• 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 P. (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 bovine milk technological traits from mid-infrared spectroscopy analysis in dairy cows

      Visentin, G.; McDermott, A.; McParland, Sinead; Berry, Donagh P.; Kenny, Owen; Brodkorb, Andre; Fenelon, Mark A.; 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)”.
    • Presentations from the All Island Farm Safety Conference

      Gracey, Kenny; Meredith, David; McNamara, John; Dalton, Marie; Murray, Finian; Earley, Bernadette; Prendiville, Daniel J.; Mazurek, Mickael; McNamara, John; Kennedy, Michael; et al. (Teagasc, 18/06/2008)
      An All Island Farm Safety Conference took place on Wednesday, 18 June 2008 at the Hillgrove Hotel, Old Armagh Road, Monaghan. The presentations from this conference will be of interest to farmers, agricultural contractors, and anyone with an interest in safety and health in agriculture. The presentations from this conference will be of interest to farmers, agricultural contractors, and anyone with an interest in safety and health in agriculture. Each of the talk titles below is a link to the Microsoft PowerPoint presentation in PDF format
    • Prevalence of antibodies to Leptospira interrogans serovar hardjo in bulk tank milk from unvaccinated irish dairy herds

      Leonard, Nola; Mee, John F; Snijders, Sylvia M. E.; Mackie, Dermot (Biomed Central, 2004-04-01)
      Bulk tank milk samples, collected from 347 herds throughout the Republic of Ireland using a sampling frame based on seven milk-recording organisations, were tested by ELISA for antibodies to Leptospira interrogans serovar hardjo. These herds, which had not been vaccinated against leptospirosis within the previous five years, were categorised according to their province, milk-recording organisation and size. Two-hundred-and-seventy-three herds (79%) had a positive ELISA titre. Both the probability of a herd being seropositive and the antibody level in the herd milk sample were affected by the province (P < 0.05 and P < 0.01, respectively) and the herd size category (P < 0.05 and P < 0.01, respectively). Larger herds were significantly more likely to have positive reactions and higher mean concentrations of antibody. It was concluded that a high proportion of unvaccinated Irish dairy herds have been exposed to infection with Leptospira hardjo.
    • Prevalence of BoHV-1 seropositive and BVD virus positive bulls on Irish dairy farms and associations between bull purchase and herd status

      Martinez-Ibeas, Ana M; Power, C.; McClure, Jennifer; Sayers, Riona (Biomed Central, 2015-12-09)
      Background BVD and IBR are contagious viral diseases highly prevalent in Irish cattle. Despite their significant reproductive and economic impact very little is known about the BVD and IBR status of stock bulls (a bull used for breeding purposes). There are still a high proportion of dairy farms in Ireland that rely on the use of a bull for breeding cattle and ensuring the fertility of the bulls is of paramount importance for the efficiency of the farms. The prevalence of BoHV-1 and BVD in stock bulls in Irish dairy herds has never been investigated. The objectives of this study therefore were: (i) to provide descriptive, observational data on the use of stock bulls on Irish dairy farms; (ii) to investigate the BVD and BoHV1 status of a sub-set of stock bulls; (iii) to investigate factors associated with BVD and BoHV1 status of stock bulls and (iv) to investigate factors associated with dairy herd status for BVD and BoHV1, including any associations with the use of stock bull. A total of 529 blood samples from bulls involved in the dairy breeding process were analysed for BVD virus using RT-PCR, and BoHV-1 antibodies by ELISA test. A total of 305 different dairy herds took part in the study and the overall BVD and BoHV-1 herd status was determined by ELISA using four bulk tank milk samples over the 2009 lactation. Logistic regression was used to investigate the associations between the stock bulls and BVD and BoHV-1 herd and individual status. Results Of the 305 total participating farms, 235 farms (77 %) had at least one bull and 167 farms had purchased bulls. Two bulls (0.4 %) out of 529 tested were found positive for BVD virus and 87 (16.7 %) tested seropositive for BoHV-1. Some significant associations were identified between the purchase of bulls and both viral diseases. Purchased bulls were three times more likely to be seropositive for BoHV-1 than homebred bulls. In the same way, herds with purchased bulls were three times more likely to be classified as seropositive for BVD and four times more likely to have evidence of recent BoHV-1 circulation than farms where all the bulls were homebred. Conclusions The prevalence of BoHV-1 and BVD in stock bulls in Irish dairy herds has never been investigated. This study highlights the widespread use of stock bulls in Irish dairy herds, as well as the high rate of exchange of bulls between farms. Significant associations were found between the origin of the bull and their serological BoHV-1 status. In keeping with these results, bulls with higher number movements between farms were more likely to be seropositive for BoHV-1.
    • Prevalence of exposure to bovine viral diarrhoea virus (BVDV) and bovine herpesvirus-1 (BoHV-1) in Irish dairy herds

      Sayers, Riona; Byrne, Nicky; O'Doherty, Eugene; Arkins, S.; Irish Dairy Levy Fund (Elsevier, 2015-03-05)
      Bovine viral diarrhoea virus (BVDV) and bovine herpesvirus 1 (BoHV-1) are contagious bovine viral agents. The objectives of this study were to use quarterly bulk milk and ‘spot’ testing of unvaccinated youngstock to establish the national prevalence of exposure to BVDV and/or BoHV-1 in Irish dairy herds. Seasonality of bulk milk ELISA results was also examined. From a geographically representative population of 305 dairy herds, 88% and 80% of herds yielded mean annual positive bulk milk readings for BVDV and BoHV-1, respectively. Of these, 61% were vaccinated against BVDV and 12% against BoHV-1. A total of 2171 serum samples from weanlings having a mean age of 291 days yielded 543 (25%) seropositive for BVDV, and 117 (5.4%) seropositive for BoHV-1. A significant seasonal trend in bulk milk antibody ELISA readings and herd status was recorded for BVDV, with more herds categorised as positive in the latter half of the year.
    • Prevalence of welfare outcomes in the weaner and finisher stages of the production cycle on 31 Irish pig farms

      van Staaveren, Nienke; Calderón Díaz, Julia A.; Manzanilla, Edgar G; Hanlon, A.; Boyle, Laura; Department of Agriculture, Food and the Marine, Ireland; 11/S/107 (Biomed Central, 2018-03-27)
      Background Knowledge on the most prevalent welfare problems for pigs in different production stages is required to improve herd management plans. Thirty-one farrow-to-finish pig farms were visited between July and November 2015 to assess the welfare of pigs using the multicriteria approach of the Welfare Quality® protocol. On each farm, 6 pens were selected using proportionate stratified sampling in the first weaner (S1, 4 to 8 wks), second weaner (S2, 8 to 13 wks) and finisher stage (S3, 13 to 23 wks), excluding hospital pens. Each pen was observed for 10 min and the number of pigs affected by different welfare outcomes was recorded. The percentage of pigs affected was calculated and ranked to identify the most prevalent outcomes within each production stage. Differences between production stages were analysed using generalised linear mixed models for binomial data with pen within stage and farm as a random effect. Results Tail and ear lesions showed the highest prevalence; however, large variation was observed between farms. In S1 the most prevalent welfare outcomes (presented as median prevalence) were poor body condition (4.4%), lethargic pigs (1.5%), scouring (20.3% of pens) and huddling (3.7%). In S2 and S3 outcomes related to injurious behaviour (tail lesions: 5.9% [S2] and 10.5% [S3], ear lesions: 9.1% [S2] and 3.3% [S3], and flank lesions: 0.4% [S2] and 1.3% [S3]), lameness (0.8% [S2] and 1.1% [S3]), bursitis (3.9% [S2] and 7.5% [S3]) and hernias (1.6% [S2] and 1.8% [S3]) were more prevalent. Conclusions A large variation was observed for the recorded welfare outcomes corresponding to the different challenges pigs experience during the different stages of production on commercial pig farms. The prevalence of pigs affected by lesions caused by injurious behavior is a cause for concern and requires a collaborative approach to identify appropriate intervention strategies. This information could be used to further investigate appropriate benchmark values for different welfare outcomes that would assist the pig industry to develop appropriate health and welfare management plans to minimise welfare problems. At herd level such plans should include information on aspects of intervention, treatment, and the management of hospital pens as well as euthanasia.
    • Prevalence of, and risk factors associated with, perinatal calf mortality in pasture-based Holstein-Friesian cows

      Mee, John F; Berry, Donagh P.; Cromie, A. R. (Cambridge University Press, 2008-04)
      Recent publications indicate that the prevalence of perinatal mortality has increased in some dairy industries and an increased proportion of this loss is not associated with the traditional risk factors for perinatal mortality. The objectives of this study were to establish the prevalence of perinatal mortality (calf death within 24 h of calving) in Irish dairy herds and to determine the current significance of putative risk factors in pasture-based management systems. A total of 182 026 records of full-term calvings from Holstein-Friesian dams served by artificial insemination (AI) sires of seven breeds in herds of 20 calvings or more per year were available from the Irish national breeding database over 4 years (2002 to 2005). The prevalence of perinatal mortality was 4.29% (7.7% in primiparae and 3.5% in pluriparae). The likelihood of perinatal mortality increased between 2002 and 2005 and was greatest in June and in winter. There was an interaction (P < 0.001) between the effect of calving assistance and parity with the effect of dystocia on perinatal mortality being greater in primiparae. The odds of perinatal mortality were greater in male (OR = 1.12; P < 0.001) and in twin calves (OR = 5.70-13.36; P < 0.001) and in dams that had perinatal mortality at the previous calving (OR = 4.21; P < 0.001). The logit of the probability of perinatal mortality increased by 0.099 per unit increase in sire predicted transmitting ability (PTA) for direct perinatal mortality. The probability of perinatal mortality increased at an increasing rate in primiparae as animals calved at a younger age relative to the median age at first calving. The only herd-level factor examined, herd size did not affect the odds of perinatal mortality. These data indicate that the prevalence of perinatal mortality in this cattle population is similar to that in other pasture-based dairy systems worldwide. The putative exposures and attributes traditionally associated with perinatal mortality were associated with perinatal mortality in this pasture-based dairy cow population. The practical implication of these results is that as many of the significant risk factors are largely not under management control (year of calving, month of calving, twin calving, primiparity, previous perinatal mortality and foetal gender), herd owners must focus on the significant determinants under their control (age at first calving, sire genetic merit for direct perinatal mortality and both the extent of calving supervision and the degree of assistance), in order to reduce the prevalence of perinatal mortality and improve perinatal welfare.
    • Production and carcass traits of high dairy genetic merit Holstein, standard dairy genetic merit Friesian and Charolais × Holstein-Friesian male cattle

      McGee, Mark; Keane, Michael G.; Neilan, R.; Moloney, Aidan P; Caffrey, Patrick J. (Teagasc (Agriculture and Food Development Authority), Ireland, 2005)
      The increased proportion of Holstein genetic material in the dairy herd has consequences for beef production in Ireland. A total of 72 spring-born male calves (24 Holsteins (HO), 24 Friesian (FR) and 24 Charolais × Holstein-Friesians (CH)) were reared from calfhood to slaughter. Calves were artificially reared indoors and spent their first summer at pasture following which they were assigned, on a breed basis, to a factorial combination of two production systems (intensive 19-month bull beef and extensive 25-month steer beef) and two slaughter weights (560 and 650 kg). After slaughter the pistola hind quarter was separated into fat, bone and muscle. Live-weight gain, carcass gain, kill-out proportion, carcass conformation and carcass fat scores were 830, 811 and 859 (s.e. 14.9) g/day, 540, 533, 585 (s.e. 7.7) g/day, 526, 538 and 561 (s.e. 3.0) g/kg, 1.51, 2.18 and 2.96 (s.e. 0.085), and 3.40, 4.25 and 4.06 (s.e. 0.104) for HO, FR and CH, respectively. Corresponding values for pistola weight as a proportion of carcass weight, pistola muscle proportion and pistola fat proportion were 458, 459 and 461 (s.e. 2.6) g/kg, 657, 645 and 667 (s.e. 3.7) g/kg, and 132, 161 and 145 (s.e. 4.1) g/kg. Compared with the intensive system, animals on the extensive system had a lower (P < 0.001) daily live-weight gain, kill-out proportion and a lower muscle proportion in the pistola. Increasing slaughter weight increased (P < 0.001) carcass weight and carcass fat score and reduced the proportion of muscle in the pistola. Allometric regression coefficients for pistola weight on side weight, and total bone, muscle and fat weights on pistola weight were 0.898, 0.755, 0.900 and 1.910 respectively. It is concluded that HO grew at least as fast as FR but had a lower killout proportion. Carcass conformation and fat scores were greater for FR than for HO and muscle proportion in the pistola was lower and total fat proportion was higher. Compared with FR, CH had heavier carcasses, a higher kill-out proportion and less fat and more muscle in the pistola.
    • 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 P. (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.
    • Quantitative analysis of ruminal methanogenic microbial populations in beef cattle divergent in phenotypic residual feed intake (RFI) offered contrasting diets

      Carberry, Ciara A; Kenny, David A.; Kelly, Alan K; Waters, Sinead M.; Department of Agriculture, Food and the Marine; RSF 05 224 (Biomed Central, 2014-08-22)
      Background Methane (CH4) emissions in cattle are an undesirable end product of rumen methanogenic fermentative activity as they are associated not only with negative environmental impacts but also with reduced host feed efficiency. The aim of this study was to quantify total and specific rumen microbial methanogenic populations in beef cattle divergently selected for residual feed intake (RFI) while offered (i) a low energy high forage (HF) diet followed by (ii) a high energy low forage (LF) diet. Ruminal fluid was collected from 14 high (H) and 14 low (L) RFI animals across both dietary periods. Quantitative real time PCR (qRT-PCR) analysis was conducted to quantify the abundance of total and specific rumen methanogenic microbes. Spearman correlation analysis was used to investigate the association between the relative abundance of methanogens and animal performance, rumen fermentation variables and diet digestibility. Results Abundance of methanogens, did not differ between RFI phenotypes. However, relative abundance of total and specific methanogen species was affected (P < 0.05) by diet type, with greater abundance observed while animals were offered the LF compared to the HF diet. Conclusions These findings suggest that differences in abundance of specific rumen methanogen species may not contribute to variation in CH4 emissions between efficient and inefficient animals, however dietary manipulation can influence the abundance of total and specific methanogen species.
    • 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.
    • Rearing calves outdoors with and without calf jackets compared with indoor housing on calf health and live-weight performance

      Earley, Bernadette; Murray, Margaret; Farrell, J.A.; Nolan, Marie-Jean; National Development Plan, 2000-2006 (Teagasc (Agriculture and Food Development Authority), Ireland, 2004)
      The objective of this study was to compare the effects of rearing calves outdoors, with and without all-weather calf jackets, with calves reared indoors on calf immunity and animal performance. In February 1999, male Holstein calves (mean (s.e.) weight 55 (1.90) kg) were randomly assigned to one of three treatments (n=30 per treatment): 1) outdoors with jacket, (J; mean age 19 (s.e. 2.0) days); 2) outdoors without jacket (NJ; mean age 19 (s.e. 1.8) days), and 3) indoors on straw (I; mean age 19 (s.e. 1.0) days). Calves received an individual allowance of 25 kg of milk replacer dry matter during the first 42 days with ad libitum access to a concentrate ration from day 0 to 63. The jackets were removed from the calves on day 42. Live-weight gain from day 0 to day 63 of the study was not significantly different between treatments (J, 0.79; NJ, 0.80; I, 0.80 kg). Sixty percent of the J calves and 53% of the NJ calves required four or more antibiotic treatments for respiratory disease while corresponding treatments were required for 97% of the I calves. The incidence of diarrhoea was significantly higher in both outdoor treatments compared to the I treatment. There was no significant difference in white blood cell counts or in serum immunoglobulin concentrations between treatments on days 0, 21, 42 and 63 or in in vitro interferon-γ production on day 63. It is concluded that using calf jackets on calves reared outdoors had no beneficial effect on calf performance or immune status. The incidence of respiratory disease was higher and diarrhoea incidence was lower in calves reared indoors compared with calves reared outdoors. There was no significant difference in incidences of diarrhoea and respiratory disease between the two outdoor treatments.
    • Rearing Undocked Pigs on Fully Slatted Floors Using Multiple Types and Variations of Enrichment

      Chou, Jen-Yun; Drique, Constance; Sandercock, Dale; D'Eath, Rick; O'Driscoll, Keelin (MDPI AG, 2019-04-02)
      In fully slatted systems, tail biting is difficult to manage when pigs’ tails are not docked because loose enrichment material can obstruct slurry systems. This pilot study sought to determine: a) whether intact-tailed pigs can be reared with a manageable level of tail biting by using multiple slat-compatible enrichment; b) whether a variation of enrichment has an effect; and c) whether pigs show a preference in enrichment use. Ninety-six undocked pigs were given the same enrichment items from one week after birth until weaning. At weaning, four different combinations of 8 enrichment items were utilized based on predefined characteristics. These were randomly assigned to 8 pens (n = 12 pigs/pen). Four pens had the same combination (SAME) from assignment and four pens switched combinations every two weeks (SWITCH). Individual lesion scores, interactions with the enrichment, and harmful behaviours were recorded. The average tail score during the experiment was low (0.93 ± 0.02). Only one pig in a SAME pen had a severely bitten tail (partly amputated). The overall level of interaction with enrichment did not decline over time. Pigs interacted with a rack of loose material most frequently (p < 0.001). The study showed promising results for rearing undocked pigs on fully slatted floors using slat-compatible enrichment.
    • The relationship between anogenital distance and fertility, and genome-wide associations for anogenital distance in Irish Holstein-Friesian cows

      Gobikrushanth, M.; Purfield, Deirdre C; Kenneally, J.; Doyle, R.C.; Holden, Shauna A.; Martinez, P.M.; Rojas Canadas, E.; Bruinjé, Tony C.; Colazo, M.G.; Ambrose, D. J.; et al. (Elsevier, 2018-12-26)
      The evaluation of anogenital distance (AGD), the distance from the center of the anus to base of the clitoris, as a potential fertility trait for genetic selection in dairy cows has generated recent interest. The objectives of this cross-sectional observational study were to (1) characterize the distribution and variability of AGD, (2) determine factors associated with AGD, (3) estimate heritability for AGD, (4) identify single nucleotide polymorphisms (SNP) associated with phenotypic variation of AGD, and (5) validate the relationship between categories of AGD and fertility in Irish Holstein-Friesian cows. Anogenital distance was measured using digital calipers in 1,180 Holstein cows (mean ± standard deviation: 225 ± 79 d in milk) from 10 dairy herds located in Munster, Ireland. In addition, age (yr), weight (kg), height at hip (cm), and body condition score (BCS) at the time of AGD measurement were determined in a subset of 281 cows. Genotype information available from 908 cows was subsequently imputed to the Illumina Bovine High Density BeadChip (Illumina Inc., San Diego, CA) for genome-wide association analysis of phenotypic variation in AGD. Overall, AGD had a normal distribution and high variability (mean ± standard deviation; 119.2 ± 11.6 mm). Anogenital distance was weakly but positively associated with cow age, hip height, and body weight, and negatively associated with BCS; the phenotypic variation in AGD that was explainable by these variables was small (coefficient of determination; R2 = 0.09, 0.06, 0.10, and 0.02, respectively). The estimated heritability for AGD was 0.37 (standard error of mean ± 0.08). Six SNP of suggestive significance were identified on Bos taurus autosomes 6, 15, 20, and 26; however, none of these SNP was related to previously identified candidate genes for fertility. Cows were categorized into quartiles (Q1; 86 to 111 mm; n = 311, Q2; 112 to 120 mm; n = 330; Q3; 121 to 127 mm; n = 265, and Q4; 128 to 160 mm; n = 274) based on AGD and the association with reproductive outcomes examined (21-d submission rate, pregnancy to first AI, pregnancy rate within 21, 42 and 84-d after the farm mating start date, and number of times bred). None of the reproductive variables differed significantly between AGD categories. In summary, despite identification of high variability and moderate heritability for AGD in Irish Holstein-Friesian cows, reproductive outcomes did not differ between categories of AGD. This latter result differs from our previous finding of an inverse relationship between AGD and pregnancy outcomes in first- and second-parity Canadian Holstein cows, emphasizing the need to test and validate this new phenotype in diverse cow populations.