A total of 70 Nellore bulls (18 ± 3 months of age) were used to determine the effects of crude glycerine (CG) replacing starch- v. fibre-based energy ingredients in low (LC; 0·40 concentrate) or high concentrate (HC; 0·60 concentrate) – on a dry matter (DM) basis – on DM intake (DMI), methane emissions and growth. Ten bulls were slaughtered (reference group) to obtain the carcass gain (CrG). The 60 remaining bulls (374 ± 24·5 kg) were allocated to a 2 × 3 factorial arrangement (two concentrate levels, LC or HC; and three feeding regimes, FR). The FR were: CO – without CG and maize as an ingredient of concentrate; CGM – inclusion of CG (0·10 of DM) replacing maize in the concentrate; and CGSH – inclusion of CG (0·10 of DM) replacing soybean hulls (SH) in the concentrate. Bulls fed LC or HC had similar DMI (kg/d) and growth. The DMI and average daily gain (ADG) were similar among FR. Concentrate level and FR tended to interact for methane emissions (g) per kg DMI. Bulls fed CGM had a greater G : F (g CrG/kg DMI) than those fed CO or CGSH diets. Increasing dietary concentrate (0·40–0·60) did not affect intake, methane emissions, or growth. Inclusion of CG in diets to replace SH in LC diets tended to decrease methane emissions from animals. When CG replaces SH in the diets, CrG and G:F (g CrG/kg DMI) are decreased compared with bulls fed CGM.

Increasing phosphorus (P) fertilizer use efficiency in grassland is desirable, since uncertainty exists over the reserves of finite phosphate rock and its future availability. This necessitates revaluation of the current P fertilizer recommendations for grassland to examine the potential to increase fertilizer P efficiency. The present paper reports results from a long-term grassland P experiment (17 years) on two sites in which annual P fertilizer application rates were 0, 15, 30 and 45 kg P/ha/year. The effect of P fertilizer rate on herbage production and mineral concentration in herbage were investigated in addition to the soil test P (Morgan's) trends and P balance over the duration of the experiment for each rate of P fertilizer. The results showed that the P response to herbage yield and P concentration was similar on both sites. The response of herbage yield to P fertilizer was limited to harvests early in the growing season. The P concentration in herbage was lower in mid-season than in spring or autumn. Annual P fertilizer applications > 30 kg P/ha/year were required to maintain soil P levels at their initial levels over the duration of the experiment.

The present study investigated the effects of different levels of urea nitrogen (N) fertilizer on nutrient accumulation, in vitro rumen gas production and fermentation characteristics of forage oat straw (FOS) from oats (Avena sativa L. ‘Qinghai 444’) grown in the Tibet region of China. Fertilizer, applied at seeding (day 1), stem elongation (days 52–54) and heading (days 63–67), increased plant height and prolonged the maturity stage of the plant by 4–11 days compared with the non-fertilized control. Oat plants were harvested at maturity at the node 3–4 cm above ground, and then separated into grains and FOS. Both FOS and grain yields increased quadratically with increasing N fertilization, and their theoretical maximums occurred at the N fertilizing rates of 439 and 385 kg/ha, respectively. Increases in N fertilization did not affect the hemicellulose content of FOS, but substantially promoted the accumulation of crude protein, cellulose and lignin, resulting in a decrease in the energy content available for metabolism. A 72-h incubation of FOS with rumen fluids from lactating cows showed that increasing N resulted in FOS that showed a slower fermentation rate, decreased in vitro dry matter disappearance and lower cumulative gas production, but unchanged fermentation gas composition. Nitrogen fertilization increased the final pH in culture fluids and decreased the microbial volatile fatty acid (VFA) production. The molar proportions of acetate and propionate were not affected, but molar propionate proportion decreased linearly with increasing urea fertilization, and consequently, the ratio of lipogenic (e.g., acetate and butyrate)-to-glucogenic acids (propionate) tended to increase. In brief, increasing urea N fertilization promoted the growth of forage oats and increased the biomass yield as well as the crude protein and cellulose content of FOS. Considering the negative effect of increased lignin content on nutrient digestibility and total VFA production, the suggested range of urea N fertilization is 156–363 kg N/ha for forage oats planted in Tibet to retain the nutritive value of FOS in the rumen.

An experiment was performed to determine the effect of triterpenoid saponins from powdered root of Saponaria officinalis L. (SO) on some blood metabolic parameters and hormone concentrations in dairy cows. Three dairy Polish Holstein-Friesian cows were used in the experiment in a 3 × 3 Latin Square arrangement. Animals were fed twice a day with a control diet and two experimental diets – a diet supplemented with either 440 or 660 g/d of the powdered S. officinalis root (SO1 and SO2, respectively). Each of the three experimental cycles lasted for 26 days, including a 23-day adaptation period and a 3-day sample collection period. Blood samples were collected from the jugular vein from 24th to 26th day of the experiment. Total high-density lipoproteins cholesterol (HDL) and low-density lipoproteins cholesterol (LDL), as well as triglycerides, free fatty acids (FFA) and glucose, were assayed in serum. Fatty acid composition in the blood was also analysed. Moreover, concentrations of insulin, glucagon, leptin, triiodothyronine (T3) and thyroxine (T4) were measured. It was demonstrated that total and HDL-cholesterol concentrations were significantly elevated in the blood of cows treated with experimental diets; however, LDL-cholesterol remained unchanged. No concentrations of triglycerides, FFA or glucose were influenced by saponins. Two fatty acids (C16 : 0 and C16 : 1c9) were markedly reduced when SO was used, while C18 : 1t11 decreased with increasing levels of SO. The significant increase of C20 : 4n-6 in animals treated with SO was observed. Both saponin diets resulted in a slight increase in insulin concentration and the SO2 diet evoked an emphatic rise of glucagon concentration. The concentration of T3 also increased after consumption of the experimental diet. The current study shows for the first time that triterpenoid saponins from S. officinalis can alter blood parameters in ruminants. These effects seem to result from saponin-induced changes in the rumen.

The control of Campylobacter in poultry is considered a public health priority and some intervention strategies have been implemented in Denmark. Nonetheless, Campylobacter infection in poultry can still be considerable particularly during the summer when the most promising Campylobacter control strategy seems to be the use of fly screens. The use of cost-effective vaccines against Campylobacter is also desirable. In order to control Campylobacter, poultry producers need to make crucial decisions under conditions of uncertainty. With the aim of assisting poultry producers in decision making regarding Campylobacter control strategies, the objective of the present study was to produce a decision support system that integrated knowledge and used a Bayesian approach to handle uncertainty. This decision support system integrated epidemiological data, microbiological considerations, financial information and potential control strategies (the use of fly screens and hypothetical vaccines). In conclusion, results from model and sensitivity analyses indicated that the financial variables (cost–benefit functions) and the effectiveness of the different control strategies drove the results.

The incursion of Bluetongue disease into the UK and elsewhere in Northern Europe in 2008 raised concerns about maintaining an appropriate level of preparedness for the encroachment of exotic diseases as circumstances and risks change. Consequently the Scottish government commissioned the present study to inform policy on the specific threat of Bluetongue virus 8 (BTV8) incursion into Scotland. An interdisciplinary expert panel, including BTV and midge experts, agreed a range of feasible BTV incursion scenarios, patterns of disease spread and specific control strategies. The study was primarily desk-based, applying quantitative methodologies with existing models, where possible, and utilizing data already held by different members of the project team. The most likely distribution of the disease was explored given Scotland's agricultural systems, unique landscape and climate. Epidemiological and economic models are integrated in an ex-ante cost-benefit appraisal of successful prevention of hypothetical BTV8 incursion into Scotland under various feasible incursion scenarios identified by the interdisciplinary panel. The costs of current public and private surveillance efforts are compared to the benefits of the avoided losses of potential disease outbreaks. These avoided losses included the direct costs of alternative vaccination, protection zone (PZ) strategies and their influence on other costs arising from an outbreak as predicted by the epidemiological model. Benefit-cost ratios were ranked within each incursion scenario to evaluate alternative strategies. In all incursion scenarios, the ranking indicated that a strategy, including 100% vaccination within a PZ set at Scottish counties along the England–Scotland border yielded the least benefit in terms of the extent of avoided outbreak losses (per unit cost). The economically optimal vaccination strategy was the scenario that employed 50% vaccination and all Scotland as a PZ. The results provide an indicator of how resources can best be targeted for an efficient ex-ante control strategy.

The type and processing of cereals for beef cattle are key factors to maximize performance without increasing the risk of ruminal acidosis. The current work studied the effect of grinding (G) or dry-rolling (R) the cereals in a concentrate based on maize (M) or barley (B) on the rumen environment of eight 6-month-old Holstein calves, which received either M or B for 70 days, offered as G and R in two consecutive periods. Daily feed intake pattern, rumen fermentation traits, total rumen bacteria and relative proportions of Streptococcus bovis and Selenomonas ruminantium were characterized twice in each period at 0, 4 and 8 h after feeding. Dry-rolling promoted a 0·25 reduction of concentrate intake during the first 4 h after feeding. Neither cereal type nor its processing form promoted differences in ruminal fermentation at 0 and 4 h; however, 8 h after feeding R cereals resulted in higher rumen pH (6·17 v. 5·71) and lower concentration of lactic acid (88·1 v. 156 mg/l) and volatile fatty acids (only in diet B, 118 v. 164 mm/l) compared with G. Little effect of dietary factors in the target rumen microorganisms were observed. The more balanced fermentation observed with R cereals may be explained by the lower concentrate intake promoted during the first 4 h, coupled with a more difficult access of bacterial enzymes to their starch, thus reducing its fermentation rate. Therefore, feeding dry-rolled cereals may be useful to reduce the risk of acidosis by regulating the intake pattern of the concentrate and/or its fermentation rate.

Most acid sulphate soils (ASSs) in the Pearl River Delta of South China have been traditionally reclaimed for rice cultivation, but the rice yield in most of these paddy fields is lower than the average rice yield in China due to extremely high soil acidity. In the present study, a range of sulphate and acidity parameters were investigated in ASS profiles in three types of paddy fields in Taishan City (Guangdong Province, China) divided based on the local rice productivity (4500, 3000 and 1500 kg/ha) using an abandoned ASS (uncultivated) as the control treatment to ascertain key yield constraining parameters. Soluble acidity (SA), exchangeable acidity (ExA), soluble sulphate (SS) and net acid-soluble sulphate (NAS) increased with increasing soil depths from 0 to 100 cm and then decreased abruptly with further increases in the depth. However, the depth distribution of exchangeable sulphate (ES) was uniform. The soil acidity and sulphate contents differed significantly in three sampled paddy fields. The values of SA and SS in the soils at depths of 0–100 cm in the studied ASS were lower compared with those in the uncultivated ASS and the ExA in soils at depths of 0–40 cm in ASS were lower compared with those observed in the uncultivated ASS. A correlation analysis revealed that SA was strongly correlated with SS and ExA with NAS. Soluble acidity, ExA, SS and NAS in the ASS were significantly associated with rice yield. Exchangeable acidity in the plough layer (0–20 cm) of soils was the most sensitive indicator of soil quality affecting rice yield among those in soils from 0 to 140 cm depth. It is interesting to note that SA, SS and NAS were more sensitive indicators of soil quality affecting rice yield at 60–100 cm than at 0–40 cm depth. Principal component analysis showed that pH value, ExA and ES in soils at depths of 0–40 cm and SA, SS and NAS in soils at depths of 60–100 cm constituted the critical soil acidity and sulphate characteristics that were strongly correlated with rice yields. This finding implies that controlling the ExA in the plough layer and the SA and NAS in the Jarosite layer should be the major focus of studies aimed at the amelioration of ASSs.

In horses, the quantity of faeces and the faecal concentrations of plant and synthetic alkanes are inconsistent throughout the day. The estimation of feed intake and digestibility can additionally be limited by irregular and incomplete faecal recovery of alkanes that are used as dietary markers. The correction of alkane concentrations minimizes the bias of estimates, but requires the determination of faeces quantity by total collection. However, in consideration of the dynamics of alkane concentrations in faeces, sampling at selected timeframes throughout a day may be useful in avoiding such correction. Five adult horses were fed a hay-based diet offered three times a day in equal amounts. Horses received a bolus with similar quantities of n-octacosane (C28), n-dotriacontane (C32) and n-hexatriacontane (C36) synthetic alkanes twice a day. Total faeces were quantified over 3 consecutive days. Dry matter intake (DMI), output (DMO) and digestibility (DMD) were determined from the total collection trial and additionally estimated for each of 12 equal timeframes throughout the day. The diurnal patterns of the single faeces quantity (SFQ) and faecal alkane concentrations were similar between horses and were repeated from day to day. The intra-day dynamic of SFQ was pronounced. The dynamic of the faecal concentration was much more pronounced when the alkane was administered twice instead of three times a day. The faecal recovery of alkanes that has been calculated from the total collection trial ranged from 82 ± 4·1% for C36 to 108 ± 11·1% for C28. Measured DMI was 12·0 kg/day, measured DMO was 5·9 kg/day and measured DMD was 0·51. Reliable estimates were obtained for DMI with 12·3 ± 0·79 kg/day for the combination of n-nonacosane (C29) and C28 and 12·1 ± 1·01 kg/day for the combination of n-tritriacontane (C33) and C28 at 2 h after administration, and 12·1 ± 0·96 kg/day for the combination of n-hentriacontane (C31) and C32 at 2 h prior to the morning meal, which included the first bolus administration. When calculated from DMO and DMD, DMI was 12·2 ± 0·89 kg/day for C29 and 12 ± 1·0 kg/day for C33 between 5 and 6 h after the morning meal. Estimates of DMD were unbiased between the 3rd and 4th hour after the morning meal with 0·52 ± 0·014 for C29 and 0·51 ± 0·021 for C33, respectively. The DMO was 5·7 ± 0·34 kg/day and 6·1 ± 0·43 kg/day when estimated 3–4 h after the 2nd meal, or prior to the 2nd bolus administration, using the product of SFQ and the daily defecation frequency or the synthetic alkanes, respectively. Knowledge of defecation dynamics might be helpful for simplifying experimental trials. They specifically followed intake dynamics, which can prospectively be used to select sampling timeframes. Based upon current results, a selection of two to three spot samples of faeces that are evenly distributed between 2 h before and 6 h after the morning meal, which was the time of bolus administration, allows for the greatest reliability. Defecation dynamics are probably less influenced by ration/bolus type, rate of exercise, or gut peristalsis, which nevertheless can result in individual shifts of optimal timeframes.

The mixing of pigs unacquainted with each other in commercial pig production is a standard procedure which leads to agonistic interactions with a wide range of individual pig behaviour. Hence, the aims of the present study were to assess the heritabilities of agonistic behaviour and to estimate correlations between three different age groups (weaned pigs n = 1111, growing pigs n = 446 and breeding gilts n = 279). The behavioural observation analysis included a period of 17 h directly after mixing as weaned pigs, growing pigs and breeding gilts (220 days of age) whereby the following agonistic traits were observed: number of fights (NF), duration of fights (DF), initiated fights (IF), received fights (RF), fights won (FW) and fights lost (FL). The behaviour of the weaned and growing pigs was significantly influenced by cross-fostering, their weight at mixing and litter attributes. Cross-fostered animals showed fewer agonistic interactions as weaned pigs and as growing pigs than non-cross-fostered animals. The influence of weight revealed that heavier pigs had a higher NF score at weaning and as growing pigs. The random litter effect explained up to 0·08 of the total variance in weaned and 0·04 in growing pigs, whereby this could partly be explained by litter size. Pigs from larger litters tended to have more agonistic interactions. The heritabilities of the recorded traits were at a low to medium level but similar between the age groups. There were high correlations between NF and all other traits in weaned pigs. The trait IF showed that the more fights a pig initiated, the more it won. This was also found for growing pigs and breeding gilts. The relationships between the age groups provided no uniform trend. The phenotypic correlations were low and the genetic correlations varied widely, partly due to the small sample size.

Thirty-two lambs (n = 8 per treatment) were fed a total mixed ration (TMR) formulated either with palm oil (CTRL; 34 g palm oil/kg TMR) or flaxseed (FS) (85 g FS/kg TMR) alone or enriched with quercetin (QCT, 34 g palm oil plus 2 g QCT/kg TMR; FS-QCT, 85 g FS plus 2 g QCT/kg TMR). The animals were slaughtered after being fed for at least 5 weeks with the experimental diets and samples of ruminal contents and ruminal liquid were collected for quantitative real-time polymerase chain reaction analyses of ruminal microbial species and fatty acid profile or in vitro fermentation, respectively. Results demonstrated that Butyrivibrio vaccenic acid (VA) and Butyrivibrio stearic acid (SA) producing bacteria copy numbers were decreased when FS was added to the diet of fattening lambs, which seemed to be in agreement with numerically (but not significantly) lower values for gas production, methane production and butyric acid during in vitro incubation. Ciliate protozoa were significantly enhanced by QCT, which was in accordance with numerically (but not significantly) higher values for in vitro methane production. Moreover, the modifications observed in ruminal microbial populations (Butyrivibrio and ciliate protozoa) when FS and QCT were included together (but not separately) in the diet of fattening lambs were probably related to a trend towards significantly higher values of rumenic acid (RA) in ruminal content. In conclusion, when FS and QCT were administered together in the diet of fattening lambs quantitative changes in the ruminal microbiota were observed, which might have promoted an increment of RA concentration in ruminal contents.

The objective of the current study was to quantify the response of pasture to phosphorus (P) fertilizer application and legume introduction, by measuring herbage yield, nitrogen (N) and P content, and weight gain of calves in native pastures of Uruguay. Quantitative relationships between pasture characteristics and post-weaning daily live weight gain (DLWG) were also examined. The treatments studied were native grassland (NG) and improved pasture, oversown with Lotus corniculatus L. and Trifolium repens L. with annual applications of either 13 and 26 kg P/ha. From 1996 to 2001 the treatments were evaluated each year with a new group of calves. Total herbage yields of the oversown pastures were not always higher than NG in the initial years, but legume production increased, although without significant differences between P rates on legume or total yield. This was also reflected in the N and P status of the swards. In the last 2 years legume proportion had declined to <0·1, but total herbage yield was significantly higher in the improved pastures. The average DLWG over the 6 years of measurements were 0·319, 0·478 and 0·586 kg/day for NG, P1 and P2, respectively, with average total live weight gain increased 1·8- and 2·5-fold by the legume introduction and annual addition of 13 and 26 kg P/ha, respectively. The study demonstrated that the evaluation of pasture response to P application should not be limited to assessing forage yield increase. Phosphorus availability in the herbage was a better predictor of animal performance than pasture yield. The study highlights that the benefits of oversowing and fertilizer inputs are short-lived, as withholding of fertilizer in the last 2 years resulted in a loss of sown legumes and decline in animal production.

Barley (Hordeum vulgare L.) is one of the most important cereal crops in the world and powdery mildew caused by the airborne fungus Blumeria graminis f. sp. hordei is a worldwide disease that causes frequent epidemics in Central and Northwestern Europe. Psaknon was one of first varieties in which powdery mildew resistance (Mlp1) was found, but no commercial variety with this resistance and no pathotype with the corresponding virulence have been recorded. In 2014, four isolates collected in the Czech Republic and virulent to Mlp1 were tested on 25 varieties and were also virulent to seven other resistances, including Venezia. These isolates revealed the presence of Mlp1 in six commercial spring and winter barley varieties from Southeastern and Central Europe and in six German winter barley candidate lines for registration in Czech variety trials. Based on the combined results of virulence and resistance, it was concluded that Vp1 is becoming a major factor contributing to increased virulence complexity and pathotype diversity in Central Europe. In breeding, employment of the non-specific resistance Mlo for spring barley and accumulation of quantitative resistance genes for winter barley can still be recommended in addition to exploiting a non-host resistance from an alternative source such as that present in Hordeum bulbosum.

An in vitro study was conducted to investigate the effects of condensed tannin (CT) structural properties, i.e. average polymer size (or mean degree of polymerization), percentage of cis flavan-3-ols and percentage of prodelphinidins in CT extracts on methane (CH4) production and fermentation characteristics. Condensed tannins were extracted from eight plants in order to obtain different CT types: blackcurrant leaves, goat willow leaves, goat willow twigs, pine bark, redcurrant leaves, sainfoin plants, weeping willow catkins and white clover flowers. They were analysed for CT content and CT composition by thiolytic degradation, followed by high performance liquid chromatography (HPLC) analysis. Grass silage was used as a control substrate. Condensed tannins were added to the substrate at a concentration of 40 g/kg, with or without polyethylene glycol (+ or −PEG 6000 treatment) to inactivate tannins, then incubated for 72 h in mixed buffered rumen fluid from three different lactating dairy cows per run. Total cumulative gas production (GP) was measured by an automated GP system. During the incubation, 12 gas samples (10 µl) were collected from each bottle headspace at 0, 2, 4, 6, 8, 12, 24, 30, 36, 48, 56 and 72 h of incubation and analysed for CH4. A modified Michaelis-Menten model was fitted to the CH4 concentration patterns and model estimates were used to calculate total cumulative CH4 production (GPCH4). Total cumulative GP and GPCH4 curves were fitted using biphasic and monophasic modified Michaelis-Menten models, respectively. Addition of PEG increased GP, GPCH4, and CH4 concentration compared with the −PEG treatment. All CT types reduced GPCH4 and CH4 concentration. All CT increased the half time of GP and GPCH4. Moreover, all CT decreased the maximum rate of fermentation for GPCH4 and rate of substrate degradation. The correlation between CT structure and GPCH4 and fermentation characteristics showed that the proportion of prodelphinidins within CT had the largest effect on fermentation characteristics, followed by average polymer size and percentage of cis flavan-3-ols.

Modifying the extent of fatty acid (FA) biohydrogenation (BH) in the rumen through diet formulation is an effective strategy for changing the content of unsaturated FAs (USFAs) in meat. The present study investigated the effects of different sources of forage in high-concentrate diets on intake, digestibility, rumen fermentation, ruminal BH, duodenal flow of FAs and rumen microbiota in Nellore steers. Intake of neutral detergent fibre (NDF) was higher in animals fed with maize silage (MS) than in those fed with sugar cane (SC) and sugar cane bagasse (SB). Higher digestibility of dry matter and NDF was found in animals fed with MS than in those fed with the other diets. In addition, higher crude protein digestibility was observed in animals fed with sugar cane bagasse than in those fed with SC. Non-fibre carbohydrate (NFC) digestibility was higher in animals fed with sugar cane than in those fed with the other diets. Intake of total and individual FAs such as C18 : 1 cis-9, C18 : 2, and C18 : 3 was similar between animals fed with MS and SB, but decreased in animals fed with SC. Diets containing MS and SB showed higher total digestibility of saturated FAs (SFAs) and USFAs, respectively and total FAs and ruminal BH of C18 : 1 and USFA. Intestinal digestibility of overall FAs did not differ among treatments, except for C18 : 3, which increased in animals fed with SC and SB. The profile of FAs in duodenal digesta and faecal outputs did not differ among treatments. However, the flow of NDF was higher in animals fed with SC than in those fed with MS and SB. Animals fed with SB showed higher values of pH than those fed with MS and SC. Animals fed with SC showed lower values of ammonia-nitrogen. Protozoan counts were only influenced by diet for species that belonged to the genera Dasytricha and Isotricha. Populations of fibrolytic bacteria (Ruminococus flavefaciens, Ruminococus albus and Fibrobacter succinogenes) were similar among diets. Populations of Selenomonas ruminantium increased 2·5 and 5 times in animals fed with MS when compared with those fed with SC and SB, respectively. The use of MS increased intake and digestibility of NDF, and the use of SC decreased ruminal BH of total USFA without changing the flow of FAs to the duodenum. Thus, different sources of forage in high-concentrate diets do not modify the duodenal flow of USFA or fibrolytic bacteria. This must be taken into account when formulating diets to modulate ruminal upsets without altering intake.

The objectives of the current study were to compare and model feed intake responses to ambient temperature across species and to assess opportunities to use cross-species (CS) data to parameterize models when species-specific (SS) data were limited. Literature searches were conducted to identify studies reporting intake during thermal stress compared with thermoneutral (TN) conditions. The resulting data set comprised 614 treatment means from 108 studies on livestock responses to thermal stress. An analysis of variance was conducted with the CS data set to identify the effects of species, temperature and species by temperature interactions on intake as (fractional feed intake; FFI). Four models were derived from the CS data set and root mean squared prediction error (RMSPE) and concordance correlation coefficients (CCC) of these models were compared with models of the same form derived from SS data sets. Models used explanatory variables for (1) duration of exposure; (2) mean temperature; (3) minimum and maximum temperatures; or (4) difference between minimum and maximum temperatures. An additional model accounting for temperature and stage of production was derived from the SS data. Analysis of variance demonstrated that the species by temperature interaction did not have a significant effect on FFI. Across species, intake decreased with temperature. Notably, all species demonstrated a constant decrease in intake across the TN zone indicating the previous assumption of constant intake during thermoneutrality may be not fully valid. When compared on a SS basis, SS-derived models had marginally lower RMSPE and higher CCC when compared with models derived from the CS data sets. The model fit with production data had the lowest RMSPE and highest CCC within the study. When compared over temperature ranges with minimal data available in some species (e.g., cold stress), using CS models often resulted in decreased RMSPE and improved CCC when compared with SS models. Although fitting models based on SS data allows for incorporating unique covariates, like level of production, fitting responses based on CS data can help to improve model estimates when knowledge gaps exist.

A completely randomized experiment for planting highland barley in 36 field plots of the Lhasa Agricultural Experiment Station was applied to investigate the effect of urea nitrogen (N) fertilization levels of 0 (control), 156, 258, 363, 465 and 570 kg/ha on nutrient accumulation, in vitro rumen gas production and fermentation characteristics of highland barley straw (HBS). Each urea application was divided into three portions of 0.4, 0.3 and 0.3 and sequentially fertilized at seeding (growth stage (GS) 0), stem elongation (GS 32) and heading (GS 49), respectively. The maturity stage lasted 5–13 days longer in response to the urea N fertilization compared with the control. After removing grains, HBS biomass was harvested at maturity. The biomass yields of leaf, stem, straw and grain were increased quadratically with increasing urea N fertilization, and HBS and grain yields peaked at the estimated urea N fertilization levels of 385 and 428 kg/ha, respectively. The increase of urea N fertilization increased the accumulation of crude protein, cellulose and lignin, and decreased the content of ash and hemicellulose in HBS, resulting in a decrease of the energy content available to be metabolized. After incubating HBS for 72 h with rumen fluids from lactating cows, the urea N fertilization decreased in vitro dry matter disappearance and cumulative gas production, and slightly altered fermentation end-gas composition. Urea N fertilization decreased microbial volatile fatty acid production, but did not alter the ratio of lipogenic acetate and butyrate to glucogenic propionate. In a brief, the current urea N fertilization strategy promoted the growth of the highland barley and increased biomass yield, protein and cellulose accumulation of HBS. A urea N fertilization level ⩽385 kg/ha could be sufficient for growth of highland barley in Tibet without a consequent nutritive reduction in ruminal digestion.

Three different explanatory indicators for reduced light use efficiency (LUE) under limited nitrogen (N) supply were evaluated. The indicators can be used to adapt dry matter production of crop simulators to N-limited growth conditions. The first indicator, nitrogen factor (NFAC), originates from the CERES-Wheat model and calculates the critical N concentration of the shoot as a function of phenological development. The second indicator, N nutrition index (NNI), calculates a critical N concentration as a function of shoot dry matter. The third indicator, specific leaf nitrogen (SLN) index (SLNI), has been newly developed. It compares the actual SLN with the maximum SLN (SLNmax). The latter is calculated as a function of the green area index (GAI). The comparison was based on growth curves and fitted to empirical data, and was carried out independently from a dynamic crop model. The data set included four growing seasons (2004–2006, 2012) in Northern Germany and seven modern bread wheat cultivars with varying N fertilization levels (0–320 kg N/ha). The influence of N shortage on LUE was evaluated from the beginning of stem elongation until flowering. With the exception of 2005, the highest productivity was observed for the highest N level. A moderate N shortage primarily reduced GAI and therefore light interception, while LUE remained stable under moderate N shortage. The relative LUE (rLUE) of a specific day was defined as the ratio of actual to maximal LUE. None of the indicators was proportional to rLUE, but the relationships were described well by quadratic plateau curves. The correlation between simulated and measured rLUE was significant for all explanatory indicators, but different in terms of mean absolute error and coefficient of determination (R2). The performance of SLNI and NNI was similar, but the goodness of prediction was much lower for NFAC. Compared with NNI and NFAC, SLNI corresponded to leaf N and was therefore sensitive to N translocation from leaves to growing grains during the reproductive stage. For this reason, SLNI may have the potential to improve simulation of dry matter production in wheat crop simulators.

The current study was aimed at exploring the relationship between egg physical parameters that can be evaluated before incubation without egg breakage and hatchability of chick embryos. Eggs from laying hens of the White Leghorn (WL), Rhode Island White (RIW) and Rhode Island Red (RIR) lines were examined using a ranking system for analysing influence of egg parameters on hatchability. Specifically, eggs were subdivided into three groups whose non-destructive measurement values were: (i) within the mean ± standard deviation (σ), (ii) < mean minus σ and (iii) > mean plus σ. As a result, the smaller WL and RIW eggs, where values of weight, volume, surface area, length and maximum breadth were < mean minus σ, appeared to be more successful at hatching than the bigger ones. Hatchability of the more ‘round-shaped’ WL and RIW eggs, whose shape index was 0·76−0·80, tended to be higher. Effect of egg-specific gravity on hatchability varied in different layer strains, and genetic background seemed to be an essential factor determining relationship between hatchability and other egg characteristics. The RIW eggs of larger weight with a relatively small surface area appeared to have decreased hatchability, supposedly due to insufficient gas exchange of embryos.

The current study evaluated the nutritional impact of crude glycerine (CG) supplementation to wethers fed only forage grass. Eight Polwarth wethers were used in a replicated 4 × 4 Latin Square. Treatments consisted of no CG (control, CON) or intra-ruminal infusion of CG at daily rates of 0·5, 1·5 or 3·0 ml/kg body weight (BW). In each Latin Square, four animals were fed Avena strigosa and four were fed Cynodon sp. hay ad libitum. The actual concentration of glycerol in diet was similar for both forage types and varied from 21 to 364 g/kg dry matter. No interactions between forage type and CG treatments were detected and no differences were observed between the CON and 0·5 CG treatment for most variables. Both the organic matter (OM) and the digestible OM intake decreased linearly at increased levels of CG infusion, whereas no treatment effect was observed on OM and neutral detergent fibre (NDF) digestibility. The duodenal flow of rumen microbial nitrogen (N) was not affected, whereas the duodenal flow of α-amino N decreased linearly at increased levels of CG infusion. In conclusion, CG supplementation at a rate of up to 0·5 ml/kg BW/day did not change the nutrient supply whereas greater amounts of CG supplementation negatively impacted the nutrient supply to wethers fed only grass forage. The forage digestibility, in turn, was not affected by CG supplementation.