Irish Journal of Agricultural and Food Research Volume 41, Issue 1
The effect of sulphur fertilisation on grass growth and animal performance
M.D. Murphy1, B.S. Coulter1†, D.G. Noonan1 and J. Connolly2
1 Teagasc, Johnstown Castle Research Centre, Wexford
2 University College Dublin, Belfield, Dublin 4
A previous study of S deficiency in Irish grassland was based on cutting trials carried out at 150 locations throughout the country. In order to determine if S deficiency would occur under grazing and affect animal performance, a grazing experiment with beef cattle was carried out on an S-deficient soil between 1981 and 1985. Results showed that when S was applied to pasture, the stock-carrying capacity was increased, especially in late season. Samples of herbage taken prior to each grazing, together with data from a cutting experiment carried out nearby, showed that S fertilisation increased herbage yield by about 20% and also improved herbage quality as measured by its N/S ratio. These factors were probably responsible for the extra stock-carrying capacity of the S-treated areas. Sulphur fertilisation significantly decreased the molybdenum concentration in herbage from 1.85 to 0.87 mg/kg and significantly decreased blood copper of the grazing cattle from 0.56 to 0.49 μg/ml.
Keywords: Cattle; fertiliser; grassland; sulphur
A comparison of four methods of herbage mass estimation
M. O'Donovan1†, P. Dillon1, M. Rath2 and G. Stakelum1
1 Teagasc, Moorepark Research Centre, Fermoy, Co. Cork
2 Department of Animal Science and Production, Faculty of Agriculture, University College Dublin, Belfield, Dublin 4
The objective of this study was to compare the accuracy of four non-destructive techniques for estimation of herbage mass (HM) in swards rotationally grazed by dairy cows. Visual estimation (VE) of HM, a rising plate meter (RPM), the Hill Farm Research Organisation sward stick (SS) and the pasture probe capacitance meter (PPCM) were evaluated. Estimates were obtained on five occasions (July, September and November, 1997 and April and May, 1998). Mean dry matter (DM) yields (kg/ha) of available herbage cut to 40 mm above ground level (AH) and total herbage cut to ground level (TH) were 2161 (s.d. 850.2) and 2762 (s.d. 890.9) kg, respectively. Relationships were obtained for VE, RPM, SS and PPCM with AH, and for RPM, SS and PPCM with TH. For AH, the proportions of variance (R2) accounted for by the model were 0.95, 0.94, 0.92 and 0.72 for VE, RPM, SS and PPCM, respectively. The corresponding residual s.d. values were 193, 222, 249 and 458 kg DM/ha, and the coefficients of variation (CVs) were 9%, 10%, 12% and 21%, respectively. For TH, the R2 values were 0.88, 0.87 and 0.76 for RPM, SS and PPCM, respectively. The corresponding residual s.d. values were 318, 331, and 442 kg DM/ha, and the CVs were 12%, 12%, and 16%, respectively. It is concluded that VE was the most accurate method of HM prediction and that the PPCM method was an inaccurate predictor of HM.
Keywords: Herbage mass; pasture probe; rising plate meter; sward stick; visual assessment
†Corresponding author: maodonovan@moorepark.teagasc.ie.
Simulated bird damage to the plastic stretch-film surrounding baled silage and its effects on conservation characteristics
K. McNamara1 ,2 †, P. O'Kiely1, J. Whelan2, P.D. Forristal3 and J.J. Lenehan1
1 Teagasc, Grange Research Centre, Dunsany, Co. Meath
2 Environmental Resource Management Department, University College Dublin, Belfield, Dublin 4
3 Teagasc, Oak Park Research Centre, Carlow
Two experiments were undertaken to determine the quantitative and qualitative effects of a range of simulated bird damage levels to the plastic stretch-film on the conservation characteristics of baled silage. In each experiment, the plastic stretch- film surrounding 30 bales was subjected to the following levels of damage: none, 1, 10 or 50 small holes, or 1 large hole. The plastic film was removed from the bales after 155 days ensilage and the bales were examined for mould growth, rotted silage, proportionate loss of volume or dry matter (DM), and physical and chemical composition. The bales with 50 small holes and 1 large hole suffered from the greatest amount of mould growth, rotted silage and volume loss. The extent of loss was much greater in Experiment 1 than in Experiment 2, and it is suggested that this was due to the higher DM concentration of the forage in the former experiment. Few significant differences between levels of damage were evident from the qualitative analysis of the cores taken from bales in Experiment 1. In Experiment 2, the edible and inedible portions of each bale were physically separated, and significant (P<0.001) differences were evident between them for most of the qualitative assays. It is concluded that holes similar to those caused by rooks and jackdaws to the plastic stretch-film surrounding baled silage result in potentially serious quantitative and qualitative forage losses, and that bales with high DM concentrations are likely to undergo greater losses than bales with low DM concentrations.
Keywords: Baled silage; conservation characteristics; plastic; simulated bird damage; stretch-film
†Corresponding author: pokiely@grange.teagasc.ie.
Genetic parameters for production and fertility in spring-calving Irish dairy cattle
R.D. Evans1†, F. Buckley1, P. Dillon1 and R.F. Veerkamp2
1 T eagasc, Moorepark Research Centre, Fermoy, Co. Cork
2 I d-Lelystad, PO Box 65, Lelystad, The Netherlands
The objective of this study was to estimate genetic parameters for milk production and selected fertility traits in Irish dairy cattle. Data were derived from 74 seasonal spring-calving dairy herds with a potential cow population of 6,783 in the 1999 calving season. The average 305-day yields (kg) of milk, fat, and protein, the concentrations (g/kg) of fat and protein were 6572, 245, 222, 37.6 and 33.9, respectively. Calving to first service interval (CFS), calving to conception interval (DO) and first service to conception interval (FSCO) averaged 72, 90, and 17 days, respectively, while pregnancy rate to first service (PRFS) and number of services/cow were 0.48 and 1.78, respectively. The proportion of cows conceiving within the first 21, 42, and 63 days after start of breeding (PR21, PR42, and PR63) were 0.36, 0.57 and 0.72, respectively. (Co) variance components were estimated for the complete data set as well as a separate analysis for pedigree and non-pedigree herds within the data set. Heritability estimates, using the complete data set, for milk production traits ranged from 0.22 (±0.042) for milk yield to 0.70 (±0.049) for milk fat concentration while heritability estimates for fertility traits ranged from zero for PR21 to 0.03 (±0.017) for CFS and SBFS (start of breeding to first service interval). Heritability estimates were numerically greater than zero for all fertility traits in the pedigree herd data set with the exception of PR21. Only two fertility traits had heritability estimates for the non-pedigree herds, namely, CFS (0.03±0.030), SBFS (0.03±0.030); analyses for the other fertility traits failed to converge. Genetic correlations between production and fertility traits were mostly antagonistic, for example, correlations between milk yield and number of services (0.98±0.35) and PRFS (-0.51±0.61). Results indicate that selection for yield alone may lead to a deterioration in fertility and that future selection programmes should include some measures of reproductive performance.
Keywords: Fertility; genetic correlation; heritability; seasonal calving
†Corresponding author: revans@moorepark.teagasc.ie
Nutrient utilisation and energy balance associated with two contrasting winter milk production systems for high genetic merit autumn calving dairy cows
C.P. Ferris 1 †, M.A. McCoy 2 , S.D. Lennox 3 , D.C. Catney 3 and F.J. Gordon 1,3
1 A gricultural Research Institute of Northern Ireland, Hillsborough, Co. Down BT26 6DR
2 D epartment of Agriculture and Rural De _e lopment Northern Ireland, Veterinary Science Di _i sion, Stoney Road, Stormont, Belfast BT4 3SD
3 D epartment of Agriculture and Rural Development Northern Ireland, Newforge Lane,Belfast BT9 5PX
Autumn calving dairy cows were managed on two contrasting grassland-based systems of milk production for a full lactation, either high forage (HF) or high concentrate (HC). During the winter, animals on system HF (n=19) were offered grass silage with high feed-value characteristics, supplemented with 5.5 kg/day of concentrate (crude protein concentration 280 g/kg dry matter (DM)) through an out-of-parlour feeding system. Animals on system HC (n=20) were offered grass silage of medium feed-value characteristics, mixed with approximately 14.0 kg/day of (concentrate crude protein 202 g/kg DM in the form of a ‘complete diet’). Animals remained on these winter management systems for a mean of 132 days, with total milk outputs over this period of 3926 (HF) and 4475 (HC) kg. Studies were conducted during this period to examine nutrient utilisation and energy balance associated with each of the two systems. Ammonia nitrogen concentration in rumen liquor was higher with system HF compared to system HC (P<0.01). Urinary energy and nitrogen losses, as a proportion of gross energy and nitrogen intakes, were significantly higher for HF than HC (P<0.001). Minimum energy balance values were –50 (HF) and –33 (HC) MJ/day, while animals reached positive energy balance at 132 (HF) and 84 (HC) days post calving. Diet had a significant effect (P<0.05) on plasma urea, beta-hydroxybutyrate and non-esterified fatty acid concentrations. Fertility for both systems was poor, with proportionally only 0.38 of animals showing commencement of luteal activity within 28 days of calving, while proportion conceiving to first service was 0.26 and 0.21 for systems HF and HC, respectively. Neither blood metabolite concentrations nor energy balance were found to be directly correlated with fertility.
Keywords: Dairy cow systems; energy balance; nutrient utilisation
†Corresponding author: conrad.ferris@dardni.gov.uk.
Influence of transition diets on the performance and metabolic profile of dairy cows both pre- and post-calving
S.T. Butler1 ,2 , J.J. Murphy1†, G.K. Stakelum1, F.P. O'Mara2 and M. Rath2
1 T eagasc, Moorepark Research Centre, Fermoy, Co. Cork
2 D epartment of Animal Science and Production, University College Dublin, Belfield, Dublin 4
The primary objective of this experiment was to compare the effects of ad libitum access to grass silage alone, or to a total mixed ration of grass silage and concentrates for the final 4 weeks of gestation on post-calving production performance. Sixty non-lactating Holstein-Friesian cows were blocked according to expected calving date, body condition score and live weight, and assigned at random to one of four treatments: silage (digestibility 773 g/kg dry matter) only pre-calving followed by a total mixed ration, containing proportionally either 0.35 or 0.55 concentrate, post-calving and a total mixed ration containing proportionally 0.3 concentrate pre-calving followed by a total mixed ration, containing proportionally either 0.35 or 0.55 concentrate, post-calving. Individual dry matter intake was measured at approximately 16 days pre-calving and 23 days post-calving. Blood samples were taken from the coccygeal vessels at the start of the experiment, at calving, and at 2 and 4 weeks post-calving to assess energy and protein status. There was no interaction between pre- and post-calving treatments. Post-calving milk yield (22.7 v. 23.3 kg/day, s.e.d. 1.01), milk protein concentration (33.4 v. 33.3 g/kg, s.e.d. 0.49), milk fat concentration (43.6 v. 43.3 g/kg, s.e.d. 1.06), daily live-weight loss (0.68 v. 0.57 kg, s.e.d. 0.146) and weekly body condition score loss (0.08 v. 0.09, s.e.d. 0.014) were not affected by pre-calving feeding treatment. Pre-calving dry matter intakes were not significantly different between treatments (8.1 kg/day for silage only v. 9.2 kg/day for total mixed ration, s.e.d. 0.66). At 2 weeks post-calving, blood metabolites indicated a superior nutritional status for the animals on the total mixed ration pre-calving. There was a significant increase in production performance with higher concentrate proportion post-calving. In this study post-calving performance was not improved by concentrate supplementation during the 4 weeks before parturition when the available forage was of high quality.
Keywords: Concentrate supplementation; dairy cows; transition feeding
†Corresponding author: jmurphy@moorepark.teagasc.ie.
Immunological and haematological responses in calves supplemented with organic chromium and offered different calf milk replacers
B. Earley†, R.J. Fallon, M. Murray and J.A. Farrell
Teagasc, Grange Research Centre, Dunsany, Co. Meath
Holstein x Friesian calves (n=100), purchased at auction marts at about 21 days of age, were used to investigate the effects of supplementation with organic chromium on mitogen-induced blastogenesis of isolated peripheral blood mononuclear cells and specific haematological variables. Calves were allocated randomly to one of five different milk replacers; skim milk, whey-based soyabean isolate Brand A, whey-based soyabean isolate Brand B, whey-based enzyme processed soya Brand C, and wheybased enzyme processed soya Brand D. Within each milk replacer treatment, 10 calves received a daily supplementation of organic Cr equivalent to 250 mg/kg dry matter intake. Neither average daily gain or the required frequency of antibiotic treatments were affected by Cr supplementation or type of calf milk replacer. Following supplementation with organic Cr for 63 days no significant changes were detected between treatments in plasma cholesterol, glucose, triacylglycerol (TRIG), high density lipoprotein (HDL), low density lipoprotein LDL , non-esterified fatty acids (NEFA), beta-hydroxy butyrate (BHB), total white cell counts (TWC), granulocyte numbers, monocyte numbers or lymphocyte numbers. Plasma creatinine concentration was significantly higher (P<0.05) in the unsupplemented calves compared to those supplemented with Cr. Cr supplementation enhanced the lymphocyte blastogenic response in healthy calves but had no major effect on physiological responses irrespective of the type of calf milk replacer that was offered.
Keywords: Cellular immunity; chromium; humoral immunity; lymphocyte blastogenesis
†Corresponding author: bearley@grange.teagasc.ie.
The effects of energy and lysine concentrations in grower diets for pigs on performance from 8 to 12 weeks of age
R.N. Weatherup1, V.E. Beattie1†, K.J. McCracken2, R.W. Henry3, S.G. McIlroy4 and S. Smyth4
1 A gricultural Research Institute of Northern Ireland, Hillsborough, Co. Down BT26 6DR
2 D epartment of Agriculture for Northern Ireland, Newforge Lane, Belfast BT9 5PX
3 D evenish Nutrition Ltd., 96 Duncrue Street, Belfast BT3 9AR
4 J ohn Thompson & Sons Ltd., 35-39 York Road, Belfast BT15 3GW
Two trials were conducted to examine the effects of offering diets with a range of energy and lysine concentrations on the performance of growing pigs from 8 weeks of age for a period of 28 days. Cereal/soya diets were formulated to contain 15.5, 14.4, 13.4 and 12.4 MJ digestible energy (DE)/kg with either 226 (high) or 194 (low) g crude protein/kg in a 4 × 2 factorial arrangement of treatments. Diets were offered ad libitum to 192 individually-housed pigs (Trial 1) and to 1317 group-housed pigs in groups of approximately 20 (Trial 2). In the finishing phase, all pigs were offered the same commercially available diet over a 9-week period. There were no significant interactions between dietary energy and lysine concentration on growth performance. At the lower energy concentrations, feed intake increased (P<0.001) but DE intake was reduced (P<0.001) in Trial 1. Live-weight gain (g/day) was similar at all energy concentrations. In Trial 2, pigs had similar feed intakes at all energy concentrations with the result that DE intake, daily live-weight gain and feed conversion ratio were poorer (P<0.001) at the lower energy concentrations. Growth performance was not adversely affected by reducing lysine concentration in either trial.
Keywords: Energy; group housing; growth performance; lysine; pigs; protein
†Corresponding author: violet.beattie@devenishnutrition.com
Seasonal effects of some milk powder characteristics on the rheology of milk chocolate
M. Twomey1, M.K. Keogh1†, B.T. O'Kennedy1 and D.M. Mulvihill2
1 T eagasc, Dairy Products Research Centre, Moorepark, Fermoy, Co. Cork
2 F ood Chemistry, Department of Food Science and Technology, University College, Cork
The relationships between some spray-dried high-fat milk powder properties and the rheology of milk chocolate at the end of conching, and its final hardness were determined. Eleven spray-dried high-fat milk powders with free-fat concentrations of 40 to 96 g/100 g fat, solid fat concentrations at 10 °C of 39 to 56 g/100 g, powder median particle sizes of 28 to 66 μm and vacuole volumes of 0 to 3.9 ml/100 g powder, were blended with skim-milk powders to give an ingredient with 26 g fat/100 g for chocolate manufacture. The Casson viscosity (Pa s) of the chocolate, at 40 °C at the end of conching, decreased as the free-fat concentration increased (P<0.01) and as the powder median particle size increased (P<0.05). The Casson yield value at 40 ºC at the end of conching decreased by 9.7 Pa (P<0.01) as the solid fat concentration increased. The hardness of the tempered milk chocolate was significantly reduced as the free-fat concentration increased (P<0.05) and as the particle size increased (P<0.05). The validity of the models generated was confirmed using five additional milk powders to make five milk chocolates. It was concluded that spray-dried high-fat milk powders with different properties can be used to make chocolates with a range of viscosities and yield values for different end uses, such as moulding or enrobing.
Keywords: Chocolate rheology; milk powder composition; seasonality
†Corresponding author: kkeogh@moorepark.teagasc.ie.
Mycobacterium avium subsp. paratuberculosis in pasteurised and unpasteurised milk in the Republic of Ireland
A. O’Doherty 1 , D. O’Grady 1 , T. Smith 2 a nd J. Egan1†
1 Central Veterinary Research Laboratory, Abbotstown, Castleknock, Dublin 15
2 National Diagnostic Centre, BioResearch Ireland, National Uni_ersity of Ireland, Galway
Between March and September 1999, 310 milk samples were collected from individual compartments of bulk tankers on their arrival into seven dairy co-operatives. In addition, 77 cartons of pasteurised cows milk from eight dairies and nine cartons of pasteurised goat’s milk from two dairies were purchased from retail outlets during the same period. Following decontamination with hexadecyl pyridinium chloride, the samples were cultured for Mycobacterium avium subsp. paratuberculosis (Map) using Bactec B12B and Herrold’s Egg Yolk medium. All 396 samples tested negative for culture of Map. Non-mycobactin dependant mycobacteria were isolated from 12 of the unpasteurised samples.
Keywords: Milk; Mycobacterium a_ium subsp. Paratuberculosis
