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Respiration experiments with high-yielding dairy cows in Northern Ireland have shown higher energy maintenance requirements than those used in the requirements standards of, e.g. France, UK, USA and Germany. Therefore, the current net energy for lactation (NEL) system of Germany was tested by comparing measured NEL intake with calculated NEL requirements based on a comprehensive dataset from feeding trials conducted at nine research institutions in Germany, Austria and Switzerland. The relationship between NEL requirements and NEL intake is described by the equation: NELrequirementsMJ/d=26.6±0.4+0.82±0.004⋅NELintakeMJ/dwithCoefficient of Determination R2=0.677,Root Mean Square Error RMSE =15.9 MJ NEL. The equation indicates a systematic over-estimation of NEL requirements in the lower performance range and an under-estimation at higher energy intake levels. A multiple regression analysis was conducted by calculating metabolisable energy (ME) requirements [MJ/d] using metabolic body size (MBS) [kg0.75], milk energy performance (LE) [MJ/d] and body weight change (BWC) [kg/d]: ​​​​​​​MEintake(MEI)[MJ]=0.651(±0.004)⋅MBS+1.37(±0.006)⋅LE+16.6(±0.31)⋅BWC withR2=0.717,RMSE=24.0 MJ. These results indicate that the energy maintenance requirements are markedly higher than presumed in the feed evaluation systems commonly in use but confirm the results from Northern Ireland (0.600-0.660 MJ ME/kg0.75 MBS). ME efficiency for lactation is also higher (kL = 1/1.37 = 0.73) than that used in the systems and is also similar to the results of Northern Ireland with 0.64-0.69. The energy contribution of BWC derived by this equation is 12.1 MJ/kg (16.6 · 0.73) and distinctly lower than that of 21-25 MJ/kg presumed by the feeding standards, e.g. in Germany. Further, maintenance requirements were linked to milk yield (energy corrected milk (ECM) [kg/d]), as is practiced in the standard Australian energy system: ​​​​​​​(MEI)[MJ]=0.640 +0.0070⋅ ECM)]⋅MBS+1.12)⋅LE +16.7⋅ BWC withR2=0.719,RMSE=24.0 MJ. These results demonstrate that maintenance energy requirements are partly dependent on milk yield. A differentiated analysis by stage of lactation showed that the regressions coefficients for MBS, LE and BWC change with lactation month; however, these findings apply especially to the first lactation months (i.e. in phases of intensive mobilisation).

To reduce losses and improve forage use efficiency in dairy farming systems, mass and nutrient flows during silage production have to be measured from the field to feed bunk. However, data on these losses at the farm scale are scarce. Thus, we examined dry‐matter (DM) losses and changes in nutrient concentrations (proximate constituents, nitrogen [N], phosphorus [P]) and energy values (net energy for lactation [NEL]) of silages on three experimental farms from ensiling to feed‐out. The investigated material included forages from permanent grassland and whole‐crop maize that were stored in 64 side‐walled bunker silos. To determine DM losses, the total‐in versus total‐out method was applied. Additionally, the changes in the nutrient concentrations were measured by comparing the concentrations before and after ensiling. Data analyses were carried out by using ANOVA, and the means across groups were compared via multiple contrast tests. On average, the farms had good silage production management. Average values showed a trend towards higher DM losses during the ensiling process with grass (9%) than maize (7%). The N and P concentrations of the silages remained mainly unchanged during the ensiling process, suggesting that the total losses of N and P were also low (

The objectives of this study were to examine the effects of varying dietary energy supply as well as the impacts of subclinical ketosis (SCK) on blood chemistry and liver health. A total 63 German-Holstein cows were housed from three weeks antepartum until sixteen weeks postpartum. After calving, cows were assigned to one of four treatment groups receiving either moderate or high energy concentrations in roughage and secondly moderate or high amounts of concentrates. Retrospectively, cows were additionally grouped according to their &beta, hydroxybutyrate concentration (SK: cows with SCK vs. CON: cows without SCK). The different energy supply of treatment groups had little effects on blood and liver variables, greater differences occurred between SK and CON cows. Liver fat content of SK cows was 34% higher compared to CON cows. Also, the activity of aspartate aminotransferase and &gamma, glutamyl transferase, bilirubin concentration, and percentage of granulocytes were increased in SK cows. The results indicate that cows were able to adjust their metabolism to different dietary energy supplies without having a clearly increased risks for metabolic disorders. However, individual animals of all groups developed a metabolic derailment during the postpartum period resulting in SCK, which is closely connected with impaired liver function, compromised immune-responsiveness, and elevated oxidative stress.

Silages have become the main feed for ruminants and biogas production and are often stored in large stacks. When a silo is filled, a plastic cover is laid out and fermentation begins. From this moment, the entire silo becomes a black box for farmers: if any spoilage due to air breaches takes place, it often will only be recognized when the stack is opened and massive losses have already occurred. In the present work, a wireless sensor monitoring system for silage stacks is designed that shall detect changes in the silage environment until feedout and can therefore enable the farmer to prevent biomass losses. The nail-shaped node design offers elevated feed safety opportunities and can be easily removed before feedout. For data transmission, LoRaWAN is used in combination with a hardware-based timer. The sensor nodes are able to endure the full extent of a silage stack storage period in a full-scale silage test of approximately 40 weeks without battery shortage. The resulting measurements show that CO2, O2, relative humidity and temperature sensors at the silage surface can detect changes within the silage environment due to air breach. Temperatures in stable regions beneath 40 cm can be detected and give information about long-term stability.

The objective of the study was to track the fate of recombinant Cry1Ab protein in a liquid manure field trial when feeding GM maize MON810 to dairy cows. A validated ELISA was applied for quantification of Cry1Ab in the agricultural chain from GM maize plants, feed, liquid manure and soil to crops grown on manured fields. Starting with 23.7 μg of Cry1Ab g(-1) dry weight GM maize material, a rapid decline of Cry1Ab levels was observed as 2.6% and 0.9% of Cry1Ab from the GM plant were detected in feed and liquid manure, respectively. Half of this residual Cry1Ab persisted during slurry storage for 25 weeks. After application to experimental fields, final degradation of Cry1Ab to below detectable levels in soil was reported. Cry1Ab exhibited a higher rate of degradation compared to total protein in the agricultural processes. Immunoblotting revealed a degradation of the 65 kDa Cry1Ab into immunoreactive fragments of lower size in all analyzed materials.

The objective of this study was to investigate the fate of transgenic cry1Ab DNA and the encoded Cry1Ab protein during the metabolic degradation of dietary feed components in dairy cows and a potential transfer to blood, milk, feces or urine. A 25-month long-term feeding trial was conducted on thirty-six Simmentaler cows allocated in two groups fed diets containing either genetically modified corn (MON810, N = 18) or the near-isogenic corn variety (N = 18). The nutrients and energy contents of both maize varieties were comparable, ensuring equivalent feed conditions. Due to infertility or other production associated diseases, nine cows per group had to be culled and were replaced by heifers. Feed samples were collected weekly, whereas samples for feces, blood and milk were collected monthly, urine samples were taken bimonthly. All samples were analyzed for cry1Ab DNA by means of end-point PCR (feces, blood, urine) and quantitative real-time PCR (feed, milk). A sensitive and highly specific ELISA, optimized to quantify immunoreactive fragments of the Cry1Ab protein, was used to determine the recombinant protein in the collected samples. Non-transgenic feed samples were free of recombinant DNA and protein within the limit of detection, while in transgenic feed samples both, a 206 bp fragment of cry1Ab and immunoreactive fragments of the Cry1Ab protein were present. In contrast, all blood, milk and urine samples were free of recombinant DNA and protein. The cry1Ab gene was not detected in any fecal sample, whereas immunoreactive fragments of the Cry1Ab protein were detected in feces from all cows fed transgenic feed. Milk of dairy cows fed genetically modified corn for 25 months should be classified not different from milk of cows fed non-transgenic corn.

A long-term study over 25 months was conducted to evaluate the effects of genetically modified corn on performance of lactating dairy cows. Thirty-six dairy cows were assigned to two feeding groups and fed with diets based on whole-crop silage, kernels and whole-crop cobs from Bt-corn (Bt-MON810) or its isogenic not genetically modified counterpart (CON) as main components. The study included two consecutive lactations. There were no differences in the chemical composition and estimated net energy content of Bt-MON810 and CON corn components and diets. CON feed samples were negative for the presence of Cry1Ab protein, while in Bt-MON810 feed samples the Cry1Ab protein was detected. Cows fed Bt-MON810 corn had a daily Cry1Ab protein intake of 6.0 mg in the first lactation and 6.1 mg in the second lactation of the trial. Dry matter intake (DMI) was 18.8 and 20.7 kg/cow per day in the first and the second lactation of the trial, with no treatment differences. Similarly, milk yield (23.8 and 29.0 kg/cow per day in the first and the second lactation of the trial) was not affected by dietary treatment. There were no consistent effects of feeding MON810 or its isogenic CON on milk composition or body condition. Thus, the present long-term study demonstrated the compositional and nutritional equivalence of Bt-MON810 and its isogenic CON.

Between 2008 and 2010 in 106 German organic dairy farms a nationwide interdisciplinary intervention study was carried out in order to develop preventive animal health management strategies for mastitis and metabolic disorders, to validate this concept and to demonstrate its feasibility. During 4 visits per farm, health indicators and influencing factors such as housing, herd management, feeding and forage production were recorded. Following a thorough assessment, farm-individual evidence-based advice was provided by the project team. About two thirds of these farm-individual intervention measures were implemented within one year and their effectiveness in terms of health improvement was monitored for one respectively two years.