Irish Journal of Agricultural and Food Research Volume 42, Issue 1

Potential impacts of climate change on maize production and the introduction of soybean in Ireland

N.M. Holden† and A.J. Brereton

Department of Agricultural and Food Engineering, University College Dublin, Earlsfort Terrace, Dublin 2

The impact of climate change on agriculture can be assessed by evaluating changes in yield using simulation models. Maize was investigated because it was until recently a semi-marginal crop that is now regarded as a good source of high energy forage in Ireland. Soybean was investigated because it is not currently suitable for commercial production in Ireland but is used as a protein supplement by livestock producers. With climate change soybean may become a viable forage crop. The aim of this work was to evaluate the impact of climate change on maize and soybean yield in Ireland using crop simulation models and climate scenario data to assess potential changes between baseline and future scenarios, and to assess some of the implications of these changes. The models used for this work are part of the Decision Support System for Agrotechnology Transfer (DSSAT). Simulation results for the baseline climate were compared with available data and indicated that the models were acceptable for use in Irish conditions. The soil descriptions were based on a simplification of the General Soil Map of Ireland into seven classes. Simulations were undertaken for a 10 km × 10 km grid over Ireland for grid cells representing <150 m altitude and with mineral soil (not allocated as peat or urban/water), for 30 replicate years in each cell, for each of three scenarios (baseline, 2055, 2075). It was concluded that maize could become a major crop in Ireland but may suffer water stress in summer, and that soybean may become a specialist, marginal crop.>

Keywords: Climate change; crop models; maize; soybean

Linear models for the dry matter yield of the primary growth of a permanent grassland pasture

D. Han^1,2, P. O'Kiely¹† and D.-W. Sun²

¹ Teagasc, Grange Research Centre, Dunsany, Co. Meath
² Department of Agricultural and Food Engineering, University College Dublin, Earlsfort Terrace, Dublin 2

Herbage dry matter yield (DMY) growth pattern of the primary growth of a permanent grassland pasture (PGP) managed for silage production was investigated through a field experiment, and linear statistical models utilising meteorological and growth duration variables were formulated and tested. During 5 consecutive years the herbage DMY was measured weekly between late April and early July. Correlation and multiple linear regression analyses were carried out to examine the relationships between DMY and the most relevant meteorological variables envisaged (rain, evaporation, daily mean, maximum and minimum air temperature, global solar radiation and their interactions) and grass growth duration. The results show that under the conditions prevailing in the experiment, DMY was highly correlated with accumulated daily mean air temperature, accumulated global solar radiation, accumulated evaporation and grass growth duration, particularly for the period before early June. Models are recommended for different periods of herbage growth. The models recommended for the whole primary growth period and for the growth period before 1 June had coefficients of determination above 0.94. Residual analyses and comparisons between model prediction and independent field data confirmed that the recommended models are robust.

Keywords: Grass; model; prediction; silage; yield

Linear models for the in vitro dry matter digestibility of the primary growth of a permanent grassland pasture

D. Han^1,2, D.-W. Sun¹ and P. O'Kiely²†

¹ Department of Agricultural and Food Engineering, University College Dublin, Earlsfort Terrace, Dublin 2
² Teagasc, Grange Research Centre, Dunsany, Co. Meath

Herbage dry matter digestibility change patterns of the primary growth of a permanent grassland pasture managed for silage production were investigated through a field plot experiment. Herbage in vitro dry matter digestibility (IVDMD) was measured at weekly intervals from late April to early July in 5 consecutive years. Correlations between IVDMD and six groups of growth-controlling variables were assessed. Each group of variables included herbage growth days, dry matter yield, accumulation of daily mean air temperature, daily maximum air temperature, daily minimum air temperature, global solar radiation, precipitation and evaporation. Variables that were more closely correlated with herbage IVDMD were identified and used as regression variables in subsequent multiple linear regression analyses. It was found that herbage IVDMD was closely correlated with the accumulation of daily mean air temperature, global solar radiation, evaporation, grass growth days and herbage dry matter yield. Its change pattern could largely be explained by the meteorological conditions and growth days that the sward had experienced. Two linear models were recommended for herbage IVDMD estimation under conditions similar to those prevailing in this experiment. The models had coefficients of determination (R²) over 0.83 and their effectiveness was tested and confirmed with an independent data set of IVDMD and meteorological variables.

Keywords: Digestibility; grass; model; silage

The effect of concentrate type on herbage intake, diet composition and grazing behaviour of dairy cows and the association with sward characteristics

G. Stakelum† and P. Dillon

Teagasc, Moorepark Research Centre, Fermoy, Co. Cork

Four groups of three cows each plus four oesophageal fistulated cows were used in a 4 × 4 greco-latin square experiment to examine the effects of concentrate type on herbage organic matter intake (OMI), dietary composition and grazing behaviour. The treatments were grazed herbage and 0.5 kg /day of a calcined-magnesite pellet (H), or H plus a concentrate supplement (3 kg /day) of barley (B), beet pulp (BP) or molassed beet pulp (MBP). The squares (SQ) were repeated twice. A two-stage sward cutting technique was used to measure OMI with 24-h grazing plots. The herbage was primary spring growth for the first SQ and regrowth of 21 to 28 days for the second SQ. The periods were 7 days in duration. The experiment was conducted from 10 April to 5 June. Daily herbage allowance was 22.0 kg (s.e. = 0.12) per cow. Mean sward height (SH), herbage mass above 3 cm (HM), herbage organic matter digestibility (OMD) and herbage crude protein (CP) values were 21.8 cm (s.e. = 0.35), 3059 kg OM /ha (s.e. = 78.7), 831 g /kg (s.e. = 1.2) and 195 g /kg OM (s.e. = 1.8), respectively, and were similar for all treatments. The substitution rate of concentrate OMI for herbage OMI was 0.32, 0.63 and 1.39 kg /kg, for MBP, BP and B, respectively. HM after grazing was 1117, 1311, 1348 and 1497 kg OM/ha (s.e. = 60.2), for H, MBP, BP and B, respectively. There were reductions in daily grazing time of 8, 13 and 23 min/kg of concentrate OMI for MBP, BP and B, respectively. The mean diet herbage OMD and CP were 853 g/kg (s.e. = 1.4) and 251 g/kg (s.e. = 7.0), respectively, with no effect of treatment. Herbage OMI was related to herbage OMD as follows: ñ2015 + 4.78 × OMD ñ 0.002817 × OMD² (R² = 0.98, r.s.d. = 0.139). The results indicate that fibrous concentrates have a less depressing effect on grass intake than cereal (starchy) based concentrates.

Keywords: Concentrate; dairy cows; fibre; intake; sward

A comparison of Simmental × Holstein-Friesian and Piemontese × Holstein-Friesian cows in a hill suckler herd: 1. Reproduction and calf performance to weaning

R. Keatinge¹, D.G. Chapple²†, R. Hardy³ and D.W. Wilson⁴

¹ ADAS Redesdale, Rochester, Otterburn, Newcastle upon Tyne NE19 1SB, UK
² ADAS Rosemaund, Preston Wynne, Hereford HR1 3PG, UK
³ ADAS Wolverhampton, Woodthorne, Wergs Road, Wolverhampton WV6 8TQ, UK
⁴ ADAS Gleadthorpe, Meden Vale, Mansfield, Nottinghamshire NG20 9PF, UK

Simmental × Holstein-Friesian (S) and Piemontese × Holstein-Friesian (P) suckler cows representing, respectively, a large cow type with good milking ability and a medium-sized cow type with a reputation for good meat quality, were compared in an autumn-calving production system. Reproductive performance and calf rearing ability were assessed over four successive seasons from breeding as heifers to fourth parity. During that period they were mated to a range of late maturing terminal sires. From a total of 130 and 132 matings, the calving percentages were 91 and 86 for S and P, respectively. From 69 and 74 heifer matings, the corresponding percentages were 90 and 88, respectively. Overall gestation length (291 days) and calving interval (367 days) were similar for the two dam types. Piemontese cross cows produced consistently lighter weaned calves at approximately 8 months of age. Over the 4-year period, mean bull calf growth rates to weaning were 1.28 and 1.17 (s.e.d. 0.022, P < 0.001) kg/day for S and P, respectively. The corresponding values for heifer calves were 1.12 and 1.04 kg/day (s.e.d. 0.022, P < 0.001). These results demonstrate that high performance can be obtained on suckled calves under favourable hill and upland conditions. However, to offset the lower calf growth rate and poorer reproductive performance of the P dams a price premium per kg of weaned calf is required. Such a premium could only be justified on the basis of improved finishing performance and/or greater unit carcass value.

Keywords: Beef cattle; Piemontese; Simmental; suckler cows

A comparison of Simmental × Holstein-Friesian and Piemontese × Holstein-Friesian cows in a hill suckler herd: 2. Performance of the progeny during finishing

D.G. Chapple¹†, H.F. Grundy¹, R. Hardy², R. Keatinge³ and D.W. Wilson⁴

¹ ADAS Rosemaund, Preston Wynne, Hereford HR1 3PG, UK
² ADAS Wolverhampton, Woodthorne, Wergs Road, Wolverhampton WV6 8TQ, UK
³ ADAS Redesdale, Rochester, Otterburn, Newcastle upon Tyne NE19 1SB, UK
⁴ ADAS Gleadthorpe, Meden Vale, Mansfield, Nottinghamshire NG20 9PF, UK

The performance during finishing of the progeny of autumn-calving Simmental (S) and Piemontese (P) × Holstein-Friesian suckler cows sired by either Limousin (L) or Charolais (C) bulls was evaluated over 3 years. The calves from a hill suckler herd commenced finishing immediately after weaning at approximately 8 months of age. Mean weaning weights were 344 and 314 kg (bulls) and 313 and 290 kg (heifers) for S and P, respectively. Dressing proportion of heifers out of P cows was significantly higher (P < 0.001) than for those out of S cows in all years and was also significantly higher (P < 0.001) for bulls out of P cows in year 1. Bulls and heifers out of S dams tended to be fatter than bulls and heifers from P dams and this was significant (P < 0.05) in year 1. Male progeny from Charolais sires were significantly heavier at slaughter and had higher carcass weights (P < 0.05) than male progeny from Limousin sires. Likewise female progeny sired by Charolais were also significantly heavier at slaughter (P < 0.01). However, the L heifers had a higher dressing proportion (P < 0.01) with the result that carcass weights were similar for the two sire breeds. Carcass fatness grades were similar for L and S sires but heifer conformation grade was superior (P < 0.05) for L sires.

Keywords: Beef cattle; grass silage; Piemontese; Simmental; supplementation.

The effect of floor type and space allowance on welfare indicators of finishing steers

M.C. Hickey¹†, B. Earley¹ and A.D. Fisher²

¹ Teagasc, Grange Research Centre, Dunsany, Co. Meath
² AgResearch, Ruakura, Hamilton, New Zealand

Stocking density and floor surface type are two factors which could influence animal welfare on slatted accommodation. The objectives of this experiment were to determine the effects of space allowance on slatted floors (1.5, 2.0, 3.0 or 4.0 m² /head) and floor type (slats v. straw) on the welfare of finishing steers. Seventy-five Friesian steers (mean live weight 516 kg) were blocked on bodyweight and randomly assigned from within blocks (n = 15) to one of five housing treatments, with three groups of five steers per treatment. Over a 3-month period, animals were offered concentrates ad libitum plus 2 kg silage dry matter (DM) per head daily. Animal behaviour (lying, eating and social interactions) was measured. Blood cell profiles and plasma metabolite, immune status and acute phase protein concentrations were also measured. Time spent lying was reduced at <2 m>² /head (P < 0.05), while animals lay longer on straw beds when compared with animals housed on slats at 3 m² /head (P < 0.05). There was no effect of space allowance on group social, aggressive, grooming or stereotypic behaviours. The frequency of social interactions was reduced (P < 0.001) at 1.5 m² when compared with animals housed on straw at 4 m² /head. There was no effect of space allowance or floor type on blood cell counts, blood metabolites, haptoglobin or fibrinogen levels. Increasing space allowance above 2 m² /head, but not floor type, increased carcass gain (P < 0.001) and decreased feed conversion ratio (kg DM intake /kg carcass gain, P < 0.05). In vitro interferon-γ response was compromised when animals were housed at ≤ 2 m² /head (P < 0.05) but was not affected by floor type. It is concluded that space allowance less than 3 m² /animal adversely affected animal welfare.

Keywords: Cattle; floor type; housing; space allowance; welfare

Effect of two microbial phytases on the performance and nutrient retention on grower-finisher pigs fed barley-maize-soyabean meal-based diets

S.M. Brady¹, J.J. Callan¹, D. Cowan², M. McGrane³ and J.V. Oí Doherty¹†

¹ University College Dublin, Lyons Research Farm, Newcastle, Co. Dublin
² Novo Nordisk S.A., 282 Chartridge Lane, Chesham, Bucks, UK
³ Trouw Nutrition, 206 Ryevale Lawns, Leixlip, Co. Kildare, Ireland

Two experiments were conducted to investigate the effects of the inclusion of Aspergillus oryzae (A. oryzae) and Peniophora lycii (P. lycii) phytase enzymes on nutrient retention, growth performance, carcass characteristics and bone parameters when offered to grower-finisher pigs (36 to 95 kg live weight). The experiment was a completely randomised design and the pigs were offered, individually, barley-maize- soyabean meal-based diets containing: adequate P and Ca (T1) (2.3 g available P/kg and 7.4 g Ca/kg), low P (T2) (1.3 g available P/kg and 5.3 g Ca/kg), low P + 500 units A. oryzae phytase/kg (T3), low P + 500 units P. lycii phytase/kg (T4), low P + 750 units P. lycii phytase/kg (T5) and low P + 1000 units P. lycii phytase/kg (T6). The pigs offered the low-P diet had a lower faecal-P excretion (P < 0.01) and P digestibility (P < 0.001) than the pigs offered the adequate-P diet. The inclusion of A. oryzae phytase in the low-P diet resulted in increases in the digestibility of ash (P < 0.05), P (P < 0.001) and Ca (P < 0.05). Supplementation of the low-P diet with P. lycii phytase resulted in a linear increase in the digestibility of N (P < 0.01), gross energy (P < 0.001), P (P < 0.001), Ca (P < 0.05) and Zn (P < 0.05). Feeding the unsupplemented low-P diet resulted in a decrease in daily gain (P < 0.01), feed intake (P < 0.05) and food conversion ratio (FCR) (P < 0.05) during the finisher period (60 to 95 kg) compared to the adequate-P diet. Supplementing the low-P diet with A. oryzae phytase increased daily gain (P < 0.001) and intake (P < 0.001) compared to the low-P diet. There was a quadratic response in feed intake (P < 0.01) and daily gain (P < 0.05) to increases in the P. lycii phytase concentration in the diet with no benefit from phytase inclusion above 500 units/kg. There was a linear improvement in carcass FCR (P < 0.05) and a linear increase in bone ash (P < 0.05), bone P (P < 0.01) and bone Ca (P < 0.01) and a linear decrease in lean yield (P < 0.05) in response to increased concentration of P. lycii phytase in the diet.

Keywords: Carcass; phosphorus; phytase strain; pigs

Development of pH sensitive films for monitoring spoilage volatiles released into packaged fish headspace

L. Byrne, K.T. Lau and D. Diamond†

National Centre for Sensor Research (NCSR), School of Chemical Sciences, Dublin City University, Dublin 9

Amines such as trimethylamine (TMA), dimethylamine (DMA) and NH₃, collectively known as total volatile basic nitrogen (TVB-N), are released from fish during spoilage. Cresol red was successfully entrapped within a plasticised cellulose acetate matrix to produce sensors that could monitor the levels of TVB-N released from fish. The dye does not differentiate between the different bases that are released during spoilage but instead responds to any base capable of deprotonating it. Calibration of the sensors using a red light source and a monochrome digital camera suggested that a simple illumination source [such as a light emitting diode (LED)] and a detector (such as a photodiode) could be used to monitor colour changes in the sensors. The pK_a of the dye in the solid-phase dye coatings did not vary significantly from that in free solution. There was a linear relationship between the colour intensity of the dye at 573 nm and the log of the NH₃ concentration in the headspace. Whiting, obtained from a local market and stored at room temperature, showed a definite and measurable increase in TVB-N levels between 24 and 30 h. Orange roughy and black scabbard, deepwater fish obtained under known conditions, showed a rise in TVB-N levels between 30 and 45 h when stored at room temperature. Samples stored on ice took 160 to 200 h to achieve similar levels of spoilage.

Keywords: Fish spoilage monitoring; optical ammonia sensor; total volatile bases

A note on the on-farm moist grain storage and feeding practices in Ireland

P. Stacey^1,3†, P. O'Kiely¹, B. Rice² and F.P. O'Mara³

¹ Teagasc, Grange Research Centre, Dunsany, Co. Meath
² Teagasc, Oak Park Research Centre, Carlow
³ Faculty of Agriculture, University College Dublin, Belfield, Dublin 4

This survey was conducted to identify the grain conservation, storage and feeding practices employed for conserving cereals using new technologies for high moisture grains on Irish farms, and the chemical composition at feedout. The mean moisture concentration at harvesting was 336 g/kg and crops were stored anerobically. Forty-three crops were acid-treated and rolled (i.e. crimped) at ensiling while 12 were treated with urea but not rolled. Grain was stored in horizontal silos with a concrete base and sealed beneath black plastic sheeting. The mean level of supplementation was 4.5 kg moist grain per head daily. Digestive upsets were noted when 12 of the crops were fed. It is concluded that the moist grain systems operated satisfactorily on most farms.

Keywords: Cereals; conservation; feeding practices; moist grain; storage