• Calf Health and Immunity.

      Earley, Bernadette; Fallon, Richard J. (Teagasc, 1999-11-01)
      Suckled calves had significantly higher serum IgG 1 concentrations than mart purchased dairy calves. The marked differences in immunoglobulin levels between suckled calves and dairy calves suggest that these calves received either insufficient quality or quantity of colostral immunoglobulins. Factors affecting calf serum Ig concentrations are, Ig concentration in colostrum, colostrum intake, Ig mass, calf age at first feeding, nutrition of the dam, method of ingestion, presence of the dam, age of the dam and the calf. When suckled calves were fed a similar volume of colostrum relative to birth weight (40 ml/kg) and at the same time interval post birth, there was no significant difference across the three suckler herd progeny for IgG1, IgA and IgM and total Ig serum levels at 28 and 56 days of age. However, serum IgG2 levels were significantly lower in the Limousin x beef breed when compared with the Charolais x beef breed suckled calves at 28 days of age. Healthy calves had higher serum immunoglobulins (IgG1) than calves treated for respiratory disease, enteric disease or for both respiratory disease and enteric disease. It is well recognised that immunoglobulins are absorbed from the intestine for only a short period post birth and that efficiency of absorption is dependent on ensuring that the calf receives adequate colostrum in the immediate post-partum period. Low serum IgG1 concentrations are attributable to failures to obtain adequate colostral immunoglobulins in the period immediately following birth. The mean IgA and IgM serum levels of suckled calves in the present study were only slightly higher than dairy calves while IgG1 serum levels were almost approximately twice as high. Feeding colostrum high in Ig results in higher calf serum Ig concentrations at 48h. The low serum Ig levels reported in the present study suggest that dairy calves failed to obtain adequate transfer of colostral immunoglobulins. Calves with a lower immune status are more susceptible to neonatal infection and thus the importance of colostrum in the immediate post partum period cannot be overemphasised. Thus, the identification of calves with low levels of immunity might stimulate calf producers to ensure that calves receive adequate levels of colostral immunoglobulins. The implications of the present findings are that compared with suckled calves, dairy calves are not receiving 1). adequate quantity of colostrum 2). adequate quality of colostrum. 3). Colostrum soon enough post birth 4). or a combination of all of the previous factors. Rearing calves outdoors using calf jackets had no beneficial effect on calf performance. The incidence of respiratory disease was higher in calves reared indoor when compared with calves reared outdoor with and without jackets. There was an increased incidence of diarrhoea in calves reared outdoors irrespective of calf jacket. Lymphocytes from calves with respiratory disease manifest an impaired capability to blast in vitro. Chromium (Cr) supplementation (250 mg/kg dry matter intake) enhanced the blastogenic response in healthy calves, while, calves with respiratory had impaired blastogenic responses. Supplementation with organic Cr (250 mg/kg dry matter intake) for 63 days had no major effect on physiological parameters and had select effects on haematological parameters, namely, the % monocytes. The % monocytes were significantly higher in the standard commercial milk replacer (CMR) (Skim) Cr supplemented calves when compared with the whey based (CMR) + Soya Brand B or whey based CMR + Soya Brand C or whey based enzyme processed soya Brand C + Cr treatment groups.
    • Cattle Embryo Growth Development and Viabilty.

      Morris, Dermot G.; Grealy, M.; Leese, H.J.; Diskin, Michael G.; Sreenan, J.M. (Teagasc, 2001-06-01)
      A major problem for the cattle breeding industry is the high rate of early embryo loss which compromises reproductive efficiency and genetic improvement, resulting in serious financial loss to farmers. An important part of the Teagasc research programme in this area is the investigation of basic parameters of cattle embryo growth, development and viability during the critical period when most of the embryo loss occurs. We have now characterised this period of embryo development and to our knowledge, this is the first report describing the morphology, growth rate, protein content and metabolic activity of cattle embryos during this period. The main results are summarised here and detailed results have been published in the papers listed at the end of this report. Embryo growth rate and protein content increased exponentially between days 8 and 13 after fertilisation. Furthermore, there was a high rate of protein synthetic activity, energy and amino acid metabolism and signal transduction activity, all reaching a peak between days 8 and 13 after fertilisation. Because of the high rate of metabolic activity evident during this time it is likely that the embryos are very susceptible to environmental changes that have the potential to interfere with normal developmental mechanisms. The results arising from this project suggest that the critical period of early embryo loss in cattle may now be narrowed to a time window of day 8 to 13 rather than day 8 to 16 as presumed up to now. The main results are summarised.
    • A Census Atlas of Irish Agriculture

      Commins, Patrick; Lafferty, F.; Walsh, Jim A. (Teagasc, 1999-08-01)
      Computerised mapping systems were developed to analyse agricultural census statistics and data from agricultural policy administration sources. The objective was to identify local geographical variations in the structure and trends in the agricultural economy by mapping the available information, principally at the level of the District Electoral Division (DED) and the Rural District (RD). There were 3,113 DEDs and 156 RDs in the analysis. The main database was the 1991 Census of Agriculture, the latest available. Some statistics are updated annually and where possible these were used in tabular form to trace the 1991- 1997 trends for Regional Authority areas. Conclusions: There are distinctive farming regions in the country whose boundaries span unevenly across county limits. These are undergoing different processes of change depending on their resource base, their responses to economic imperatives, and the policy environment. • Commercial farming has become increasingly associated with areas south and east of a line from Limerick to Dundalk. • It is likely that policies and trends post 2000 will further increase the differences in resource use between commercial farming and other areas.
    • Characterisation of feedstuffs for ruminants.

      Moloney, Aidan P; Woods, V.B.; O'Mara, Frank P. (Teagasc, 2001-05-01)
      A wide variety of feed ingredients are used in the manufacture of compound feeds in Ireland. Unprocessed feedstuffs vary from batch to batch due to differences caused by variety, soils, weather, etc. By -product feeds may also vary due to the processes from which they were produced. Accurate information on the nutritive value of feeds is essential for accurate ration formulation. A series of experiments was carried out to determine various nutritional characteristics of concentrate ingredients either locally produced or imported into Ireland. From these experiments it was concluded that : * The digestibility values of concentrate ingredients derived in maintenance-fed sheep are applicable to maintenance-fed cattle. * Feed is not utilised as efficiently when the level of feeding is increased from maintenance to 2 x maintenance. * The improved feed conversion efficiency in steers offered a restricted allowance of concentrates cannot be attributed to a difference in digestibility but can be attributed in part to a lower rate of fat deposition compared to steers offered ad libitum concentrates. * The residue after oil extraction from Camelina sativa could replace some imported protein-rich feedstuffs in ruminant rations but to fully achieve this potential, the residual oil content must be decreased. * For measurement of ruminal degradability of concentrate ingredients a wide range of forage to concentrate ratios and feeding levels can be used. * It is important to consider the actual outflow rate of nutrients from the rumen when measuring the feed value of individual concentrate ingredients as this can have an impact on the effective degradability and the relative nutritive values assigned to such ingredients. * Large variations in ruminal degradation occur within and among feeds. The ruminal degradability of different samples of any one feed should be measured to determine their true nutritive value for feeding ruminants. * Within most concentrate ingredients examined, the variation in small intestinal digestibility (SID) due to source indicates a range in the quantity of amino acids supplied to the animal for productive purposes. The more rapid and cost effective in vitro technique can be used to screen the SID of concentrate ingredients. * Target volatile fatty acid (VFA) concentrations and proportions may be produced by varying the proportions of the individual ingredients in a concentrate ration. * An in vitro procedure allowed VFA production to be measured across a large range of feeds under standardised conditions. * On average, 75% of gas produced during ruminal fermentation consists of carbon dioxide. The variation in methane production among individual concentrate ingredients provides an opportunity to formulate rations to minimize environmental pollution with methane.
    • Chemical and biological control of mushroom pests and diseases.

      Staunton, Liam; Dunne, R.; Cormican, T.; Donovan, M. (Teagasc, 1999-03-01)
      This study set out to determine the occurrence of diseases and pests in Irish mushroom units and their method of control using chemical, biological and other means of control. It also examined the role of a combination of these methods to enable control with minimal pesticide input. It was found that pesticides alone will never give effective disease and pest control and that they should only be considered an adjunct to the implementation of other methods. They include: (1) Exclusion (2) Containment of spread (3) Elimination. A major factor in good disease and pest control was found to be the implementation of a good programme of hygiene which must be followed from the time of filling a tunnel to the time of emptying after cropping. Biological systems offer good potential for control but at present are not as effective as the best chemical control methods.
    • Chemical Composition and Processability of Milks from Herds with Different Calving Patterns.

      O'Brien, Bernadette (Teagasc, 1999-04-01)
      The primary objective of this project was to research the detailed composition and processability of milk produced by spring calving, autumn calving and combined herds. This information is required as it may influence the future value of milk and allow informed decisions to be made by the dairy industry regarding diversification of the present product range. Specific issues to be established included (i) the processing characteristics of late lactation milk from well managed spring and autumn-calved herds and the lactation stage cutoff point for product manufacture from such milks, based on quality and functionality, (ii) the processing characteristics of mid and early lactation milk from well managed spring and autumn-calved herds, respectively, (iii) the volume of early lactation milk required to mix with late lactation milk in order to maintain milk processing quality and (iv) the difference (if any) in processing characteristics of bulk spring/autumn milks mixed at the farm or the processing plant. By maintaining spring-calved cows on a good plane of nutrition in late lactation, milk yield, composition and processing characteristics and quality of Mozzarella cheese can be sustained until late November/early December (~275 DIM [days in milk]). In general there were no notable adverse effects of stage of lactation on the composition or processing characteristics of late lactation autumn milk or on the quality and functionality of Mozzarella cheese made from it, during the lactation period 240-330 DIM (up to mid/late August). Early lactation autumn and mid lactation spring milks generally had better processing characteristics than late lactation spring and autumn milks, respectively. Combining early lactation milk with late lactation milk improved the processing characteristics of the late lactation milk and overcame any processing problems associated with it. Approximately 70 % of autumn milk is required in a spring/autumn bulk milk to maintain processability and to improve the milk sufficiently for cheesemaking from 275 DIM of the spring lactation. Mixing of late lactation spring milk with early lactation autumn milk at the factory from separate herds would result in similar processing characteristics to milk from a mixed spring and autumn calving herd. In conclusion, the manufacturing period for spring milk in late autumn/winter may be extended by good herd management practices on-farm. In addition, the production of autumn milk in combination with this allows a further extension of the manufacturing period. Alternatively, autumn milk may be used exclusively for short shelf-life products. This information suggests that it is possible to overcome the traditional milk processing problems experienced due to the seasonal pattern of milk production in Ireland.
    • Coffee-Stability of Agglomerated Whole Milk Powder and other Dairy Creamer Emulsions

      Kelly, Philip; Oldfield, D.J.; Teehan, C.M. (Teagasc, 1999-02-01)
      The objectives of this project were: (a) to investigate the circumstances that cause milk powders and creamers to fail when added to coffee based beverages; (b) to evaluate the role of processing variables in relation to their thermostabilising effects on milk during drying of coffee whiteners; and (c) to determine the role of emulsion formation on the stability of imitation creamers.
    • Collection and rejuvenation of rare/scarce plants for the nursey stock industry.

      Murphy, Richard F.; Douglas, Gerry C. (Teagasc, 1999-12-01)
      The main objectives of this project were: • Location of scarce/rare or new plants of high garden merit with tolerance to disease and pests • Rejuvenation. • Conservation of rejuvenated plants in the original gardens from which they were collected, at the Kinsealy Research Centre and in other selected locations. • Evaluation of the collection for a variety of uses – foliage, patio etc. over a range of different conditions and locations. • Plant identification. • Commercialisation of these plants by the trade to extend their range of plants.
    • Commercial systems for ultra-rapid chilling of lamb

      Redmond, Grainne; McGeehin, Brian; Henchion, Maeve; Sheridan, James J.; Troy, Declan J.; Cowan, Cathal; Butler, Francis (Teagasc, 2001-08)
      The overall objective was to devise a rapid chilling system for the Irish lamb processing industry. The objective of the first trial was to assess the effect of ultra-rapid chilling in air at - 4ºC, -10ºC and -20ºC and subsequent ageing on the appearance and tenderness of lamb carcasses. The objective of the next trial was to investigate the effect of carcass splitting, which produces faster chilling rates and reduces skeletal constraint of muscles, on the tenderness of rapidly and conventionally chilled lamb. The next task was to compare the effects of immersion chilling and conventional air chilling on meat tenderness and evaporative weight loss in lamb carcasses. The next task was to assess the level of interest in industry. This required costings of the process and a survey of several lamb processors focusing on their perceptions of rapid chilling in general, its advantages and disadvantages, and the implications of adopting the new system. The final objective was to introduce the ultra-rapid chilling process to industry via a factory trial. Lambs were ultra-rapidly chilled and then exported to France for assessment.
    • Comparison of breed of dairy cow under grass-based spring milk production systems

      Buckley, Frank; Walsh, S.W.; Dillon, Pat; National Development Plan (NDP) (Teagasc, 2006-01-01)
      The objective of this study was to investigate the potential differences among different dairy cow breeds across two feeding systems on milk production, udder health, milking characteristics, body weight, body condition score, hormone parameters, ovarian function, survival and overall reproductive efficiency. The breeds investigated included Holstein-Friesian (HF), Montbéliarde (MB), Normande (NM), Norwegian Red (NRF) and Holstein- Friesian × Montbéliarde (MBX) and Holstein- Friesian × Normande (NMX). Selection within the HF breed has, until recently, been predominantly for milk production with little or no direct selection for functional traits other than those correlated with superior type. The MB and the NM have been simultaneously selected for both milk and beef production in the past. The NRF were imported as calves and come from a more balanced total merit index incorporating production and cow functionality since the early 1970s. The dairy cow breeds were grouped into blocks of two within breed groups and randomized across two spring-calving grass-based feeding systems: low concentrate feeding system (LC) and high concentrate feeding system (HC). Those on LC feeding system were offered approximately 530 kg/cow over the total lactation, while those on HC feeding system were offered approximately 1030 kg/cow.
    • Comparison of breed of dairy cow under grass-based spring milk production systems.

      Buckley, Frank; Walsh, S.W.; Dillon, Pat (Teagasc, 2006-01)
      The objective of this study was to investigate the potential differences among different dairy cow breeds across two feeding systems on milk production, udder health, milking characteristics, body weight, body condition score, hormone parameters, ovarian function, survival and overall reproductive efficiency. The breeds investigated included Holstein-Friesian (HF), Montbéliarde (MB), Normande (NM), Norwegian Red (NRF) and Holstein- Friesian × Montbéliarde (MBX) and Holstein- Friesian × Normande (NMX). Selection within the HF breed has, until recently, been predominantly for milk production with little or no direct selection for functional traits other than those correlated with superior type. The MB and the NM have been simultaneously selected for both milk and beef production in the past. The NRF were imported as calves and come from a more balanced total merit index incorporating production and cow functionality since the early 1970s. The dairy cow breeds were grouped into blocks of two within breed groups and randomized across two spring-calving grass-based feeding systems: low concentrate feeding system (LC) and high concentrate feeding system (HC). Those on LC feeding system were offered approximately 530 kg/cow over the total lactation, while those on HC feeding system were offered approximately 1030 kg/cow. There was no genotype by environment interaction observed for any of the milk production, BCS, BW, udder health, milking characteristics, reproductive performance or feed intake/efficiency parameters investigated. Compared to the MB and NM, all other breeds had higher total lactation milk, fat, protein and lactose yield, with the HF having the highest. Animals on the HC feeding system had higher total lactation milk, fat, protein and lactose yield. Compared to the NRF, SCS was higher for the HF, NM, MBX and NMX breed groups, while SCS of the MB was not different. The NM and MB had lower AMF compared to all breeds. The crossbreds achieved the higher AMF. The NM had the lowest PMF, while that of the crossbreds were higher compared to all breeds. Milking duration was not affected by breed. Differences between breeds for AMF, PMF and MD were not apparent after adjustment for milk yield. Animals offered a HC diet had higher AMF, PMF and MD compared to those on the LC feeding system. Somatic cell score did not differ between the feeding systems. The interaction between breed and milk yield influenced SCS, AMF, PMF and MD thus implying that for each unit increase of milk yield by breed, the response in SCS, AMF, PMF and MD was different for some breeds. The response in SCS was similar for the NRF, MBX and NMX, while MD was similar for the MB and MBX. The effect of one unit increase in daily average milk yield caused a favourable decrease in SCS; however a one unit increase in PMF and MD did not influence SCS. No interactions were observed for breed with any milking characteristic on SCS. The HF had the lowest BCS, the MB and NM the highest, while the NRF, MBX and NMX were intermediate. The NRF had the lowest BW; the NM had the highest while the other breeds were intermediate. The NRF had increased likelihood of SR24, PREG1, PREG42 and FINALPR and greater survival compared to the HF. Both MBX and NMX had shorter CSI and CCI and were more likely to be pregnant at the end of the breeding season, thus had higher survival rates compared to the HF; however heterosis estimates for these traits was not significant, likely due to the small data size. Feed system did not influence reproductive performance of the different breeds. Breed of dairy cow did not influence any of the ovarian parameters studied. Breed of dairy cow did not influence insulin or IGF-1 concentrations at any sampling period. Breed significantly effected gestation length, calf birth weight and calving ease score. The NRF had the shortest gestation, lightest calves and least calving difficulty. Genotype had a significant effect on estimated dry matter intake, being highest with the HF, MBX, NMX and lowest with NM and NRF. Genotype also had a significant effect on yield of milk solids per kg of DMI. The highest yield of milk solids per kg of DMI was achieved with the NRF, HF and MBX. Comparisons between genotypes reveal that estimated residual feed intake estimates were lowest (most favourable) for the NRF, compared to other genotypes with the exception of HF.
    • Comparison of Cereals Grown Under High (Conventional) and Low (Reduced) Inputs Systems

      Conroy, M.J.; Hogan, J.J. (Teagasc, 2001-06-01)
      This long-term experiment, which commenced at Oak Park in September 1994, compared the effect of a high inputs system with a low inputs system on the yield and quality of winter wheat and winter barley grown (i) In a non-cereal break-crop rotation with spring barley (ii) In a continuous cereal break-crop rotation with winter oats, and (iii) Continuous cereals. The experimental site at Knockbeg consisted of a medium-heavy textured, freedraining grey-brown podzolic soil (Knockbeg Series). The objective of the experiment was to measure the effect of reduced inputs on grain yield, grain quality, production costs and the profitability of the important cereal crops grown in different rotations, so that the impact of a more environmentally-friendly inputs system could be assessed and compared with conventional production systems.
    • A comparison of Charolais and beef X Friesian suckler cows.

      Drennan, Michael J; Fallon, Richard J. (Teagasc, 1998-10-01)
      The studies carried out included comparisons of Charolais and Beef x Friesian suckler cows in terms of voluntary silage intake, colostrum yield and immunoglobulin level, calf immunoglobulin level and cow milk yield in addition to animal production experiments. In all experiments the Charolais animals used were a minimum of 7/8 Charolais and were the result of an upgrading programme at Grange commencing with Charolais x Friesians. In the production experiments, only Hereford x Friesian cows (and their progeny) were compared with the Charolais while in all other experiments the Beef x Friesians included both Hereford x Friesians and Limousin x Friesians.
    • A Comparison of the Productivity of Suckler Cows of Different Breed Composition

      Drennan, Michael J; Murphy, B.M. (Teagasc, 2006-01)
      Growth rate and carcass value are important determinants of profitability, with carcasses of good conformation (muscularity) commanding the highest prices on the premium export markets (mainland EU). Therefore, the objective in suckling is that the progeny are of high growth potential and produce carcasses of good conformation. Breed is the major factor influencing conformation, with the late-maturing continental breeds superior to the early-maturing British breeds (Hereford and Aberdeen Angus) and vastly superior to the Friesian/Holstein. The continental breeds also have greater growth potential than the other breeds. The type of carcasses required are similar to those produced from the suckler herd in France where over 80% of cows are purebred Charolais, Limousin or Blonde d'Aquitaine. However, experimental data have shown that the heterosis (hybrid vigour) resulting from use of a crossbred as opposed to purebred cows increases the weight of calf weaned per cow bred by 14%, with a further 8% arising from using a third breed of sire on a crossbred cow. Because of the emphasis on conformation, producers are retaining replacements from within the herds with a tendency towards purebreds rather than crossbreds. It is thus important to examine the relative productivity of various crossbred and purebred cows to provide clear guidelines on the most desirable breeding programme for the suckler herd. The project involved 5 cow breed types (0.5, 0.75 and 1.0 Limousin genes, Simmental x (Limousin x Friesian) and purebred Charolais) with a common sire used on all cows. Progeny were taken to slaughter. The usefulness of ultrasonic scanning and visual muscular scoring in predicting carcass conformation, fat and composition was also examined.
    • A Comparison of the Productivity of Suckler Cows of Different Breed Composition

      Drennan, Michael J; Murphy, B.M. (Teagasc, 2006-01-01)
      The findings obtained in a comparison of 5 suckler dam breed types {Limousin x Friesian (LF), Limousin x (Limousin x Friesian) (LLF), Limousin (L), Charolais (C) and Simmental x (Limousin x Friesian) (SLF)} and their progeny through to slaughter
    • Competitiveness In Irish Sheep Production

      Connolly, Liam (Teagasc, 1999-03-01)
      The main objective of this study was to examine and compare lowland sheep production in France, the UK, New Zealand and Ireland. Ireland, the UK and New Zealand were selected as being the main exporting countries, whilst France is the main EU importing country and is also a major sheep producer. Sheep is not a major contributor to agricultural output in the 3 EU countries but contributes 17.5% to output in New Zealand. New Zealand had the largest breeding flock size at 1,890 ewes compared to 223 ewes in the UK and 112 and 104 ewes in France and Ireland respectively. French and UK lamb carcass weights were similar at 17.5kg compared to 18.5kg in Ireland and 15.9kg in New Zealand. French farmers obtained the highest prices for their lamb, whilst UK and Irish prices were broadly similar and approximately three times greater than New Zealand lamb prices. Total receipts to Irish farmers i.e. lamb sales and subsidies were approximately 4.5 times greater than receipts to New Zealand producers. Lamb carcass classification schemes were in operation for many years in all countries except Ireland where a scheme was introduced in recent years. UK producers had the best technical performance producing 18.3 lambs per hectare compared to 11.7 in Ireland, 9.8 in France and 12.7 in New Zealand. Financial output per ewe was highest in France but direct and overhead costs were also much higher resulting in France having a lower net margin than either the UK or Ireland but higher than New Zealand due mainly to low product prices. The total cost of producing 1kg of lamb carcass was highest in France at IR£3.44, compared to IR£2.06 in the UK, IR£1.92 in Ireland and IR£1.20 in New Zealand. New Zealand sheep producers have a comparative advantage over EU producers and can produce lamb at less than half the cost in addition to having a much higher throughput per labour unit. The most notable features of New Zealand sheep production in relation to EU production are the larger scale of operation; low direct costs of production; low labour input; the high level of specialisation and the level of technical efficiency achieved.
    • The competitiveness of the Irish food processing industry

      Pitts, Eamonn; O'Connell, Larry; McCarthy, B. (Teagasc, 2001-07)
      Ways of measuring industrial competitiveness are discussed and an analysis of the competitiveness of the food sector as a whole and of three sub-sectors are presented. The techniques employed were Revealed Comparative Advantage and the Porter Diamond.
    • Concentrate Supplementation of Pasture for Beef Production

      French, Padraig; O'Riordan, Edward G.; O'Kiely, Padraig; Moloney, Aidan P (Teagasc, 2001-03-01)
      * Unsupplemented cattle offered a high grass allowance (18 kg (DM)/head/day), achieved 0.97 of the DM intake of a positive control offered concentrates ad-libitium. At a low grass allowance (6 kg/DM/head/day), there was no effect of supplementary concentrates on grass intake. At a medium (12 kg/DM/head/day), and high grass allowance, supplementary concentrates reduced grass intake by 0.43 and 0.81 kg/DM respectively per kg/DM concentrate offered. * Supplementary concentrates increased complete diet digestibility even though offering supplementary concentrates also increased total DM intake. Complete diet digestibility was higher than the additive values of the grass and concentrates. This would imply that the supplementary concentrates increased the grass DM digestibility. * Increasing the grass allowance increased plasma urea concentration; supplementary concentrates increased total dietary nitrogen intake and reduced plasma urea concentration. These findings suggest that the concentrate supplement enabled greater utilisation by rumen micro-organisms of the degradable nitrogen supplied by the grass. * Supplementing with concentrates increased carcass growth by 116 g/kg concentrate DM eaten whereas increasing the grass allowance increased carcass growth by 38 g/kg/DM grass eaten. The carcass weight response to concentrates of grazing animals was twice that of animals offered concentrates ad-libitum which gained 57 g carcass per kg concentrate DM eaten. * The relationship between carcass gain (Y) (kg/day) and supplementary concentrates (X) (kg/day) was quadratic (P< 0.001) and was best described by the equation: Y = -0.0099X2 + 0.1364X + 0.2459 (R2 = 0.60). The relationship between carcass gain (Y) (kg day-1) and grass intake (X) was also quadratic (P< 0.01) and was best described by the equation: Y = -43X2 + 275X + 133 (R2 = 0.48). Although there was a much larger (double) carcass growth response to supplementary concentrates than to additional grass DM eaten, increasing grass intake significantly increased carcass fat scores whereas offering supplementary concentrates did not. This would imply that relative to concentrates, autumn grass led to a change in the partitioning of energy from muscle towards subcutaneous fat. * As a strategy for increasing the performance of cattle grazing the type of autumn grass used in this study, offering supplementary concentrates offers more scope to improve animal performance than altering grass allowance. * The carbohydrate source of the three concentrates formulated to differ in rate of degradability did not alter rumen fluid pH, volatile fatty acid (VFA) concentration or the rate of grass DM or N degradation when grass supply was considered to be limiting or liberal. The autumn grass was apparently capable of buffering the effects of concentrate DM degradation rate which varied by up to two fold. * The rumen fluid parameters were more influenced by the pat-tern of grass intake than type of concentrate offered. Hence, there was no effect of concentrate type on animal performance.
    • Concentrate Supplements for Weanling and Finishing Steers

      Keane, Michael G. (Teagasc, 2003-03-01)
      Concentrates are a major cost element in feeding beef cattle in winter. Because of the need to retain finishing cattle until after specific dates to comply with retention periods for the draw-down of premia, feeding strategies must be flexible. The objectives of this study were to examine concentrate feeding strategies which would minimise concentrate feeding to weanlings and exploit compensatory growth, simplify feeding routines and improve the efficiency of concentrate utilisation in finishing cattle. Four experiments were carried out, two with weanlings and two with finishing cattle. • Weanlings fed outdoors (in sacrifice paddocks) in winter gained 13 kg more than those similarly fed indoors but by the end of the following grazing season the weight difference had decreased to 4 kg as a result of compensatory growth. • There was no response to an increase in protein level in the concentrate. • Feeding 2 kg/day of supplementary concentrates with silage in winter reduced silage intake by 0.4 kg dry matter (DM) and increased total DM intake by 1.27 kg/day. • The liveweight gain response in winter to 2 kg/day supplementary concentrates was 344 g/day or a total of 44 kg. By the end of the following grazing season this had declined to 14 kg (68% compensation) • The conversion ratio of concentrate DM to liveweight was about 5:1 at the end of winter but by the end of the following grazing season it was over 15 : 1. • Feeding a fixed total concentrate allowance to weanlings gave a better response when it was offered at a flat rate daily over the whole winter, or at a high rate over the first half of the winter, rather than when offered at a high rate over the second half of the winter. • Feeding a fixed total concentrate allowance ad libitum over the final part of the finishing period was superior to feeding it at a flat rate per day over the total period in terms of feed energy utilization. • There was no impairment in the efficiency of total feed energy utilization by delaying the feeding of a fixed concentrate allowance for up to 70 days after housing compared to feeding it immediately after housing. • Where animals are being finished over a 5-6 months period, rather than feeding concentrates at a flat rate throughout the whole period, it is better to delay introduction for 2-3 months and then offer concentrates ad libitum thereafter. • As the interval from housing to concentrate introduction increases, the response to concentrates fed ad libitum subsequently increases. • Although not reflected in carcass fat score, objective indicators of fatness were lower for animals fed concentrates ad libitum than for animals fed concentrates at a flat rate with silage.
    • Confirmation of co-denitrification in grazed grassland

      Selbie, Diana R.; Lanigan, Gary; Laughlin, Ronald J.; Di, H.J.; Moir, James L.; Cameron, K.C.; Clough, Timothy J.; Watson, C. J.; Grant, Jim; Somers, Cathal; et al. (Nature Publishing Group, 30/11/2015)
      Pasture-based livestock systems are often associated with losses of reactive forms of nitrogen (N) to the environment. Research has focused on losses to air and water due to the health, economic and environmental impacts of reactive N. Di-nitrogen (N2) emissions are still poorly characterized, both in terms of the processes involved and their magnitude, due to financial and methodological constraints. Relatively few studies have focused on quantifying N2 losses in vivo and fewer still have examined the relative contribution of the different N2 emission processes, particularly in grazed pastures. We used a combination of a high 15N isotopic enrichment of applied N with a high precision of determination of 15N isotopic enrichment by isotope-ratio mass spectrometry to measure N2 emissions in the field. We report that 55.8 g N m−2 (95%, CI 38 to 77 g m−2) was emitted as N2 by the process of co-denitrification in pastoral soils over 123 days following urine deposition (100 g N m−2), compared to only 1.1 g N m−2 (0.4 to 2.8 g m−2) from denitrification. This study provides strong evidence for co-denitrification as a major N2 production pathway, which has significant implications for understanding the N budgets of pastoral ecosystems.