• PastureBase Ireland: A grassland decision support system and national database

      Hanrahan, Liam; Geoghegan, Anne; O'Donovan, Michael; Griffith, Vincent; Ruelle, Elodie; Wallace, Michael; Shalloo, Laurence (Elsevier BV, 2017-04-15)
      PastureBase Ireland (PBI) is a web-based grassland management application incorporating a dual function of grassland decision support and a centralized national database to collate commercial farm grassland data. This database facilitates the collection and storage of vast quantities of grassland data from grassland farmers. The database spans across ruminant grassland enterprises – dairy, beef and sheep. To help farmers determine appropriate actions around grassland management, we have developed this data informed decision support tool to function at the paddock level. Individual farmers enter data through the completion of regular pasture cover estimations across the farm, allowing the performance of individual paddocks to be evaluated within and across years. To evaluate the PBI system, we compared actual pasture cut experimental data (Etesia cuts) to PBI calculated outputs. We examined three comparisons, comparing PBI outputs to actual pasture cut data, for individual DM yields at defoliation (Comparison 1), for cumulative annual DM yields including silage data (Comparison 2) and, for cumulative annual DM yields excluding silage data (Comparison 3). We found an acceptable accuracy between PBI outputs and pasture cut data when statistically analyzed using relative prediction error and concordance correlation coefficients for the measurement of total annual DM yield (Comparison 2), with a relative prediction error of 15.4% and a concordance correlation coefficient of 0.85. We demonstrated an application of the PBI system through analysis of commercial farm data across two years (2014–2015) for 75 commercial farms who actively use the system. The analysis showed there was a significant increase in DM yield from 2014 to 2015. The results indicated a greater variation in pasture growth across paddocks within farms than across farms.
    • Performance and feed intake of five beef suckler cow genotypes and pre-weaning growth of their progeny

      Murphy, B.M.; Drennan, Michael J; O'Mara, Frank P.; McGee, Mark; Teagasc Walsh Fellowship Programme (Teagasc, Oak Park, Carlow, Ireland, 2008)
      The effect of beef suckler cow genotype on feed intake, performance, milk yield and on pre-weaning growth of their progeny was determined over four lactations. The five cow genotypes examined were Limousin (L), Charolais (C), Limousin × Holstein-Friesian (LF), Limousin × (Limousin × Holstein-Friesian) (LLF) and Simmental × (Limousin × Holstein-Friesian) (SLF). The herd calved in spring and the progeny spent from April until weaning (October/ November) at pasture with their dams. Live weight (kg) at the start of the indoor winter period was greater (P < 0.001) for C (702) than L (616) cows who in turn were heavier than LF (552) and LLF (574), with SLF (582) being intermediate. Silage dry matter (DM) intake (kg /day) was greater (P < 0.01) for C and SLF cows than L and LLF, whereas LF were inter-mediate. Dry matter intake (kg/day) of zero-grazed grass did not differ (P > 0.05) between the genotypes but followed a similar trend to grass silage intake. The decrease in live weight over the indoor winter period was greater (P < 0.01) for L and C cows than for LLF and SLF, whereas LF were intermediate. The increase in live weight during the grazing season was greater (P < 0.01) for C cows than all except L, which were intermediate. Calving difficulty score was greater (P < 0.01) for C cows than LLF, L and SLF, whereas LF were intermediate. Birth weight of calves from LF cows was lower (P < 0.001) than C with L being intermediate, but greater than LLF, with SLF being intermediate. Milk yield (kg/day) was higher (P < 0.001) for LF (9.7) and SLF (8.7) cows than the other genotypes (5.5 to 7.0), which did not differ significantly. Pre-weaning live-weight gain was greater (P < 0.001) for progeny of LF cows than all other genotypes except SLF, which in turn were greater than L and C, with LLF being intermediate. In conclusion, calf pre-weaning growth was higher for cow genotypes with higher milk yield, which was also associated with higher cow DM intake.
    • Phosphorus and nitrogen losses from temperate permanent grassland on clay-loam soil after the installation of artificial mole and gravel mole drainage

      Valbuena-Parralejo, N.; Fenton, Owen; Tuohy, Patrick; Williams, M.; Lanigan, Gary; Humphreys, James; Teagasc Walsh Fellowship Programme; Department of Agriculture, Food and the MArine; RSF11152 (Elsevier, 2018-12-14)
      Mole (M) and gravel-mole (GM) drainage systems improve the permeability of soils with high clay contents. They collect and carry away infiltrating water during episodic rainfall events. Characterisation of nutrient fluxes (concentration and flows) in overland flow (OF) and in mole drain flow (MF) across sequential rainfall events is important for environmental assessment of such drainage systems. The objective of this study is to assess the impact of drainage systems on soil nutrient losses. Three treatments were imposed on grazed permanent grassland on a clay loam soil in Ireland (52°30′N, 08°12′W) slope 1.48%: undrained control (C), mole drainage (M) and gravel mole drainage (GM). Plots (100 m × 15 m) were arranged in a randomized complete block design with four replicated blocks. Nitrogen (N) and phosphorus (P) concentrations in OF, MF and groundwater (GW) were measured from each plot over 15 consecutive rainfall events. The results showed that M and GM (P < 0.05) deepened the watertable depth and decreased OF. M and GM increased losses of nitrate-N (22%) and ammonium-N (14%) in GW. Nitrate-N concentrations from all the flow pathways (mean and standard error (s.e.): 0.99 s.e. 0.10 mg L−1) were well below the 11.3 mg L−1 threshold for drinking water. Ammonium-N concentrations from all the flow pathways (mean: 0.64 s.e. 0.14 mg L−1) exceeded drinking water quality standards. On the other hand M and GM lowered total P losses (mean annual losses from C, M and GM: 918, 755 and 853 s.e. 14.1 g ha−1 year−1) by enhancing soil P sorption. Hence M and GM can be implemented on farms under similar management to that described in the present study with a minor impact on N (increased concentration on averaged 18% to GW) and P (reduced by on avenged 114 g ha−1 year−1).
    • Pig Farmers' Conference 2012: Proceedings from the Teagasc National Pig Conferences

      Lawlor, Peadar G; McKeon, Michael; Quinn, Amy; Norris, David; Owens, David; Boyle, Laura; McCutcheon, Gerard; Clarke, Seamas (Teagasc, 2012-10)
      Proceedings from the Teagasc National Pig Conferences which took place on 23 October in the Horse and Jockey Hotel, Tipperary and the 24 October in the Cavan Crystal Hotel, Cavan
    • Post-weaning growth, ultrasound and skeletal measurements, muscularity scores and carcass traits and composition of progeny of five beef suckler cow genotypes

      Murphy, B.M.; Drennan, Michael J; O'Mara, Frank P.; McGee, Mark; Teagasc Walsh Fellowship Programme (Teagasc, Oak Park, Carlow, Ireland, 2008)
      Post-weaning growth, ultrasound and skeletal measurements, muscularity scores, and carcass traits and composition of the progeny of spring-calving Limousin (L), Charolais (C), Limousin × Holstein-Friesian (LF), Limousin × (Limousin × Holstein-Friesian) (LLF) and Simmental × (Limousin × Holstein-Friesian) (SLF) cow genotypes was determined over 3 years. Bull and heifer progeny were slaughtered at ~460 and ~610 days of age, respectively. Post-weaning growth did not differ significantly between the genotypes. Progeny from LF and SLF cows had the highest (P<0.001) carcass gain per day of age, whereas progeny from L and C cows had the highest (P < 0.01) carcass conformation score and lowest (P < 0.001) fat score. The proportion of meat in the car¬cass was higher (P < 0.001) and bone lower (P < 0.001), and meat to bone ratio higher (P < 0.001) for the progeny of L cows than all other genotypes, which were similar. Carcass fat proportion was similar for progeny of L and C cows and lower (P < 0.001) than LLF and SLF, with LF being intermediate. The progeny from L cows tended to have the greatest proportion of hind-quarter in the carcass. Genotype effects were mini¬mal when the proportion of high-value cuts was expressed relative to weight of meat in the carcass and hind-quarter. In conclusion, there was no effect of cow genotype on the performance of their progeny from weaning to slaughter. However, crossbred cows with good maternal (milk) traits produced progeny with a higher carcass weight per day of age, whereas the purebred continental cows produced progeny with superior carcass classification traits.
    • Post-weaning performance and carcass characteristics of steer progency from different suckler cow breed types

      Drennan, Michael J; McGee, Mark; Keane, Michael G. (Teagasc (Agriculture and Food Development Authority), Ireland, 2005-04)
      In two experiments a total of 44 steer progeny of spring-calving Charolais (C) and Hereford × Friesian (HF) suckler cows and C sires were slaughtered at approximately 2 years of age. Following weaning they were offered silage and 1 kg of concentrate per head daily during a 5 month winter after which they spent 7 months at pasture. In Experiment 1, animals were given a silage/concentrate diet during a finishing period of either 95 or 152 days. In Experiment 2, steers were offered either a daily diet of silage plus 6 kg of concentrates or concentrates to appetite plus 5 kg of silage (fresh weight) during the final 140-day finishing period. Following slaughter, an 8-rib pistola from each animal was dissected. For the two experiments combined C and HF progeny had carcass weights of 372 and 385 (s.e. 6.1) kg, proportions of carcass as pistola of 467 and 454 (s.e. 2.8) g/kg and pistola meat proportions of 676 and 642 (s.e. 5.1) g/kg, respectively. All fat traits were lower for the C than HF progeny but there was no difference in carcass conformation score. Increasing slaughter weight increased carcass weight (P < 0.001), kidney plus channel fat weight (P < 0.001), and pistola fat proportion (P < 0.001) and decreased the proportions of carcass as pistola (P < 0.05), pistola meat (P < 0.01), and bone (P < 0.05). In conclusion, breed type had no effect on carcass growth but the C progeny had higher meat yield than the HF. Increasing slaughter weight increased fatness and reduced meat yield.
    • Post-weaning performance and carcass characteristics of steer progeny from different suckler cow breed types

      Drennan, Michael J; McGee, Mark; Keane, Michael G. (Teagasc (Agriculture and Food Development Authority), Ireland, 2005)
      In two experiments a total of 44 steer progeny of spring-calving Charolais (C) and Hereford × Friesian (HF) suckler cows and C sires were slaughtered at approximately 2 years of age. Following weaning they were offered silage and 1 kg of concentrate per head daily during a 5 month winter after which they spent 7 months at pasture. In Experiment 1, animals were given a silage/concentrate diet during a finishing period of either 95 or 152 days. In Experiment 2, steers were offered either a daily diet of silage plus 6 kg of concentrates or concentrates to appetite plus 5 kg of silage(fresh weight)during the final 140-day finishing period. Following slaughter, an 8-rib pistola from each animal was dissected. For the two experiments combined C and HF progeny had carcass weights of 372 and 385 (s.e. 6.1) kg, proportions of carcass as pistola of 467 and 454 (s.e. 2.8) g/kg and pistola meat proportions of 676 and 642 (s.e. 5.1) g/kg, respectively. All fat traits were lower for the C than HF progeny but there was no difference in carcass conformation score. Increasing slaughter weight increased carcass weight (P < 0.001), kidney plus channel fat weight (P < 0.001), and pistola fat proportion(P < 0.001) and decreased the proportions of carcass as pistola (P < 0.05), pistola meat (P < 0.01), and bone (P < 0.05). In conclusion, breed type had no effect on carcass growth but the C progeny had higher meat yield than the HF. Increasing slaughter weight increased fatness and reduced meat yield.
    • Predicting beef carcass meat, fat and bone proportions from carcass conformation and fat scores or hindquarter dissection

      Conroy, S.B.; Drennan, Michael J; McGee, Mark; Keane, Michael G.; Kenny, David A.; Berry, Donagh (Cambridge University Press, 2009-10)
      Equations for predicting the meat, fat and bone proportions in beef carcasses using the European Union carcass classification scores for conformation and fatness, and hindquarter composition were developed and their accuracy was tested using data from 662 cattle. The animals included bulls, steers and heifers, and comprised of Holstein–Friesian, early- and late-maturing breeds x Holstein–Friesian, early-maturing X early-maturing, late-maturing X early-maturing and genotypes with 0.75 or greater late-maturing ancestry. Bulls, heifers and steers were slaughtered at 15, 20 and 24 months of age, respectively. The diet offered before slaughter includes grass silage only, grass or maize silage plus supplementary concentrates, or concentrates offered ad libitum plus 1 kg of roughage dry matter per head daily. Following the slaughter, carcasses were classified mechanically for conformation and fatness (scale 1 to 15), and the right side of each carcass was dissected into meat, fat and bone. Carcass conformation score ranged from 4.7 to 14.4, 5.4 to 10.9 and 2.0 to 12.0 for bulls, heifers and steers, respectively; the corresponding ranges for fat score were 2.7 to 11.5, 3.2 to 11.3 and 2.8 to 13.3. Prediction equations for carcass meat, fat and bone proportions were developed using multiple regression, with carcass conformation and fat score both included as continuous independent variables. In a separate series of analyses, the independent variable in the model was the proportion of the trait under investigation (meat, fat or bone) in the hindquarter. In both analyses, interactions between the independent variables and gender were tested. The predictive ability of the developed equations was assed using cross-validation on all 662 animals. Carcass classification scores accounted for 0.73, 0.67 and 0.71 of the total variation in carcass meat, fat and bone proportions, respectively, across all 662 animals. The corresponding values using hindquarter meat, fat and bone in the model were 0.93, 0.87 and 0.89, respectively. The bias of the prediction equations when applied across all animals was not different from zero, but bias did exist among some of the genotypes of animals present. In conclusion, carcass classification scores and hindquarter composition are accurate and efficient predictors of carcass meat, fat and bone proportions.
    • Prediction of 24-hour milk yield and composition in dairy cows from a single part-day yield and sample

      McParland, Sinead; Coughlan, B.; Enright, B.; O’Keeffe, M.; O’Connor, R.; Feeney, L.; Berry, Donagh; Department of Agriculture, Food and Marine; Science Foundation Ireland; 16/RC/3835 (Teagasc, 2019-08-09)
      Irish Journal of Agricultural and Food Research | Volume 58: Issue 1 Prediction of 24-hour milk yield and composition in dairy cows from a single part-day yield and sample S. McParlandemail , B. Coughlan , B. Enright , M. O’Keeffe , R. O’Connor , L. Feeney and D.P. Berry DOI: https://doi.org/10.2478/ijafr-2019-0007 | Published online: 09 Aug 2019 PDF       Abstract Article PDF References Recommendations Abstract The objective was to evaluate the accuracy of predicting 24-hour milk yield and composition from a single morning (AM) or evening (PM) milk weight and composition. A calibration dataset of 37,481 test-day records with both AM and PM yields and composition was used to generate the prediction equations; equations were validated using 4,644 test-day records. Prediction models were developed within stage of lactation and parity while accounting for the inter-milking time interval. The mean correlation between the predicted 24-hour yields and composition of milk, fat and protein and the respective actual values was 0.97 when based on just an AM milk yield and composition with a mean correlation of 0.95 when based on just a PM milk yield and composition. The regression of predicted 24-hour yield and composition on the respective actual values varied from 0.97 to 1.01 with the exception of 24-hour fat percentage predicted from a PM sample (1.06). A single AM sample is useful to predict 24-hour milk yield and composition when the milking interval is known.
    • Prediction of bovine milk technological traits from mid-infrared spectroscopy analysis in dairy cows

      Visentin, G.; McDermott, A.; McParland, Sinead; Berry, Donagh; Kenny, Owen; Brodkorb, Andre; Fenelon, Mark; de Marchi, M.; European Commission (Elsevier for American Dairy Science Association, 2015-07)
      Rapid, cost-effective monitoring of milk technological traits is a significant challenge for dairy industries specialized in cheese manufacturing. The objective of the present study was to investigate the ability of mid-infrared spectroscopy to predict rennet coagulation time, curd-firming time, curd firmness at 30 and 60 min after rennet addition, heat coagulation time, casein micelle size, and pH in cow milk samples, and to quantify associations between these milk technological traits and conventional milk quality traits. Samples (n = 713) were collected from 605 cows from multiple herds; the samples represented multiple breeds, stages of lactation, parities, and milking times. Reference analyses were undertaken in accordance with standardized methods, and mid-infrared spectra in the range of 900 to 5,000 cm−1 were available for all samples. Prediction models were developed using partial least squares regression, and prediction accuracy was based on both cross and external validation. The proportion of variance explained by the prediction models in external validation was greatest for pH (71%), followed by rennet coagulation time (55%) and milk heat coagulation time (46%). Models to predict curd firmness 60 min from rennet addition and casein micelle size, however, were poor, explaining only 25 and 13%, respectively, of the total variance in each trait within external validation. On average, all prediction models tended to be unbiased. The linear regression coefficient of the reference value on the predicted value varied from 0.17 (casein micelle size regression model) to 0.83 (pH regression model) but all differed from 1. The ratio performance deviation of 1.07 (casein micelle size prediction model) to 1.79 (pH prediction model) for all prediction models in the external validation was <2, suggesting that none of the prediction models could be used for analytical purposes. With the exception of casein micelle size and curd firmness at 60 min after rennet addition, the developed prediction models may be useful as a screening method, because the concordance correlation coefficient ranged from 0.63 (heat coagulation time prediction model) to 0.84 (pH prediction model) in the external validation.
    • Prediction of cull cow carcass characteristics from live weight and body condition score measured pre slaughter

      Minchin, William; Buckley, Frank; Kenny, David A.; Keane, Michael G.; Shalloo, Laurence; O'Donovan, Michael (Teagasc, Oak Park, Carlow, Ireland, 2009)
      A study was conducted to provide information on the degree of carcass finish of Irish cull cows and to investigate the usefulness of live animal measurements for the prediction beef breeds (albeit with a moderate R2 value compared to the carcass weight prediction) using objective, non-intrusive and easily measured live animal measurements, should be of benefit to farmers finishing cull cows in Ireland. of cull cow carcass characteristics. Live weight (LW) and body condition score (BCS) were recorded on cows entering an Irish commercial slaughter facility between September and November, 2005. Data pertaining to sire breed, age and carcass characteristics were collected and subsequently collated for each cow. For analysis, cows (n = 2163) were subdivided into three breed categories: dairy breed sired by Holstein/ Friesian (FR), sired by early-maturing beef breeds (EM) and sired by late-maturing beef breeds (LM). The proportion of cows slaughtered at the desired (TARGET) carcass standard (cold carcass weight ≥ 272 kg, carcass conformation class ≥ P+ and carcass fat class ≥ 3) was low (on average 0.30), but did differ (P < 0.001) between the dairy and beef breed categories (0.22, 0.47 and 0.53 for FR, EM and LM categories, respectively). Regression procedures were used to develop equations to predict cold carcass weight, carcass conformation score, carcass fat score and proportion in the TARGET category from LW and BCS. Equations predicting cold carcass weight had high R2 values for all breed categories (0.81, 0.85 and 0.79 for the FR, EM and LM, respectively). Equations predicting carcass fatness had moderate R2 values for the beef breed categories (0.65 and 0.59 for the EM and LM, respectively). Equations predicting carcass conformation and the TARGET category yielded lower R2 values. The successful prediction of carcass weight for all breed categories and of carcass fatness for the
    • Preface to the special issue of Food and Chemical Toxicology on the outcomes of the MARLON project on veterinary epidemiology of potential health impacts of genetically modified feeds in livestock

      Lawlor, Peadar G; Epstein, Michelle M.; Kleter, Gijs A. (Elsevier, 2018-04-26)
      This special issue is a collection of articles dedicated to the impact of genetically modified (GM) animal feeds on the health of livestock. It features the outcomes of the research project titled “Monitoring of Animals for Feed-related Risks in the Long Term (MARLON)”.
    • Protocols and strategies to study the migration of veterinary drug residues into milk and dairy products in licensed trials

      Power, C.; Sayers, Riona; O'Brien, Bernadette; Furey, A.; Danaher, Martin; Jordan, Kieran (Teagasc (Agriculture and Food Development Authority), Ireland, 2013)
      In the interest of animal welfare, and in order that the results from animal trials are considered valid for inclusion in the development of regulations, it is necessary that such trials are undertaken in accordance with the appropriate licensing arrangements. In January 2013, new licensing arrangements were introduced in the European Union. The aim of this paper is to outline the legislative strategy required for obtaining licences for animal trials and based on live animal trials with flukicides, establishes a blueprint for obtaining the appropriate licences and undertaking the experiments.
    • Protocols and strategies to study the migration of veterinary drug residues into milk and dairy products in licensed trials – Corrigendum

      Power, C.; Sayers, Riona; O'Brien, Bernadette; Furey, A.; Danaher, Martin; Jordan, Kieran (Teagasc (Agriculture and Food Development Authority), Ireland, 2014)
      Corrigendum
    • Purging of inbreeding depression within the Irish Holstein-Friesian population

      McParland, Sinead; Kearney, Francis; Berry, Donagh (Biomed Central, 2009-01-21)
      The objective of this study was to investigate whether inbreeding depression in milk production or fertility performance has been partially purged due to selection within the Irish Holstein-Friesian population. Classical, ancestral (i.e., the inbreeding of an individual's ancestors according to two different formulae) and new inbreeding coefficients (i.e., part of the classical inbreeding coefficient that is not accounted for by ancestral inbreeding) were computed for all animals. The effect of each coefficient on 305-day milk, fat and protein yield as well as calving interval, age at first calving and survival to second lactation was investigated. Ancestral inbreeding accounting for all common ancestors in the pedigree had a positive effect on 305-day milk and protein yield, increasing yields by 4.85 kg and 0.12 kg, respectively. However, ancestral inbreeding accounting only for those common ancestors, which contribute to the classical inbreeding coefficient had a negative effect on all milk production traits decreasing 305-day milk, fat and protein yields by -8.85 kg, -0.53 kg and -0.33 kg, respectively. Classical, ancestral and new inbreeding generally had a detrimental effect on fertility and survival traits. From this study, it appears that Irish Holstein-Friesians have purged some of their genetic load for milk production through many years of selection based on production alone, while fertility, which has been less intensely selected for in the population demonstrates no evidence of purging.
    • Quantification of nutrient supply in forage-based diets for beef cattle

      McGee, Mark; Owens, David; O'Kiely, Padraig; Teagasc Walsh Fellowship Programme (Teagasc, 2009-12-01)
      Introduction Cattle rearing systems in Ireland are predominantly grass-based as 80% of agricultural land is dedicated to grassland (silage, hay and pasture) (CSO, 2007). Feed costs represent the largest single variable cost in beef production in Ireland. Grazed grass is generally the cheapest source of food available for beef (and milk) production provided that the environment and management permit high yields of high quality herbage to be utilised (McGee, 2000). Environmental legislation and the rules of environmental schemes such as the European Union (EU) Rural Environmental Protection Scheme are progressively restricting the application of fertilizer Nitrogen (N), and many grazing systems are becoming more extensive. Over 80% of all farms in Ireland make grass silage (O’Kiely et al., 1998) and it accounts for 87% of total grass conserved (Mayne and O’Kiely, 2005). The deficiencies in nutrient supply to beef cattle from grass silage are usually overcome by supplementing with concentrates (McGee, 2005), which are primarily cereal-based (Drennan et al., 2006). However, diverse types of concentrates containing a variety of feed ingredients, particularly non-cereal by-products are available and frequently fed as supplements to grass silage or as highconcentrate diets. The relatively small amount of information available on feeding these contrasting concentrates to beef cattle is inconsistent. Moreover, there has been an increased use of other ensiled forages such as maize and whole-crop cereals. These forages have high intake potential and can reduce the concentrate feeding level, while maintaining or increasing performance of beef cattle (Keady, 2005). With increasing costs of beef production and increasing constraints of environmental regulations, efficient utilisation of consumed nutrients by cattle is imperative in providing sustainable production and income to farmers. Feed evaluation systems are used to match the dietary nutrient supply with animal requirements for a specific level of production (Dijkstra et al., 2007). These systems are important in order to optimise the efficiency of feed utilisation, to improve animal performance and to reduce nutrient losses to the environment (Dijkstra et al., 2007). Although the reticulo-rumen is central to the profile of nutrients available for absorption, yet quantitative knowledge of the rates of passage and the digestion of nutrients in the rumen is limited compared with that on degradation rates (Dijkstra et al., 2007). There is a lack of information that adequately characterises the supply of nutrients from forages and feedstuffs specific to Ireland, especially for fresh grass-based diets of which, there are very few studies reported in the literature. This shortcoming impedes our ability to capitalise on the merits of evolving feeding systems. This project aimed to: 1. Increase the knowledge and advance the understanding on rumen digestion and nutrient flow from the rumen of the main forages / forage-based diets offered to beef cattle in Ireland. 2. Evaluate strategies for optimal utilization of nutrients consumed by cattle.
    • Ranking of Sire Breeds and Beef Cross Breeding of Dairy and Beef Cows

      Keane, Michael G. (Teagasc, 2011-03-01)
      Summary There is general agreement across countries on the ranking of beef breeds for production and carcass traits. Differences between dairy and early maturing beef breeds in growth and slaughter traits are small, but the latter have lower feed intake and better carcass conformation. Late maturing beef breeds also have lower feed intake and better carcass conformation and in addition, have a higher growth rate, kill-out proportion and carcass muscle proportion. When factors such as age and fatness are accounted for, differences between breeds in meat quality traits are small. Differences amongst breed types in kill-out proportion can be explained by differences in gut contents (consequent on differences in feed intake), differences in the proportions of gastrointestinal tract and metabolic organs, differences in hide proportion, and differences in offal fats. Growth is an allometric, rather than an isometric, process. Some parts, organs and tissues grow relatively more slowly than the animal overall, and so become decreasing proportions over time, while others grow relatively faster and become increasing proportions. With increasing slaughter weight, the proportions of non carcass parts, hind quarter, bone, total muscle and higher value muscle decrease, while the proportions of non carcass and carcass fats, fore quarter and marbling fat all increase. Because of heterosis or hybrid vigour, the productivity of cross-bred cattle is superior to the mean of the parent breeds. While calving difficulty may be slightly higher (probably due to greater birth weight), calf mortality is much reduced in cross-breds. In addition, general robustness and growth rate are increased. There are additive effects of heterosis in the dam and the progeny. When cross-bred cows are mated to a bull of a third breed, >60 % of total heterosis is attributable to the cross-bred cows. The double muscling phenotype in beef cattle is due to the inactivated myostatin gene, but the inactivating mutation is not the same in all breeds and other genes also contribute to muscling. Compared to normal animals, double muscled animals have lower proportions of digestive tract, internal fats and metabolic organs. This explains their superior kill-out proportion. They also have a smaller hind shin that helps accentuate the muscling in the remainder of the 4 limb. There are similar degrees of muscular hypertrophy in both the hind and fore quarters. Muscle to bone ratio is about one third greater in double muscled than in normal carcasses. Piedmontese cattle with none, one or two mutated myostatin alleles were compared with normal Herefords and Limousins. In the absence of any mutated allele, Piedmontese were similar to Herefords, with one mutated allele they were similar to Limousins and with two mutated alleles they were immensely superior to Limousins. In fact, the response to the second mutated allele was about three times that to the first. If progeny approximated to the mean of the parent breeds, crossing a double muscled sire with a dairy or early maturing beef cow would result in cattle of similar characteristics to pure-bred late maturing beef breeds. This does not happen because double muscling is dependent on a homozygous myostatin genotype. The progeny of a common cow breed and normal late maturing, or double muscled, sire breeds have similar production traits.
    • The relationship between various live animal scores/measurements and carcass classification for conformation and fatness with meat yield and distribution, and ultimate carcass value

      Drennan, Michael J; McGee, Mark; Conroy, S.B.; Keane, Michael G.; Kenny, David A.; Berry, Donagh (Teagasc, 2009-12-01)
      Accordingly, the primary objectives of the following study were to: (1) determine the relationship of live animal muscular and skeletal scores, ultrasonically scanned muscle and fat depth measurements of the m. longissimus dorsi, and carcass conformation and fat scores with kill-out proportion, carcass composition and value. (2) Specifically develop and test the accuracy of prediction equations for carcass meat, fat and bone proportions, derived from carcass conformation and fat scores, and develop prediction equations for total carcass composition from hind-quarter composition.
    • Relative Tissue Growth Patterns and Carcass Composition in Beef Cattle

      Keane, Michael G. (Teagasc, 2011-03-01)
      Summary The main objective of the beef breed evaluation programme carried out at Grange Beef Research Centre was to compare the productive characteristics of different beef breed crosses out of Holstein-Friesian cows. In the course of this work much additional information was acquired, particularly on growth patterns of body organs and tissues, and how these affect kill-out proportion and carcass composition. The data were also used to examine relationships between carcass classification variables and carcass composition. Cattle used for beef production in Ireland can be classified into three main biological types: (i) early maturing, (ii) dairy, and (iii) late maturing. Results from an experiment that compared Friesians (dairy), Hereford × Friesians (early maturing) and Charolais × Friesians (late maturing) are used to represent these biological types. The material is organized under the following headings: (i) non carcass parts and kill-out proportion, (ii) carcass composition, (iii) carcass tissue distribution, (iv) muscle chemical composition, (v) gender, (vi) dairy breeds, and (vii)carcass classification and composition. Kill-out proportion increased by about 10 g/kg from Friesians to Hereford × Friesians to Charolais × Friesians. It also increased by about 10 g/kg per 100 kg increase in slaughter weight. Friesians had higher proportions of gastrointestinal tract plus contents than the two beef crosses and also had higher proportions of metabolic organs. Hereford crosses had a higher proportion of hide and offal fats than Charolais crosses. At any carcass weight, early maturing animals had more fat and less bone and muscle than late maturing animals. As carcass weight increased, the proportions of bone and muscle in the carcass decreased, and the proportion of fat increased, but the rates of these changes differed with biological type. Carcass muscle distribution also differed with biological type. Late maturing cattle had a higher proportion of hind quarter and higher value muscle than Friesians and early maturing animals, while Friesians had higher proportions than early maturing animals. Muscle lipid content (marbling) differed with biological type (early maturing > dairy > late maturing) and with carcass joint (highest for flank and ribs, lowest for m. longissimus). Early maturing steers and heifers had similar carcass fat proportions when the heifers were about 60 kg carcass lighter than the steers. Despite having poorer carcass conformation, heifers had a slightly higher proportion of muscle and a considerably higher proportion of higher value muscle than steers. Carcass classification grade was not a reliable indicator of carcass muscle proportion. Carcass fat class was related to both carcass fat and muscle proportions but accounted for less than half the variance in these. Carcass conformation class was not related to carcass fat proportion, carcass muscle proportion or higher value muscle proportion, but it was negatively related to carcass bone proportion.
    • Residual feed intake phenotype and gender affect the expression of key genes of the lipogenesis pathway in subcutaneous adipose tissue of beef cattle

      McKenna, Clare; Porter, Richard K.; Keogh, Kate; Waters, Sinead M.; McGee, Mark; Kenny, David A.; Teagasc Walsh Fellowship Programme; RMIS: 6092 (Springer Science and Business Media LLC, 2018-09-20)
      Background Feed accounts for up to 75% of costs in beef production systems, thus any improvement in feed efficiency (FE) will benefit the profitability of this enterprise. Residual feed intake (RFI) is a measure of FE that is independent of level of production. Adipose tissue (AT) is a major endocrine organ and the primary metabolic energy reservoir. It modulates a variety of processes related to FE such as lipid metabolism and glucose homeostasis and thus measures of inter-animal variation in adiposity are frequently included in the calculation of the RFI index. The aim of this study was to determine the effect of phenotypic RFI status and gender on the expression of key candidate genes related to processes involved in energy metabolism within AT. Dry matter intake (DMI) and average daily gain (ADG) were measured over a period of 70 d for 52 purebred Simmental heifers (n = 24) and bulls (n = 28) with an initial BW±SD of 372±39.6 kg and 387±50.6 kg, respectively. Residual feed intake was calculated and animals were ranked within gender by RFI into high (inefficient; n = 9 heifers and n = 8 bulls) and low (efficient; n = 9 heifers and n = 8 bulls) groups. Results Average daily gain ±SD and daily DMI ±SD for heifers and bulls were 1.2±0.4 kg and 9.1±0.5 kg, and 1.8±0.3 kg and 9.5±1 kg respectively. High RFI heifers and bulls consumed 10% and 15% more (P < 0.05) than their low RFI counterparts, respectively. Heifers had a higher expression of all genes measured than bulls (P < 0.05). A gender × RFI interaction was detected for HMGCS2(P < 0.05) in which high RFI bulls tended to have lower expression of HMGCS2 than low RFI bulls (P < 0.1), whereas high RFI heifers had higher expression than low RFI heifers (P < 0.05) and high RFI bulls (P < 0.05). SLC2A4 expression was consistently higher in subcutaneous AT of low RFI animals across gender. Conclusion The findings of this study indicate that low RFI cattle exhibit upregulation of the molecular mechanisms governing glucose metabolism in adipose tissue, in particular, glucose clearance. The decreased expression of SLC2A4 in the inefficient cattle may result in less efficient glucose metabolism in these animals. We conclude that SLC2A4 may be a potential biomarker for RFI in cattle.