Effects of applying sodium and sulphur fertilisers on the concentrations of elements in water leached from permanent pasture

The element composition of water leached from a perennial ryegrass pasture to which isonitrogenous quantities of sodium nitrate, ammonium nitrate or ammonium sulphate fertilisers had been applied in an experiment lasting 2 years is described. The experimental design also allowed a comparison of the immediate effects of sodium nitrate in the grazing season in which the fertiliser was applied with the residual effects of applying it in the previous year. Applying sodium fertiliser in either 1992 or 1993, but not both years, increased the concentrations of sodium, potassium, magnesium, calcium and cobalt and reduced those of phosphorus and molybdenum in leachate. The application of sulphur fertiliser reduced the concentrations of zinc, copper, iron and molybdenum in leachate. It also reduced the concentrations of sodium, potassium and magnesium, but only when sodium fertiliser was applied in 1992, and not when it was applied in 1993. It is concluded that sulphur fertiliser reduces the leaching of trace elements from the soil and that, in the long term, sodium fertiliser can amplify the effect of applying sulphur fertiliser. Sodium fertiliser in moderate quantities increased the leaching of the major divalent cations but reduced the phosphorus and molybdenum concentrations in leachate. © 2002 Society of Chemical Industry     

Effects of sodium and sulphur fertilisers on the concentrations of nitrate and potentially toxic elements (PTEs) in water leached from permanent pasture

The concentrations of nitrate and potentially toxic elements (PTEs) are reported in water leached from a perennial ryegrass pasture to which isonitrogenous quantities of sodium nitrate, ammonium nitrate or ammonium sulphate fertilisers had been applied in an experiment lasting 2 years. The experimental design allowed a comparison of the immediate effects of sodium nitrate in the grazing season in which the fertiliser was applied with the residual effects of applying it in the previous year. Leachate composition was monitored from December of the first year to August of the second year. Sodium fertiliser reduced the concentrations of cadmium in soil and leachate, but it increased lead concentration in soil and reduced it in leachate. Sulphur fertiliser had no effect on any PTE. Nitrate concentration in leachate increased towards the end of the winter to almost reach the EU legal limit in water and then declined during the spring and summer. Sodium fertiliser applied in either but not both years reduced nitrate concentration. Sulphur fertiliser had varied effects on nitrate concentration in leachate depending on the timing of sodium fertiliser application. When applied at the same time as sodium fertiliser, sulphur fertiliser decreased nitrate concentration, but when applied to areas that had received sodium fertiliser in the previous year, it increased nitrate concentration. It is suggested that sodium fertiliser residues may have long‐term effects on leachate nitrate concentration that determine the impact of sulphur fertilisers. It is concluded that sodium fertilisers may reduce the concentrations of at least two PTEs, cadmium and lead, in ground water and that the effects of sulphur fertilisers are dependent on the sodium status of the soil. © 2002 Society of Chemical Industry     

Dairy soil bacterial responses to nitrogen application in simulated Italian ryegrass and white clover pasture

Through clearing and use of fertilizer and legumes, areas of southwestern Australia's unique coastal sand plains can support relatively low-cost dairies. However, the ancient, highly weathered nature of the soils in this region makes the dairies susceptible to a range of threats, including nutrient leaching and erosion. Despite this, Western Australian dairy cows typically produce up to 5,500 L of milk per head annually supported by inorganic nitrogen (N) fertilizer (commonly 50:50 urea and ammonium sulfate) at rates up to <320 kg of N/ha per year. Where hotspots exist (up to 2,000 kg of N/ha per year), total N exceeds pasture requirements. We investigated plant and soil bacteria responses to N fertilizer rates consistent with Australian legislated production practices on dairy farms for pure and mixed swards of white clover (Trifolium repens) and Italian ryegrass (Lolium multiflorum) in a long-term pasture experiment in controlled glasshouse conditions. Although the soil bacterial community structure at phylum level was similar for white clover and Italian ryegrass, relative abundances of specific subgroups of bacteria differed among plant species according to the N fertilizer regimen. Marked increases in relative abundance of some bacterial phyla and subphyla indicated potential inhibition of N cycling, especially for N hotspots in soil. Ammonium concentration in soil was less correlated with dominance of some N-cycling bacterial phyla than was nitrate concentration. Changes in bacterial community structure related to altered nutrient cycling highlight the potential for considering this area of research in policy assessment frameworks related to nutrient loads in dairy soils, especially for N.     

Effects of providing total mixed rations indoors and on pasture on the behavior of lactating dairy cattle and their preference to be indoors or on pasture

Grazing is considered a normal behavior for dairy cattle, although they may not be able to meet their nutritional requirements from grazing alone, and so to sustain higher yields requires access to a total mixed ration (TMR). The study aim was to provide dairy cows with access to TMR indoors and on pasture to establish influence on behavior and preference for each location. The study took place from August to November, 2009, using 36 late-lactation Holstein-Friesian dairy cows. The cows were allocated to 1 of 3 26-d study periods (n = 12 × 3). Within each period the cows were further divided into a control (n = 6) or treatment (n = 6) group using a crossover design, where the cows were changed between the control and treatment group after 13 d. Treatment cows had access to TMR indoors and on pasture, whereas control cows only had access to TMR indoors. Following a.m. and p.m. milkings the cows were taken to a point equidistant between indoors and pasture and given the choice of going to pasture (1.5 ha) or to a freestall barn. Between milkings the cows had free access between the locations. Initial choice was recorded and a video camera was used to record time spent in each location. Behavior observations were recorded to establish how the cows spent their time during the day. To determine what factors influenced preference, weather conditions, milk yield, body condition score, and lameness were recorded. Initially, the cows chose indoors following milking (96.4 ± 0.80%). Overall, the cows expressed a partial preference for pasture (71.1 ± 1.82%), which was different from 100, 50, and 0%. Study period influenced preference with cows spending less time on pasture as the season progressed (86.7 vs. 68.3 vs. 58.3% for study periods 1, 2, and 3, respectively). Providing the cows with TMR outdoors did not affect pasture use, but resulted in an increase in TMR intake of 2.2 ± 0.41 kg of dry matter/d. The cows spent more time on pasture as the temperature-humidity index indoors (55.6 ± 0.92) and outdoors (54.6 ± 0.82) increased, but rainfall and milk yield did not influence preference. Cows with lameness score >1.5 spent more time indoors (35.4 ± 4.52 vs. 25.2 ± 2.64% for cows with >1.5 vs. ≤1.5 lameness score, respectively). In conclusion, the cows expressed a partial preference for pasture, which was not influenced by providing TMR on pasture.     

Restricting daily time at pasture at low and high pasture allowance: Effects on pasture intake and behavioral adaptation of lactating dairy cows

In pasture-based dairy systems, daily time at pasture is restricted during several periods of the year. The aim of this experiment was to evaluate the effect of restricting time at pasture on milk yield, pasture dry matter (DM) intake, and grazing behavior of dairy cows according to pasture allowance (PA), which partly defines pasture availability. The experiment was carried out in spring on strip-grazed perennial ryegrass pastures. The 6 treatments consisted of 3 durations of daily time at pasture [U: unrestricted day and night grazing (22 h at pasture); R9: 1 grazing session restricted to 9 h between the 2 milkings; R5: 2 grazing sessions of 2.75 h after each milking) compared at low and high PA (13 and 24 kg of DM/d per cow >5 cm, respectively). Eighteen mid-lactation Holstein dairy cows were used according to a 6 × 4 incomplete Latin square design replicated 3 times with four 14-d periods. Pasture DM intake was measured by the ytterbium-fecal index method and grazing behavior from portable devices. On average, restricting time at pasture from U to R (mean of R5 + R9) decreased pasture intake by 2.9 kg of DM, milk yield by 1.3 kg, and milk protein concentration by 0.11%, and increased milk fat concentration by 0.20%. Pasture intake and milk yield did not differ significantly between R9 and R5. The reduction of pasture intake and milk yield with decreasing time at pasture was greater at high compared with low PA. Grazing times were 536, 414, and 305 min, representing proportions of time spent grazing of 0.40, 0.77, and 0.93 for treatments U, R9, and R5, respectively. The reduction of grazing time with decreasing time at pasture was greater at high compared with low PA. Pasture intake rate greatly increased with decreasing time at pasture, but mainly on R5 (29.8, 31.6, and 42.1 g of DM/min for U, R9, and R5, respectively). The effect of time at pasture on pasture intake rate was unaffected by PA. In conclusion, the effect of restriction of time at pasture on pasture intake and milk yield becomes more marked as PA increases. Cows offered only 2 grazing sessions of 2.75 h after each milking maximized pasture intake rate and consumed pasture as much as in one 9-h grazing session.     

Effects of grazing and nitrogen fertiliser on the soil microbial biomass under permanent pasture

Carbon and nitrogen in the soil microbial biomass were measured on eight occasions during a grassland production season, under swards of perennial ryegrass receiving 210 or 420 kg N ha^?1 per year or of ryegrass/white clover receiving no fertiliser N. The swards were either cut or grazed at monthly intervals. Soil microbial biomass C increased under all treatments in late April before declining until late July and rising slowly towards the end of the season. Values for microbial C under cutting and grazing were not significantly different but were usually larger under grass/clover than under grass. In contrast, the smallest values for soil microbial biomass N were recorded in late April. Larger N values were again recorded under grass/clover, and although values were nearly always smaller under grazing than under the corresponding cut treatment the differences were not significant. Soil biomass N comprised a large reservoir of mobile N, and at any one time contained 11, 3 and 5 times more N than was present in the mineral N component of the soil, the standing crop or excretal returns, respectively. It did not appear to be responsive, within a season, to the considerable returns of C and N from grazing animals or to N fertiliser management.     

硫磺熏蒸前后银耳中6种有害金属元素的变化研究

通过在实验室模拟硫磺熏蒸的手段,采用微波消解电感耦合等离子体质谱法（ICP-MS）对硫磺熏蒸前后银耳中铅、砷、汞、镉、铬、铜6种有害金属含量进行测定。结果表明,随着熏蒸时间的增加,经过硫磺熏蒸的银耳砷的含量显著提高,汞含量也有一定程度的上升,而其他4种元素没有明显变化。硫磺熏蒸作为一种食品处理方法,其对食品品质的影响及安全性有待进一步的考量。      

Oxidation and transformation of elemental sulphur in soils

The oxidation of ³⁵S-S⁰ (³⁵S-S⁰, sulphur flowers) added to four cultivated soils was well described using first-order kinetics. The half-life (t_l/2) of ³⁵S-S⁰ ranged from 12 days in a paddy soil to 176 days in an Ultisol. During the early phase of oxidation, a large proportion of the oxidised S was incorporated into organic fractions. After the first week any additional ³⁵S-S⁰ oxidised remained primarily as SO-S in most of the test soils. The amount of KH₂PO₄- extractable ³⁵S-SO-S as a percentage of total oxidised ³⁵S-S was at a maximum when approximately half of the added ³⁵S-S⁰ was oxidised. By the end of the 56-day incubation period, with the exception of the Ultisol, 54–70% of the oxidised ³⁵S-S in the test soils was present as ³⁵S-SO-S. The remaining oxidised S is presumed to have been converted into organic matter fractions. This ³⁵S-organic-S could be fractionated into the 0.1 M KH₂PO₄-extractable organic- S (5–13% of total oxidised ³⁵S-S) and the 0.01 M NaOH-extractable organic-S (14–23% of total oxidised ³⁵S-S). With the exception of the Ultisol where the undetermined organic S was about 36%, the amounts of unaccounted for S (not directly measured), in all soils were very small (typically less than 4%).     

Grazing season length and stocking rate affect milk production and supplementary feed requirements of spring-calving dairy cows on marginal soils

The objective of this study was to investigate the effect of increasing stocking rate (SR) and extending grazing season (GS) length on pasture and animal productivity on a marginal, poorly draining soil type. The study was a multiyear (2017 to 2020, inclusive) whole farm systems evaluation with a 2 × 2 factorial experimental arrangement of treatments. The systems evaluated comprised 2 GS lengths, average (AGS; 205 d) and extended (EGS; 270 d), and the 2 whole farm stocking rates were medium (2.5 cows/ha) and high (2.9 cows/ha). We used this study design to create 4 grazing system intensities (500, 600, 700, and 800 cow grazing days per hectare per year). In 2017, cows were randomly allocated to 1 of the 4 whole farm systems precalving and remained on the same treatments for the duration of the study. We found no significant differences in total average annual pasture production [14,133 ± 538 kg of dry matter (DM) per hectare] or sward chemical composition between GS and SR treatments over the 4-yr period, with the exception of average crude protein content, which was lower for EGS (211 g/kg DM) compared with AGS (218 g/kg DM). Grazed pasture production was significantly increased in EGS treatments (+758 kg of DM/ha) compared with AGS (9,917 kg of DM/ha), whereas conserved silage DM production was greater for AGS (+716 kg of DM/ha) compared with EGS (3,583 kg of DM/ha). Neither GS nor SR had a significant effect on daily or cumulative lactation milk and fat plus protein production per cow (5,039 and ±440 kg, respectively). Increasing SR resulted in increased milk fat plus protein yield per hectare based on increased grazed pasture utilization. These results add further credence to the important additive contributions of both extended grazing and SR intensification to achieve high levels of grazed pasture utilization and milk production per hectare while reducing supplementary feed requirements within spring-calving grazing systems.     

Responses of breadmaking quality to sulphur in three wheat varieties

Field experiments were carried out at three sites in England to investigate the effects of S fertilisation on breadmaking quality of three winter wheat varieties (Hereward, Rialto and Spark) in the 1996–1997 season. The soils at the three sites differed in extractable S contents. Depending on site, either 180 and 230 kg ha⁻¹ N or 230 and 280 kg ha⁻¹ N treatments were factorially combined with three S treatments (0, 20 and 100 kg ha⁻¹ S). Addition of S increased loaf volume significantly at two sites where grain S concentration was also significantly increased and grain N:S ratio decreased. Application of the extra 50 kg ha⁻¹ N increased grain protein concentration but did not increase loaf volume at any of the sites. Loaf volume was found to correlate more closely with grain S than with grain protein concentration. Addition of S generally decreased the elastic modulus of gel protein and dough resistance but increased dough extensibility. Despite considerable differences in their dough rheology, the responses in rheology and loaf volume to S were similar in all three varieties. Selected flour samples of Rialto from the Bridgets site were also analysed for the glutenin subunit distribution, showing that S addition increased the relative proportion of low-molecular-weight subunits at the expense of high-molecular-weight subunits of glutenin. This study therefore shows that the beneficial effects of S on breadmaking quality are associated with decreased dough elasticity and increased extensibility resulting from effects on the amount and composition of the glutenin polymers. The results also indicate that S fertilisation is required in some areas of England to maintain breadmaking quality. © 1999 Society of Chemical Industry     

The effect of carbohydrate source on nitrogen capture in dairy cows on pasture

The objective of this study was to determine if feeding carbohydrate supplements with faster degradation rates than corn to dairy cows grazing ryegrass would improve nitrogen capture, milk production, and components. Treatments were grain supplements based on: 1) corn (CORN), 2) barley and molasses (BM), or 3) citrus pulp and molasses (CM). For BM and CM, the diet composition was the same as that of CORN except that a portion of the corn was replaced with barley and molasses or citrus pulp and molasses, respectively, on a dry matter basis. Cows grazed ryegrass (Lolium multiflorum Lam.) pasture. Yield of milk, 3.5% fat-corrected milk, energy-corrected milk, and milk fat, as well as milk fat percentage, were not different among treatments. True milk protein percentage was higher for CORN (2.81%) compared with CM (2.70%), but was not different for BM (2.77%). However, true milk protein yield was not different among treatments. Milk urea N was higher for BM (11.43 mg/dL) compared with both CORN and CM (average: 9.95 mg/dL). There were no differences among CORN, BM, and CM treatments for overall BUN (average: 10.60 mg/dL). At 0400 h, however, cows on CORN had higher BUN than cows on CM (11.43 vs. 9.96 mg/dL), but there were no differences between CORN and BM (average: 11.21 mg/dL) or BM and CM (average: 10.48 mg/dL), and there were no differences among treatments at other time points. The CM diet might have shown more advantage if the pasture crude protein content was higher. Partial replacement of corn with citrus pulp for grazing cows should be further studied using pasture with higher crude protein content. Although cows receiving CM and BM did not produce more milk than cows on CORN, if barley or citrus pulp is less expensive than corn, they may be viable replacements for a portion of the corn supplement for grazing cows.     

Meta-analysis of the effect of pasture allowance on pasture intake,milk production,and grazing behavior of dairy cows grazing temperate grasslands

Daily pasture allowance (PA) is defined as the product of pregrazing pasture mass and offered area, and is the major grazing management factor determining pasture utilization per unit area and daily performance of grazing dairy cows. The objective of the present study was to perform a meta-analysis reviewing the effect of PA on pasture intake, milk production, milk composition, and grazing behavior of dairy cows. Experiments studying the effect of PA on pasture intake or milk production, which eventually included milk composition or grazing behavior data, or both, were selected to create a database. Papers were selected only if at least 2 PA were compared under the same experimental conditions, particularly the same pasture mass (i.e., where PA levels were only obtained through changes in daily offered area). The final database included 97 PA comparisons reported in 56 papers. For analytical purposes, the database was subdivided into 3 subsets that varied according to the estimation height (EH) at which PA was determined; that is, PA above ground level (PA₀ subset), PA above 2.5 to 3.5 cm (PA₃ subset), and PA above 4 to 5 cm (PA₅ subset). Statistical analyses were conducted independently on the PA₀, PA₃, and PA₅ subsets and on the whole database (global analysis) by using linear and nonlinear mixed-model procedures. The curves, either exponential, quadratic, or linear, describing the effects of PA on pasture intake, milk production, or grazing behavior of dairy cows are conceptually similar, whatever the EH. The equations describing these curves are, however, specific for each EH. Accordingly, from typical low to high PA, the increase in pasture intake (0.13 vs. 0.21 vs. 0.28 kg/kg of PA), milk production (0.11 vs. 0.17 vs. 0.24 kg/kg of PA), and milk solids production (0.008 vs. 0.010 vs. 0.013 kg/kg of PA) per kilogram of increase in PA was lower for PA₀ than for PA₃, and for PA₃ than for PA₅. Grazing time increased from low to medium PA and did not vary from medium to high PA. Pasture intake rate seemed to increase from low to medium PA because of greater bite mass, whereas it increased from medium to high PA because of greater biting rate. The present meta-analysis demonstrated that the general relationship between PA and any dependent variable is quite strong and independent of EH. This suggests no specific relationship for some parts of the world or methodology approach, with a high portability of the global equations calculated here. These results are useful for improving grazing management and modeling on pasture-based dairy systems.     

A comparison of three strains of holstein-friesian grazed on pasture and managed under different feed allowances

This experiment compared Holstein-Friesian (HF) cows of New Zealand (NZ) origin representative of genetics present in the 1970s (NZ70; n = 45) and 1990s (NZ90; n = 60), and a group of HF cows of North American origin with 1990s genetics (NA90; n = 60), which were managed in grazing systems with a range of feeding allowances (4.5 to 7.0 t/cow per yr) over 3 yr. The NZ70 cows had the lowest Breeding Worth genetic index and the lowest breeding values for yields of fat, protein, and milk volume; the NZ90 and NA90 cows were selected to have similar breeding values for milk traits and were representative of cows of high genetic merit in the 1990s. The NZ90 cows had a higher milk protein concentration (3.71%) than either the NA90 (3.43%) or the NZ70 cows (3.41%), and a higher milk fat concentration (4.86%) than the NA90 cows (4.26%) with a level similar to the NZ70 cows (4.65%). The NZ90 cows produced significantly greater yields of fat, protein, and lactose than the NA90 and NZ70 cows. The NZ70 cows had the lowest mean annual body weight (473 kg) but the highest body condition score (BCS; 5.06). Days in milk were the same for the 2 NZ strains (286 d in milk), both of which were greater than the NA90 cows (252 d in milk). There was no genotype × environment interaction for combined milk fat and protein yield (milksolids), with NZ90 producing 52 kg/cow more than the NA90 at all feeding levels. The NZ70 strain had the highest seasonal average BCS (5.06), followed by the NZ90 (4.51) and the NA90 (4.13) strains on a 1 to 10 scale. Body condition score increased with higher feeding levels in the 2 NZ strains, but not in the NA strain. The first-parity cows commenced luteal activity 11 d later than older cows (parities 2 and 3), and the NA90 cows commenced luteal activity 4 and 10 d earlier than the NZ70 and NZ90 cows. Earlier estrus activity did not result in a higher in-calf rate. The NZ70 and NZ90 cows had similar in-calf rates (pregnancy diagnosed to 6 wk; 69%), which were higher than those achieved by NA90 cows (54%). Results showed that the NA90 strain used in this experiment was not suitable for traditional NZ grazing systems. Grazing systems need to be modified if the NA90 strain is to be successfully farmed in NZ. The data reported here show that the NA90 cows require large amounts of feed, but this will not prevent them from having a lower BCS than the NZ strains. Combined with poor reproductive performance, this means that NA90 cows are less productive than NZ HF in pasture-based seasonal calving systems with low levels of supplementation.     

Udder measurements and milk production in two Awassi sheep genotypes and their crosses

To improve the effectiveness of community-based breeding programs for increased milk production, the values of different udder measurements for predicting milk production traits during the milking period were assessed over 3 yr on 273 Awassi ewes. Machine milking of ewes began after weaning, 56 d after parturition, and continued until the milk yield of the ewes was <200 mL/d. Milk yield obtained by hand milking and milk composition were measured weekly, and days in milk, total milk yield, and total yields of protein, fat, and nonfat solids in milk were calculated for each ewe. On d 70 of milking, morphological traits of the whole udder (circumference, width, height, and length), udder cistern (height), and teats (length, width, and position score) were measured. On the same day, the milk yield of ewes was recorded by hand milking. Positive and moderate to strong correlations (r = 0.36 to 0.76) between udder circumference and width, teat width, and milk production traits of total milk yield, and total yields of protein, fat, and nonfat solids were found. However, a more accurate predictor of milk production traits was milk yield on d 70, as higher positive correlations between this variable and the milk production traits were found (r = 0.63 to 0.89). Nine farmers were invited to independently estimate the hand-milked milk yield performance of a sample of 169 ewes (d 15 to 45 of milking) by visually observing each ewe and making a subjective linear score (1 to 5). Their assessments were significantly correlated with milk yield on the day of the observation (r = 0.52), total milk yield (r = 0.50), and days in milk (r = 0.45). Considering the perception details provided by farmers concerning each of the subjective linear scores, it was found that most predictive linear udder measurements of udder circumference and width and teat width identified in this study were implicit in these scores. The predictive ability of the measurements studied have practical implications for community-based breeding programs involving improvement of milk production—not just in Syria, but in other countries in dry areas as well—because it is possible for experienced farmers to visually assess milk production of dairy ewes or take simple udder measurements with predictive value.     

The effect of pasture allowance and supplementation on feed efficiency and profitability of dairy systems

Partial budgeting was used to compare income over feed costs of high-yielding Holstein cows based on data from an experiment with 4 dietary treatments arranged in a 2 x 2 factorial. The factors were low (25 kg DM/cow per day) and high (40 kg DM/cow per day) pasture allowance (PA) and supplemental grain fed at 1 kg/4 kg of milk or no supplemental grain fed. The 4 treatments were low PA unsupplemented (LPAU), low PA concentrate supplementation (LPAC), high PA unsupplemented (HPAU), and high PA concentrate supplementation (HPAC). Two management systems were modeled. The first, a fixed herd size flexible rotation length model, and the second, a flexible herd size model where rotation length was fixed. The LPAC treatment yielded the highest income over feed costs, followed by the HPAC treatment. The treatment generating the lowest income was the HPAU system. The low PA systems generated more income than did the high PA systems for equivalent supplemental feeding strategies. The results also showed that feeding supplemental grain increased the income-over-feed costs compared with systems that did not feed supplemental grain. In most treatments, comparing the fixed herd against the flexible herd models, the flexible herd size model generated higher income due to the substitution of relatively low income per hectare of hay production for higher income from milk production. There were also differences in feed conversion efficiencies for milk production due to concentrate supplementation (1.04 unsupplemented vs. 1.21 supplemented), but PA did not affect the efficiency of milk production. Neither supplementation nor PA affected the feed conversion efficiency of milk fat yield. However, the efficiency of milk protein yield was affected by concentrate supplementation (0.028 unsupplemented vs. 0.034 supplemented) but not by pasture allowance.     

Influence of packaging film permeability and residual sulphur dioxide on the quality of pre-peeled potatoes

The effects of sodium bisulphite concentration and gas permeability of the packaging film on the surface colour, texture, exudate production and microbial growth of pre-peeled refrigerated potatoes were evaluated to determine shelf-life and the lowest level of preservative which could be used.
The product was packaged in polyethylene film, or in vacuo , using EVA-SARAN-EVA laminate and stored refrigerated. Polyethylene was not adequate in several aspects; packaging in oxygen barrier film allowed reduction of bisulphite levels, and vacuum packaging of 50 ppm bisulphite treated samples doubled the shelf-life of the product compared with aerobic packaging.     

Effect of restricted access time to pasture on dairy cow milk production, grazing behavior, and dry matter intake

The objective of this experiment was to investigate the effect of restricting pasture access time on milk production and composition, body weight and body condition score change, dry matter intake, and grazing behavior of autumn calving dairy cows in midlactation. Fifty-two (19 primiparous and 33 multiparous) Holstein-Friesian dairy cows (mean calving date, August 17 ± 91.2 d) were randomly assigned to a 4-treatment (n = 13) randomized block design grazing study. The 4 grazing treatments were: (i) full-time access to pasture (22H; control), (ii) 9-h access to pasture (9H), (iii) two 4.5-h periods of access to pasture after both milkings (2 × 4.5H), and (iv) two 3-h periods of access to pasture after both milkings (2 × 3H). Experimental treatments were imposed from March 7 to April 6, 2007 (31 d). The pregrazing herbage mass of swards offered to all treatments was 1,268 kg of dry matter/ha, and sward organic matter digestibility was 86.4%, indicating high-quality swards conducive to high dry matter intake. Swards where animals had 22H and 2 × 4.5H access to pasture had the lowest postgrazing sward heights (3.5 cm), reflecting the greatest levels of sward utilization. After the experimental period, there were no differences in milk production; however, the 2 × 3H animals tended to have lower milk protein concentration (−0.17%) compared with 22H animals. Furthermore, dry matter intake of the 9H animals was lower than 22H animals. Although restricting access time to pasture decreased grazing time, animals compensated by increasing their intake/minute and intake/bite. Restricting pasture access time resulted in much greater grazing efficiency, because the 9H, 2 × 4.5H, and 2 × 3H treatments spent a greater proportion of their time at pasture grazing (81, 81, and 96%, respectively) than 22H animals (42%). Results of this study indicate that allocating animals restricted access to pasture does not significantly affect milk production. This study also found that the total access time should be greater than 6 h and that perhaps needs to be divided into 2 periods.     

The effects of spring feeding strategy on pasture productivity,sward quality,and animal performance within intensive pasture-based dairy systems

The objective of this research was to evaluate how different feeding strategies based on various pasture availability (PA) treatments within intensive seasonal production systems affected pasture production and utilization, sward quality, and the milk production, body weight (BW), and body condition score (BCS) of dairy cows. The performance data were obtained from a 3-yr experiment conducted previously (2018–2020, inclusive). In total, records from 208 spring-calving dairy cows were available for analysis. The animals were randomly allocated to 1 of 3 PA grazing treatments in spring that varied in average pasture cover (measured as herbage mass available above 3.5 cm) that was established via different pasture management strategies in the previous autumn. Thus, the opening average pasture cover across all paddocks on February 1 was 1,100 kg of dry matter (DM)/ha for high pasture availability (HPA), 880 for medium pasture availability (MPA), and 650 for low pasture availability (LPA), respectively. The measurements were taken over an 8-wk period during the first grazing rotation in spring, commencing on February 16 (±2 d) and finishing when all paddocks were grazed once on April 12 (±5 d). Paddocks that were part of the HPA treatment showed the highest pregrazing herbage masses and pregrazing sward heights (1,645 kg of DM/ha and 8.2 cm, respectively) compared with MPA (1,412 kg of DM/ha and 7.5 cm, respectively) and LPA (1,170 kg of DM/ha and 6.9 cm, respectively). Owing to the differences in PA, daily herbage allowance was greatest for HPA (11.7 kg of DM/cow), intermediate for MPA (10.2 kg of DM/cow), and lowest for LPA (8.8 kg of DM/cow), with the remaining feed deficit composed of additional daily grass silage supplementation (0.8, 1.5, and 2.8 kg of DM/cow for HPA, MPA, and LPA, respectively), while the daily concentrate and daily total feed allowance were equal between treatments during spring (2.7 and 15.0 kg of DM/cow). Despite salient differences in fresh pasture used, complementing pasture intake with grass silage did not affect daily or cumulative milk, solids-corrected milk, fat, or protein yield or milk constituents. Similarly, BW and BCS were also unaffected by PA treatment. The results highlight the importance of high spring pasture utilization and grazing efficiency achievable with higher pregrazing herbage masses, which also allow larger animal intakes from grazed pasture as the cheapest feed source during spring. Moreover, targeting an adequate pasture supply at the commencement of calving increases the grazing days per hectare and lowers the requirement for supplementary feed on farm, particularly when facing increasing variability in climatic conditions.     

Effect of long-term application of animal slurries to grass on silage feeding quality for sheep

The effect of slurry type (pig or cow) and use of a bacterial silage inoculant, was assessed on herbage from long-term slurry plots ensiled in pilot-scale (0·7 tonne) silos. Silage was fed to sheep to assess digestibility and metabolisable energy content. The latter was measured by direct calorimetry in a modified cattle respiration chamber. Non-inoculated slurry-treated silages had poorer fermentation quality than inoculant-treated silages (P < 0·001) and silages treated with cow slurry had poorer fermentation quality than those treated with pig slurry (P < 0·001). Digestibility values for different components of the silages showed few differences. Energy digestibility values of pig slurry-treated silages were lower (P < 0·05) than for cow slurry-treated silages. Methane production from all animals in the experiment was comparatively low at 5·97–6·74% of gross energy intake. Metabolisable energy contents of the cow slurry-treated silages were higher than pig slurry-treated silages (P < 0·05) and the ME contents of inoculant treated silages were higher than of non-inoculated silages (P < 0·001). Thus, treatment of slurry-treated silages with bacterial inoculant enhanced fermentation quality and ME contents. The effect of slurry type on fermentation quality and feeding value was ambiguous; cow slurry-treated silages exhibiting poorer fermentation quality but higher ME contents than equivalent pig slurry-treated silages. © 1998 Society of Chemical Industry.