and results generated by RERC is provided here.
    • A general method for selection of riboflavin-overproducing food grade micro-organisms

      Burgess, Catherine M; Smid, Eddy J; Rutten, Ger; van Sinderen, Douwe (Biomed Central, 2006-07-18)
      Background: This study describes a strategy to select and isolate spontaneous riboflavin-overproducing strains of Lactobacillus (Lb.) plantarum, Leuconostoc (Lc.) mesenteroides and Propionibacterium (P.) freudenreichii. Results: The toxic riboflavin analogue roseoflavin was used to isolate natural riboflavin-overproducing variants of the food grade micro-organisms Lb. plantarum, Lc. mesenteroides and P. freudenreichii strains. The method was successfully employed for strains of all three species. The mutation(s) responsible for the observed overproduction of riboflavin were identified for isolates of two species. Conclusion: Selection for spontaneous roseoflavin-resistant mutants was found to be a reliable method to obtain natural riboflavin-overproducing strains of a number of species commonly used in the food industry. This study presents a convenient method for deriving riboflavin-overproducing strains of bacterial starter cultures, which are currently used in the food industry, by a non-recombinant methodology. Use of such starter strains can be exploited to increase the vitamin content in certain food products.
    • Generating Phenotypic Diversity in a Fungal Biocatalyst to Investigate Alcohol Stress Tolerance Encountered during Microbial Cellulosic Biofuel Production

      Hennessy, Rosanna C.; Doohan, Fiona; Mullins, Ewen (PLOS, 2013-10-16)
      Consolidated bioprocessing (CBP) of lignocellulosic biomass offers an alternative route to renewable energy. The crop pathogen Fusarium oxysporum is a promising fungal biocatalyst because of its broad host range and innate ability to co-saccharify and ferment lignocellulose to bioethanol. A major challenge for cellulolytic CBP-enabling microbes is alcohol inhibition. This research tested the hypothesis that Agrobacterium tumefaciens - mediated transformation (ATMT) could be exploited as a tool to generate phenotypic diversity in F. oxysporum to investigate alcohol stress tolerance encountered during CBP. A random mutagenesis library of gene disruption transformants (n=1,563) was constructed and screened for alcohol tolerance in order to isolate alcohol sensitive or tolerant phenotypes. Following three rounds of screening, exposure of select transformants to 6% ethanol and 0.75% n-butanol resulted respectively in increased (≥11.74%) and decreased (≤43.01%) growth compared to the wild –type (WT). Principal component analysis (PCA) quantified the level of phenotypic diversity across the population of genetically transformed individuals and isolated candidate strains for analysis. Characterisation of one strain, Tr. 259, ascertained a reduced growth phenotype under alcohol stress relative to WT and indicated the disruption of a coding region homologous to a putative sugar transporter (FOXG_09625). Quantitative PCR (RT-PCR) showed FOXG_09625 was differentially expressed in Tr. 259 compared to WT during alcohol-induced stress (P<0.05). Phylogenetic analysis of putative sugar transporters suggests diverse functional roles in F. oxysporum and other filamentous fungi compared to yeast for which sugar transporters form part of a relatively conserved family. This study has confirmed the potential of ATMT coupled with a phenotypic screening program to select for genetic variation induced in response to alcohol stress. This research represents a first step in the investigation of alcohol tolerance in F. oxysporum and has resulted in the identification of several novel strains, which will be of benefit to future biofuel research.
    • Generation of Bioactive Hydrolysates and Peptides from Bovine Hemoglobin with In Vitro Renin, Angiotensin-I-Converting Enzyme and Dipeptidyl Peptidase-IV Inhibitory Activities

      Lafarga, Tomas; Rai, Dilip K.; O'Connor, Paula; Hayes, Maria (Wiley, 2016-03-02)
      Bovine hemoglobin was selected for use in the generation of bioactive hydrolysates with potential for use as functional food ingredients for prevention of disorders such as hypertension, obesity and diabetes. Bovine hemoglobin was isolated and hydrolyzed with papain, which was selected using in silico analysis. The generated hydrolysate was enriched by ultrafiltration and further purified by high performance liquid chromatography. A number of peptides were identified using de novo peptide sequencing and these peptides were chemically synthesized to confirm their bioactivity in vitro. Three multifunctional peptides with both, ACE-I and renin-inhibitory properties and one peptide with ACE-I-inhibiting properties were identified. These included the di-peptide HR with ACE-I and renin IC50 values of 0.19 and 7.09 mM, respectively. The generated papain hydrolysate of bovine hemoglobin not only inhibited the enzymes ACE-I and renin but also the enzyme DPP-IV, which has been linked to type-2 diabetes.
    • Genetic Analysis of Irish Populations of Phytophthora Infestans

      Dowley, L.J.; O'Sullivan, E.; Griffin, D.; Harmey, M. (Teagasc, 2000-09-01)
      Phytophthora infestans (Mont.) de Bary, the causal agent of potato late blight is best known for its role in the great Irish famine of 1845-1849 which resulted in the deaths of over 1 million people. Since then, the disease has become established in all potato growing countries and is the most important pathogen of potatoes worldwide. The appearance of resistance to the phenylamide fungicides in the late 1970’s indicated that populations of P. infestans were changing. An antiresistance strategy was developed for growers in an effort to reduce the spread of resistant strains. Subsequently the A2 mating type of the fungus was discovered in 1989 promoting fears that a super strain of the fungus could evolve through sexual reproduction. Populations of the fungus have been monitored from 1981 to 1998 for levels of phenylamide resistance and since 1988 for the A2 mating type. Physiological race surveys were conducted in 1983 and 1996. Prior to the 1980s no reliable methods were available for adequate identification of genotypes. Development of molecular markers specific to P. infestans has made this possible and a survey was conducted on isolates from the 1996 population. Results confirm that the anti-resistance strategy for phenylamide based fungicides has been effective in preventing the build up of metalaxyl resistant populations of P. infestans. During the 1990’s the distribution of phenylamide resistance has remained stable at about 50% of crops tested compared to a high of over 80 % in 1981. The level of A2 in the population has also fallen from a high of 35% of isolates tested in 1989 to a static level of 3-4 % in the 1990’s. Physiological race composition has become much more complex since 1983 and 16 different physiological races were found in Ireland in 1996. The population was dominated by race 3.4.7.10.11 which accounted for over 54% of isolates tested. This change has taken place without a corresponding change to varieties with a complex Rgene base. Twelve different genotypes of the fungus were uncovered using the multilocus probe RG57. Races of the fungus were independent of genotype. One particular genotype IE-2 was predominantly associated with phenylamide resistance. The low population diversity discovered suggests that sexual reproduction between A1 and A2 types has not been a major factor in disease epidemiology to date. Super strains similar to those identified in the USA could not be confirmed. The overall level of variation in the Irish isolates of Phytophthora infestans would confirm that the population has become progressively more diverse during the last forty years. However, the population is much less complex than that found in the highland tropics of central Mexico.
    • Genetic and non-genetic factors affecting lamb growth and carcass quality.

      Hanrahan, J.P. (Teagasc, 1999-05-01)
      The work undertaken under this project concerned the effects of genetic and non-genetic factors on lamb growth, both pre and post-weaning, and carcass traits. The principal objective of the genetic studies was to estimate the performance effects of selecting terminal sires on the basis of the lean meat index (LMI) which is produced for pedigree lambs in flocks that participate in the national Breed Improvement Programme operated by the Department of Agriculture and Food. The merits of the Beltex breed, recently introduced to this country, were also evaluated on comparisons with Texel and Suffolk sires. Estimates of within-breed genetic variation for growth and carcass traits were obtained.
    • Genetic basis of benzimidazole resistance in Teladorsagia circumcincta in Ireland

      Keegan, Jason D; Good, Barbara; de Waal, Theo; Fanning, June; Keane, Orla M (Biomed Central, 2017-02-13)
      Resistance to benzimidazole (BZ) anthelmintics is common in ovine nematodes of economic importance. Single nucleotide polymorphisms (SNP) at three positions in the isotype 1 β– tubulin gene have been associated with BZ resistance and molecular tests for the detection of BZ resistance have been developed. In order to determine if such tests are practicable in Ireland the polymorphisms associated with BZ resistance must be identified. To this end, BZ-resistant nematodes were recovered from four farms in Ireland. Resistant Teladorsagia circumcincta, Cooperia curticei and Trichostrongylus colubriformis were recovered, with resistant T. circumcincta the most common and the only species studied further. Sequencing of the isotype 1 β–tubulin gene from resistant T. circumcincta identified a T - A transition, resulting in an F200Y substitution known to be responsible for BZ-resistance, on three of the farms. However, on the fourth farm the frequency of the resistant A allele was only 0.33 indicating another BZ resistance mechanism may be present on this farm. An additional polymorphism resulting in a substitution of glutamate for leucine (E198L) was also found on this farm at low frequency (0.17). No polymorphisms at position 167 were identified on any farm. Therefore, molecular tests to detect BZ resistance in T. circumcincta in Ireland could prove useful; however, they may result in some instances of resistance remaining undetected.
    • Genetic merit for fertility traits in Holstein cows: I. Production characteristics and reproductive efficiency in a pasture-based system

      Cummins, S.B.; Lonergan, P.; Evans, A.C.O.; Berry, Donagh P.; Evans, Ross D; Butler, Stephen T. (American Dairy Science Association and Elsevier Inc., 2012-03)
      The objective of the present study was to characterize the phenotypic performance of cows with similar proportions of Holstein genetics, similar genetic merit for milk production traits, but with good (Fert+) or poor (Fert−) genetic merit for fertility traits. Specifically, we tested the hypothesis that cows with a negative estimated breeding value for calving interval would have superior fertility performance and would have detectable differences in body reserve mobilization and circulating concentrations of metabolic hormones and metabolites compared with cows that had a positive estimated breeding value for calving interval. For the duration of the study, cows were managed identically as a single herd in a typical grass-based, spring-calving production system. A total of 80 lactation records were available from 26 Fert+ and 26 Fert− cows over 2 consecutive years (2008 and 2009). During yr 1, cows were monitored during a 20-wk breeding season to evaluate reproductive performance. Milk production, body condition score (scale 1 to 5), body weight, grass dry matter intake, energy balance, and metabolic hormone and metabolite data were collected during both years. The Fert+ cows had greater daily milk yield (19.5 vs. 18.7 kg/d), shorter interval from calving to conception (85.6 vs. 113.8 d), and fewer services per cow (1.78 vs. 2.83). No difference between groups in grass dry matter intake, energy balance, or body weight was observed. The Fert+ cows maintained greater BCS during mid (2.84 vs. 2.74 units) and late lactation (2.82 vs. 2.73 units). Circulating concentrations of insulin-like growth factor-I were greater throughout the gestation-lactation cycle in Fert+ cows (148.3 vs. 128.2 ng/mL). The Fert+ cows also had greater circulating concentrations of insulin during the first 4 wk of lactation (1.71 vs. 1.24 μIU/mL). Analysis of records from national herd data verified the association between genetic merit for fertility traits and phenotypic reproductive performance; Fert+ cows (n = 2,436) required 11.1 d less to recalve than did Fert− cows (n = 1,388), and the percentage of cows that successfully calved for the second time within 365 and 400 d of the first calving was 8 and 13% greater for Fert+ compared with Fert− cows, respectively. These results demonstrate that genetic merit for fertility traits had a pronounced effect on reproductive efficiency, BCS profiles, and circulating concentrations of insulin-like growth factor-I.
    • Genetic merit for fertility traits in Holstein cows: II. Ovarian follicular and corpus luteum dynamics, reproductive hormones and estrus behaviour

      Cummins, Sean B; Lonergan, P.; Evans, A.C.O.; Butler, Stephen T. (American Dairy Science Association and Elsevier Inc., 2012-07)
      The objective of this study was to characterize the estrous cycle of cows with similar proportions of Holstein genetics, similar genetic merit for milk production traits, but with good (Fert+) or poor (Fert-) genetic merit for fertility traits. A total of 37 lactating cows were enrolled on an 8-d CIDR-based protocol to synchronise estrus. 19 Fert+ and 12 Fert- cows that successfully ovulated a dominant follicle and established a corpus luteum underwent daily transrectal ultrasonography. Blood sampling was carried at 8 h intervals from d 0 to d 6 and from d 15 to ovulation, and once daily from d 7 to d 15. Blood samples were analysed for progesterone, estradiol, follicle stimulating hormone and luteinising hormone. Estrus behaviour was recorded using neck activity collars and mounting pads. Fert+ cows tended to have fewer (P = 0.07) follicular waves (2.2 vs. 2.7 waves) and had a shorter (P < 0.05) estrous cycle (21.0 vs. 25.1 d) than Fert- cows. There was no effect of genotype on day of first wave emergence or day of first wave dominant follicle peak diameter (all P > 0.05) but the peak diameter of the first wave dominant follicle tended to be larger (P = 0.08) in Fert- cows. During the first 13 d of the cycle, Fert+ cows developed a corpus luteum that was 16% larger (P = 0.08) than Fert- cows. Circulating progesterone concentrations were 34% greater (P < 0.001) in Fert+ than Fert- cows (5.15 vs. 3.84 ng/ml, respectively) from d 5 to d 13. During the final follicular wave, the interval from preovulatory follicle emergence to ovulation and the interval from preovulatory follicle dominance to ovulation were similar (P >0.05) in both genotypes. Maximum preovulatory follicle diameter was larger (P < 0.05) in Fert+ than Fert- cows (17.9 vs. 16.8 mm, respectively); however, circulating concentrations of oestradiol were not different (all P > 0.05) between genotypes. A greater proportion (P < 0.05) of Fert- cows ovulated to a silent heat than Fert+ cows (22% vs. 2%, respectively). Of cows that showed behavioural estrus Fert+ cows had 41% greater (P < 0.01) mean activity count; however, no difference (P > 0.05) was seen in mounting behaviour between genotypes. These results demonstrate for the first time that genetic merit for fertility has pronounced effects on corpus luteum development, progesterone concentration, preovulatory follicle diameter and behavioural estrus.
    • Genetic merit for fertility traits in Holstein cows: III. Hepatic expression of somatotropic axis genes during pregnancy and lactation

      Cummins, Sean B; Waters, Sinead M.; Evans, A.C.O.; Lonergan, P.; Butler, Stephen T. (American Dairy Science Association and Elsevier Inc., 2012-07)
      The objective of this study was to characterize the circulating concentrations of insulin-like growth factor-I (IGF-I) and the hepatic expression of key genes regulating the somatotropic axis in cows divergent in genetic merit for fertility traits but with similar genetic merit for milk production traits. A total of 11 cows with good genetic merit for fertility (Fert+) and 12 cows with poor genetic merit for fertility (Fert−) underwent liver biopsy by percutaneous punch technique on d 20 (± 6.7 d) prepartum and on d 2 (± 1.5 d), d 58 (± 3.7 d), d 145 (± 13 d), and d 245 (± 17.1 d) postpartum. Total RNA was isolated and the mRNA expression of growth hormone receptor (GHR 1A and GHRtot), IGF-I, janus tyrosine kinase 2 (JAK2), signal transducer and activator of transcription 5B (STAT5B), suppressor of cytokine signaling 3 (SOCS-3), acid-labile subunit (ALS), and IGF-binding proteins (IGFBP1 to IGFBP6) were measured by real-time quantitative PCR. During lactation, the circulating concentrations of IGF-I were 34% greater in Fert+ cows. The Fert+ cows had increased mean expression of IGF-I mRNA during the study; however, the difference in IGF-I mRNA abundance between Fert+ and Fert− cows was most pronounced at d 145 and 245. The expression of IGFBP3 and ALS transcript was similar in Fert+ and Fert− cows for the duration of the study. The Fert− cows, however, had greater expression of IGFBP2, IGFBP4, IGFBP5, and IGFBP6. Genotype had no effect on mRNA abundance of GHR 1A, STAT5B, JAK2, or SOCS-3. Genetic merit for fertility traits affects hepatic expression of key genes of the somatotropic axis regulating the synthesis, bioavailability, and stability of circulating IGF-I.
    • Genetic parameters for milk mineral content and acidity predicted by mid-infrared spectroscopy in Holstein–Friesian cows

      Toffanin, V.; Penasa, M.; McParland, Sinead; Berry, Donagh P.; Cassandro, M.; De Marchi, M. (Cambridge University PRess, 2015-01-13)
      The aim of the present study was to estimate genetic parameters for calcium (Ca), phosphorus (P) and titratable acidity (TA) in bovine milk predicted by mid-IR spectroscopy (MIRS). Data consisted of 2458 Italian Holstein−Friesian cows sampled once in 220 farms. Information per sample on protein and fat percentage, pH and somatic cell count, as well as test-day milk yield, was also available. (Co)variance components were estimated using univariate and bivariate animal linear mixed models. Fixed effects considered in the analyses were herd of sampling, parity, lactation stage and a two-way interaction between parity and lactation stage; an additive genetic and residual term were included in the models as random effects. Estimates of heritability for Ca, P and TA were 0.10, 0.12 and 0.26, respectively. Positive moderate to strong phenotypic correlations (0.33 to 0.82) existed between Ca, P and TA, whereas phenotypic weak to moderate correlations (0.00 to 0.45) existed between these traits with both milk quality and yield. Moderate to strong genetic correlations (0.28 to 0.92) existed between Ca, P and TA, and between these predicted traits with both fat and protein percentage (0.35 to 0.91). The existence of heritable genetic variation for Ca, P and TA, coupled with the potential to predict these components for routine cow milk testing, imply that genetic gain in these traits is indeed possible.
    • Genetic relationships among linear type traits, milk yield, body weight, fertility and somatic cell count in primiparous dairy cows

      Berry, Donagh P.; Buckley, Frank; Dillon, Pat; Evans, Ross D; Veerkamp, R. F. (Teagasc (Agriculture and Food Development Authority), Ireland, 2004)
      Phenotypic and genetic (co)variances among type traits, milk yield, body weight, fertility and somatic cell count were estimated. The data analysed included 3,058 primiparous spring-calving Holstein-Friesian cows from 80 farms throughout the south of Ireland. Heritability estimates for the type traits varied from 0.11 to 0.43. Genetic correlations among some type traits were very strong and may indicate the possibility of reducing the number of traits assessed on each animal; the genetic correlation between angularity and body condition score was –0.84. Genetic correlations between all type traits (except body condition score, udder depth and teat length) and milk yield were positive and ranged from 0.08 to 0.69. The possibility of selecting for body weight may be achievable within a national progeny-testing programme using type traits within a selection index. Moderate to strong genetic correlations existed between some type traits and the various fertility measures and somatic cell count indicating the opportunity of indirect selection for improved fertility and health of animals using type traits within a selection index; however, the standard errors of some of the genetic correlations were large and should thus be treated with caution. Genetically taller, wider, deeper, more angular cows with tighter, stronger, shallower udders were predisposed to have inferior pregnancy rates to first service and require more services.
    • Genetic relationships among linear type traits, milk yield, body weight, fertility and somatic cell count in primiparous dairy cows

      Berry, Donagh P.; Buckley, Frank; Dillon, Pat; Evans, Ross D; Veerkamp, Roel F (Teagasc (Agriculture and Food Development Authority), Ireland, 2004)
      Phenotypic and genetic (co)variances among type traits, milk yield, body weight, fertility and somatic cell count were estimated. The data analysed included 3,058 primiparous spring-calving Holstein-Friesian cows from 80 farms throughout the south of Ireland. Heritability estimates for the type traits varied from 0.11 to 0.43. Genetic correlations among some type traits were very strong and may indicate the possibility of reducing the number of traits assessed on each animal; the genetic correlation between angularity and body condition score was –0.84. Genetic correlations between all type traits (except body condition score, udder depth and teat length) and milk yield were positive and ranged from 0.08 to 0.69. The possibility of selecting for body weight may be achievable within a national progeny-testing programme using type traits within a selection index. Moderate to strong genetic correlations existed between some type traits and the various fertility measures and somatic cell count indicating the opportunity of indirect selection for improved fertility and health of animals using type traits within a selection index; however, the standard errors of some of the genetic correlations were large and should thus be treated with caution. Genetically taller, wider, deeper, more angular cows with tighter, stronger, shallower udders were predisposed to have inferior pregnancy rates to first service and require more services.
    • Genetic relationships between carcass cut weights predicted from video image analysis and other performance traits in cattle

      Pabiou, T.; Fikse, W. F.; Amer, P. R.; Cromie, A. R.; Nasholm, A.; Berry, Donagh P. (Cambridge University Press, 2012-04)
      The objective of this study was to quantify the genetic associations between a range of carcass-related traits including wholesale cut weights predicted from video image analysis (VIA) technology, and a range of pre-slaughter performance traits in commercial Irish cattle. Predicted carcass cut weights comprised of cut weights based on retail value: lower value cuts (LVC), medium value cuts (MVC), high value cuts (HVC) and very high value cuts (VHVC), as well as total meat, fat and bone weights. Four main sources of data were used in the genetic analyses: price data of live animals collected from livestock auctions, live-weight data and linear type collected from both commercial and pedigree farms as well as from livestock auctions and weanling quality recorded on-farm. Heritability of carcass cut weights ranged from 0.21 to 0.39. Genetic correlations between the cut traits and the other performance traits were estimated using a series of bivariate sire linear mixed models where carcass cut weights were phenotypically adjusted to a constant carcass weight. Strongest positive genetic correlations were obtained between predicted carcass cut weights and carcass value (min rg(MVC)50.35; max rg(VHVC)50.69), and animal price at both weaning (min rg(MVC)50.37; max rg(VHVC)50.66) and post weaning (min rg(MVC)50.50; max rg(VHVC)50.67). Moderate genetic correlations were obtained between carcass cut weights and calf price (min rg(HVC)50.34; max rg(LVC)50.45), weanling quality (min rg(MVC)50.12; max rg(VHVC)50.49), linear scores for muscularity at both weaning (hindquarter development: min rg(MVC)520.06; max rg(VHVC)50.46), post weaning (hindquarter development: min rg(MVC)50.23; max rg(VHVC)50.44). The genetic correlations between total meat weight were consistent with those observed with the predicted wholesale cut weights. Total fat and total bone weights were generally negatively correlated with carcass value, auction prices and weanling quality. Total bone weight was, however, positively correlated with skeletal scores at weaning and post weaning. These results indicate that some traits collected early in life are moderate-to-strongly correlated with carcass cut weights predicted from VIA technology. This information can be used to improve the accuracy of selection for carcass cut weights in national genetic evaluations.
    • Genetic relationships between detailed reproductive traits and performance traits in Holstein-Friesian dairy cattle

      Carthy, T. R.; Ryan, D. P.; Fitzgerald, A. M.; Evans, R.D.; Berry, Donagh P. (Elsevier for American Dairy Science Association, 2015-12-17)
      The objective of the study was to estimate the genetic relationships between detailed reproductive traits derived from ultrasound examination of the reproductive tract and a range of performance traits in Holstein-Friesian dairy cows. The performance traits investigated included calving performance, milk production, somatic cell score (i.e., logarithm transformation of somatic cell count), carcass traits, and body-related linear type traits. Detailed reproductive traits included (1) resumed cyclicity at the time of examination, (2) multiple ovulations, (3) early ovulation, (4) heat detection, (5) ovarian cystic structures, (6) embryo loss, and (7) uterine score, measured on a 1 (little or no fluid with normal tone) to 4 (large quantity of fluid with a flaccid tone) scale, based on the tone of the uterine wall and the quantity of fluid present in the uterus. (Co)variance components were estimated using a repeatability animal linear mixed model. Genetic merit for greater milk, fat, and protein yield was associated with a reduced ability to resume cyclicity postpartum (genetic correlations ranged from −0.25 to −0.15). Higher genetic merit for milk yield was also associated with a greater genetic susceptibility to multiple ovulations. Genetic predisposition to elevated somatic cell score was associated with a decreased likelihood of cyclicity postpartum (genetic correlation of −0.32) and a greater risk of both multiple ovulations (genetic correlation of 0.25) and embryo loss (genetic correlation of 0.32). Greater body condition score was genetically associated with an increased likelihood of resumption of cyclicity postpartum (genetic correlation of 0.52). Genetically heavier, fatter carcasses with better conformation were also associated with an increased likelihood of resumed cyclicity by the time of examination (genetic correlations ranged from 0.24 to 0.41). Genetically heavier carcasses were associated with an inferior uterine score as well as a greater predisposition to embryo loss. Despite the overall antagonistic relationship between reproductive performance and both milk and carcass traits, not all detailed aspects of reproduction performance exhibited an antagonistic relationship.