F. Sutter

Emissions of ammonia, nitrous oxide and methane from different types of dairy manure during storage as affected by dietary protein content

In a storage experiment with dairy cow manure, the effects of dietary protein content and manure type on ammonia, nitrous oxide and methane volatilization as well as overall nitrogen (N) loss from manure were investigated. Early-lactating cows received rations with 175, 150 and 125 g crude protein/kg dry matter. Each ration was tested in four manure storage systems reflecting typical farm conditions. These either contained total excreta with high amounts of straw (deep litter manure) or no straw (slurry) or, proportionately, 0.9 of urine and 0.1 of faeces (urine-rich slurry) complemented by the residuals with a low amount of straw (farmyard manure). Manure samples were stored for 7 weeks under controlled conditions and trace gas emission was repeatedly measured. Reduction of N intake decreased daily N excretion and urine N proportion and, on average, led to 0.7-fold lower storage ammonia emission rates on average. Total storage N loss was simultaneously reduced with the extent depending on urine N proportion of the respective manures. A lower dietary protein content furthermore reduced nitrous oxide emission rates in most manure types but increased methane emission from urine-rich slurry; however, global warming potential (based on trace gas output) of all manures was similar with low and high dietary protein content. In deep litter manure, characterized by the highest C: N ratio, emission rates of total N, ammonia and methane were lowest, whereas nitrous oxide values were intermediate. Substantial emission of nitrous oxide occurred with farmyard manure which also had the highest methane values and, consequently, by far the highest global warming potential. C:N ratio of manure was shown to be suitable to predict total N loss from manure during storage in all manure types whereas urine N proportion and manure pH were only of use with liquid manures.

Ammonia, nitrous oxide and methane emissions from differently stored dairy manure derived from grass- and hay-based rations

Theeffects on nitrogen losses and volatilisation of ammonia, methane and nitrousoxide from manure storage were investigated using excreta of dairy cows fed twoforage-based rations, (i) young grass (ad libitum) and hay (2 kgd−1) or (ii) hay (ad libitum) and concentrate (3kg d−1). In two series either grass of low crudeprotein content (112 g kg−1 dry matter, similar tothe hay) or of high crude protein content (229 gkg−1) was used. Emissions from the resulting manureswere investigated in two common storage systems, the liquid manure system andthe slurry/farmyard manure system. Storage was performed under controlledconditions using the chamber technique to quantify trace gas emissions and themass balance method to measure total nitrogen loss. The ration characterised bythe low-protein grass resulted in higher urinary nitrogen and lower faecalnitrogen excretion than the hay ration, thus significantly enhancing totalnitrogen and ammonia emissions from all types of manure. Differences to the hayration were, however, far more pronounced feeding the high-protein grass, withthe emissions of nitrogen and ammonia accounting for the 3- to 4-fold level ofthat of the hay ration. Initial differences of the manures in nitrogen contenthad partly disappeared after storage yielding manures which differed less innitrogen fertiliser value than the fresh manures. In some but not all manuretypes there was a certain decrease in nitrous oxide emission feeding grassinstead of hay. Methane release was low with the high-protein grass of series2.Total nitrogen losses during 5 to 7 weeks of storage were lowest with farmyardmanure (11% of initial nitrogen), followed by liquid manure (19%)and slurry (30%). Calculated for the daily manure amount per cow,greenhouse gas emissions from 5 to 7 weeks stored manure were higher in theslurry/farmyard manure system than in the liquid manure system (2.4 vs 1.5kg CO2 equivalents).

Digestive and metabolic utilization of lauric, myristic and stearic acid in cows, and associated effects on milk fat quality

In an experiment with 3 × 6 Brown Swiss cows, the effects of dietary supplementations (40 g/kg) of non-esterified lauric (12 : 0), myristic (14 : 0) and stearic acid (18 : 0) on digestibility, metabolisability, milk fat composition and melting properties were investigated. The diet consisted of forage and concentrate in a ratio of 3 : 2. Cows were fed the C18 : 0 supplemented diet for 10 days before treatment feeding started for a 15-day experimental period where, at the end, excreta were quantitatively collected and gaseous exchange was measured. The DM intake averaged 17.9 kg/d for the C14 : 0 and C18 : 0 diets and was reduced (P < 0.05) by 18% in the C12 : 0 diet. The realised intakes of total C12 : 0, C14 : 0 and C18 : 0 amounted to 368, 391 and 617 g/d in the respective groups. The efficiency of ME utilization for lactation was higher (P < 0.001) in the C12 : 0 group than in the two other groups indicating differences in metabolism of C12:0 in comparison with C14 : 0 and C18 : 0. Shifts in dietary fatty acid supplementation were clearly reflected in the milk fat composition. Associated changes were elevated CLA and C18 : 1 trans when supplementing C12 : 0, and a high C18 : 1 to C16 : 0 ratio (P < 0.05) in the C12 : 0 and C18 : 0 groups which resulted in an easier melting milk fat than with supplementary C14 : 0. Despite certain favourable effects of C12 : 0 in metabolic energy utilization and milk fat melting properties (relative to C14 : 0), more research is needed on how to improve its palatability for dairy cows.

Comparative evaluation of rumen-protected fat, coconut oil and various oilseeds supplemented to fattening bulls; 1. Effects on growth, carcass and meat quality.

Growth performance, carcass and meat quality were determined in 36 fattening Brown Swiss bulls fed with maize silage‐hay‐concentrate based rations supplemented with fats and various oilseeds. The concentrate diet in the control group contained only barley and soybean meal, while the treated groups included, as partial replacement of the concentrate, rumen‐protected crystalline fat, coconut oil, whole crushed rapeseed, sunflower seed or linseed, providing additional 3% fat of total ration dry matter. Animals were housed in groups of six with one representative of each treatment in a monofactorial design and feed was offered using transponder controlled equipments. Daily gains were similar for control, protected fat, rapeseed and linseed treatments (1240 g/d on average), but were lower (P < 0.05) with sunflower seed (1135 g/d) and coconut oil (1038 g/d). Corresponding differences (P < 0.05) in carcass weights were observed. All fat supplemented groups had reduced rumen fluid protozoa counts (P < 0.05). Carcasses tended to be leaner with the fat supplements. Mostly no significant effects on other carcass quality (dressing percentage, conformation score) and meat quality traits (final pH, cooking loss, shear forces) as well as composition (dry matter, fat, collagen) occurred. Consequently, rumen protected fat and some oilseeds can be recommended to be fed to growing cattle as energy sources.

Selection, intake and excretion of nutrients by Scottish Highland suckler beef cows and calves, and Brown Swiss dairy cows in contrasting Alpine grazing systems

Nutrient intake, digestibility and live-weight changes were compared for groups of grazing cattle on two Swiss Alpine pastures in different regions (R1 and R2; both > 1500 m above sea level) during 2 years (1997 and 1998). The R1 site was an improved pasture, while R2 was an unimproved pasture of poor nutritional quality. Replicated over 2 years, R1 groups comprised four Scottish Highland suckler cows together with their calves and four Brown Swiss dairy cows (17.8 kg/day milk) kept at high stocking rates (approx. 7 cows/ha) in short rotations (intensive management system). R2 groups comprised four Highland cows with calves managed at low density (approx. 0.9 cows/ha) and set-stocked (extensive management system). Grazing seasons lasted 77 days at R1 and 127 days at R2. Intake, digestibility and faecal excretion were estimated by the slow-release alkane indicator method. Average dry matter intakes in kg/day and g/kg W 0.75 /day (in parentheses) were 17.4 (151) for dairy cows at R1 and, significantly lower, 12.7 (133) and 11.1 (111) for beef cows at R1 and R2, respectively. Herbage dry-matter intake of calves was 1.2 kg/day at both locations. Calf weight gains measured over 77 days (0.69 kg/day) were similar at the two sites and thereafter declined only slightly at R2. The N content of the herbage selected was similar in the two regions, but in other respects the herbage at R2 was of significantly poorer nutritive quality as indicated by the lower digestibility of organic matter and neutral detergent fibre at R2 compared with R1. Through feed selection, nutrient intake by beef cows was sufficient to gain weight. In contrast, dairy cows at R1 lost on average more than 50 kg of weight. Calculations were made and discussed regarding N utilization and urinary N loss, and measured faecal N and mineral excretion to allow a quantitative assessment of nutrient returns to the sward. We conclude that Highland beef cattle make poorer use of improved Alpine pasture than dairy cows though they utilize pastures of poor nutritive quality under extensive management without loss of productivity.

Effect of concentrate on nitrogen turnover and excretion of P, K, Na, Ca and Mg in lactating cows rotationally grazed at high altitude

Abstract The effects of concentrate on N and mineral excretion were determined in 2×12 early-lactating cows rotationally grazed at 2000 m above sea level for 77 days in two seasons A and B. Supplementation was oriented towards maintenance energy requirements to account for the extra requirements on alps. Two concentrates equally high in easily-fermentable energy (8.7 MJ NEL) but differing by 94 g/kg DM in absorbable protein (±maize gluten) were fed at three respective maintenance energy:protein levels as 1.0:0.8 (A/B), 0.5:0.4 (A) and 1.0:1.8 (B). A control group received no concentrate (A/B). Herbage and N intake was reduced in cows supplemented with approximately 4 kg of the low protein concentrate (1.0:0.8). Milk N excretion increased improving N utilisation by 52%. Excretion of urine N and its proportion of manure N decreased by 44 and 18% with this type of concentrate. Supplementing extra protein (1.0:1.8) reduced effects on N utilisation and excretion relative to controls, although herbage intake was similarly reduced as with the low-protein concentrate. Concentrate reduced the excretion of faecal Ca and Mg, and urine K. Seasonal N and P fertilisation rates from excreta were low. Supplementary feeding increased fertilisation rates per hectare of P and K whereas N only increased with additional protein.

Comparative evaluation of rumen-protected fat, coconut oil and various oilseeds supplemented to fattening bulls. 2. Effects on composition and oxidative stability of adipose tissues.

The effects of five different dietary fat supplements on fatty acid composition and oxidative stability of subcutaneous and kidney fat were evaluated in 36 Brown Swiss bulls and compared to a low fat diet in a monofactorial design. The following fat supplements were provided as additional fat at 30 g per kg feed dry matter: crystalline rumen‐protected fat, coconut oil, and three types of crushed whole oilseeds (rapeseed, sunflower seed and linseed). Adipose tissues reflected differences (P < 0.05) in dietary fatty acid composition although to a lower extent. Using protected fat, which contained elevated levels of trans fatty acids, and sunflower seed, containing a high proportion of linoleic acid, significantly increased C18:1 trans fatty acid proportion in the adipose tissues. The use of sunflower seed increased conjugated linoleic acid. The oilseeds resulted in lower amounts of C16:0 in favour of C18:0. Except for linseed, all fat supplemented groups improved oxidative stability of adipose tissues as compared with control. This was explained by lower proportions of unsaturated fatty acids in adipose tissue (protected fat), by elevated α‐tocopherol contents (rapeseed, sunflower seed) or by a combination of both (coconut oil). Fat colour remained unaffected by treatments. Compared to other fat supplements oilseeds, especially sunflower seed and rapeseed, can therefore be recommended to be fed to bulls in order to increase the proportions of C18 unsaturated fatty acids in adipose tissues and to maintain or improve oxidative stability.

Effect of calving period on herbage intake and nutrient turnover of Simmental and Angus suckler cows with Angus sired calves grazing subalpine and alpine pastures

Abstract Herbage intake and utilisation were measured in 12 Simmental and 12 Angus suckler cows with Angus sired calves grazing one subalpine (1000 m o.d. (ordinance datium)) and two alpine pastures (first and secondary growth; 2000 m). Calving periods were late autumn and late winter for both breeds. Herbage dry matter intake of cows and calves, determined with slow-release alkane capsules, increased from subalpine to alpine pastures from 11.9 to 15.8 and 1.1 to 3.5 kg/day, respectively. Nitrogen (N) intake was highest on regrowth pasture. Simmental cows consumed more herbage than Angus cows, even when corrected for metabolic body weight. Their calves did not differ in herbage consumption although crossbred calves had significantly higher daily gains (+16%) than Angus calves. Dam breed effects on N and phosphorous (P) excretion and N utilisation were small when corrected for differences in intake (higher in the Simmental groups). Compared to winter-calving, autumn-calving resulted in cows gaining weight but also resulted in lower daily gains of the calves despite higher herbage intake. This increased N and P losses per unit of weight gain even when calculated for cows and calves together. Accordingly, late-winter calving is advantageous for this type of alpine grazing system.

Effect of lecithins partly replacing rumen-protected fat on fatty acid digestion and composition of cow milk

The effects on fatty acid digestibility and milk fat composition of calcium soaps of palm oil fatty acids and of a 25% replacement of the Ca soaps by four different lecithins (raw, deoiled and deoiled/partially hydrolysed soy lecithin, raw canola lecithin) and soybean oil were investigated in six lactating cows each. The complete diets contained the lipid supplements at proportions of 30 g fatty acids/kg dry matter. Partial replacement of Ca soaps by soy or canola lecithins and soybean oil had small but significant effects on fatty acid digestion and utilisation, as well as the fatty acid profile in milk. Relative to Ca soaps alone, C 16:0 digestibility was slightly higher with lecithins, and percentage of conjugated linoleic acid and trans C 18:1 in milk fat increased while proportion of C 16:0 decreased. Deoiling of lecithins slightly reduced the effects on C 16:0 digestibility and excretion with milk. The influence of lecithin processing was higher than the differences between raw soy and raw canola lecithin. Nevertheless, most of the few effects observed may be related to the fatty acids supplied with the lecithins but, regarding C 18:1 trans-11 and odd chain fatty acids, there is some evidence that lecithins impair rumen microbial activity less than soybean oil.

Development of nitrogen and methane losses in the first eight weeks of lactation in Holstein cows subjected to deficiency of utilisable crude protein under restrictive feeding conditions

ABSTRACT Low-protein diets are increasingly being used in dairy cow nutrition to minimise noxious nitrogen (N) emissions. However, at parturition, the lower milk yield at that time may mask deficiency in dietary utilisable crude protein (uCP; equivalent to metabolisable protein). Under restrictive feeding conditions, farmers would limit the feed allowance to match the lower measured milk yield, thereby exacerbating the deficiency. The consequences for N emission intensity per kg milk yield and methane emissions are unknown. In this study, two diets were fed to nine Holstein cows each from parturition onwards. One diet was complete and the other was calculated as 20% deficient in uCP. Feed allowance was always oriented towards the measured milk yield. In each of the first eight lactation weeks, intake and excretion were measured for 5 d. On the last 2 d of this period, methane emission was measured in respiration chambers. The statistical model included treatment, week and interaction as effects. The real levels of uCP and energy supply across the 8 weeks were 33% and 15% below requirements, respectively, in the Deficient cows. In addition, the Deficient cows consumed 18% less dry matter (caused by substantial refusals in week 1, where energy supply was according to requirements) and produced 25% less milk (26 vs. 34 kg/d). Cows in both groups used dietary N with similar efficiency for milk protein synthesis and excreted similar proportions of the N ingested via urine and faeces. This resulted in both treatments having similar N emission intensities per kg milk N and similar urinary N as a proportion of total excreta N, suggesting a similar potential for gaseous N emissions from the manure per kg of milk. The Deficient cows emitted 22% less methane overall but had similar methane yield and emission intensity to the Controls. In conclusion, a reduction in crude protein intake immediately after parturition does not reduce N emission per unit of milk when associated with uCP deficiency.