Simplified cultivation technologies for rice have become increasingly attractive in recent years in China because of their social, economical and environmental benefits. To date, several simplified cultivation technologies, such as conventional tillage and seedling throwing (CTST), conventional tillage and direct seeding (CTDS), no-tillage and seedling throwing (NTST), no-tillage and direct seeding (NTDS) and no-tillage and transplanting (NTTP), have been developed in China. Most studies have shown that rice grown under each of these simplified cultivation technologies can produce a grain yield equal to or higher than traditional cultivation (conventional tillage and transplanting). Studies that have described the influences of agronomic practices on yield formation of rice under simplified cultivation have demonstrated that optimizing agronomy practices would increase the efficiencies of simplified cultivation systems. Further research is needed to optimize the management strategies for CTST, CTDS and NTST rice which have developed quickly in recent years, to strengthen basic research for those simplified cultivation technologies that are rarely used at present (such as NTTP and NTDS), to select and breed cultivars suitable for simplified cultivation and to compare the practicability and effectiveness of different simplified cultivation technologies in different rice production regions.

Plant-specific transcription factors belonging to the dehydration response element binding (DREB)/C-repeat binding factor (CBF) subfamily of the AP2/EREBP family specifically interact with dehydration-responsive elements (DRE)/C-repeat (CRT) and control the expression of many stress-inducible genes in plants. Two major subgroups of DREB proteins are represented by DREB1 and DREB2, which are induced specifically under cold and drought/salt stress, respectively. A DREB2 transcription factor gene from sorghum, SbDREB2 was identified and cloned in binary vectors, such that it was driven either by a constitutive CaMV35S promoter or a stress-inducible rd29A promoter. These gene constructs were transferred into rice through Agrobacterium tumefaciens-mediated transformation. Expression patterns of the native DREB gene (OsDREB2) and the transgene (SbDREB2) were similar. Both genes showed induction at 1 h exposure to drought, after which expression gradually dropped to basal levels by 24 h. Constitutive expression of SbDREB2 led to pleiotropic effects in rice and these transgenics did not set seed. The rd29A: SbDREB2 rice plants set seed and the grains collected from primary transformants were sown to raise T1 plants. The drought-stressed rd29A: SbDREB2 transgenics showed a significantly higher number of panicles as compared to the wild-type rice plants. Other phenological and agronomic traits were not affected in wild-type and rd29A: SbDREB2 transgenic rice.

Water requirements, total body water (TBW) and water distribution were evaluated in Awassi sheep and Aardi goats of Saudi Arabia. Ten non-pregnant and non-lactating females from each species were individually housed in shaded pens during winter and summer seasons. Each experimental period lasted for 2 weeks; the first week was an adaptation period, followed by an evaluation period of 1 week. Feed and water intake together with body weight were recorded daily. Five animals from each group were used for determination of body water, extracellular fluid (ECF) and plasma volume (PV) using dilution techniques. Urea and sodium thiocyanate were used for the estimation of body water and ECF, respectively, and Evans blue for PV determination. Intracellular fluid (ICF) and blood volume (BV) were calculated. Feed intake was not affected by either season or species. During the winter season, Aardi goats had lower water intake in comparison with Awassi sheep, but water intake increased in all animals during summer. TBW increased during summer in all animals, but with higher values in the Aardi goats. During summer, ECF tended to increase in Aardi goats. PV, expressed as a proportion of body weight, was not affected by season, but it was maintained at higher levels in the Aardi goats irrespective of season. It could be concluded that Aardi goats used water more economically when the ambient temperature was lower but, during the summer when ambient temperatures were higher, they increased their water intake and BW content to a greater extent and stored more water in the ECF compartment compared to Awassi sheep.

In the current Dutch protein evaluation system (the DVE/OEB1991 system), two characteristics are calculated for each feed: true protein digested in the intestine (DVE) and the rumen degradable protein balance (OEB). Of these, DVE represents the protein value of a feed, while OEB is the difference between the potential microbial protein synthesis (MPS) on the basis of available rumen degradable protein and that on the basis of available rumen degradable energy. DVE can be separated into three components: (i) feed crude protein undegraded in the rumen but digested in the small intestine, (ii) microbial true protein synthesized in the rumen and digested in the small intestine, and (iii) endogenous protein lost in the digestive processes.

Based on new research findings, the DVE/OEB1991 system has recently been updated to the DVE/OEB2010 system. More detail and differentiation is included concerning the representation of chemical components in feed, the rumen degradation characteristics of these components, the efficiency of MPS and the fractional passage rates. For each chemical component, the soluble, washout, potentially degradable and truly non-degradable fractions are defined with separate fractional degradation rates. Similarly, fractional passage rates for each of these fractions were identified and partly expressed as a function of fractional degradation rate. Efficiency of MPS is related to the various fractions of the chemical components and their associated fractional passage rates. Only minor changes were made with respect to the amount of DVE required for maintenance and production purposes of the animal. Differences from other current protein evaluation systems, viz. the Cornell Net Carbohydrate and Protein system and the Feed into Milk system, are discussed.

Cotton is the dominant crop in the northern Xinjiang oasis of China; it accounts for 0·78 of the total planting area and represents a major contribution to economic development. The objective of the present study is to determine how cotton plantation age affected chemical and microbiological properties of the soil. The time substitution method was used on plantation farmlands, reclaimed from uncultivated land 0, 5, 10, 15 and 20 years ago. A total of 250 soil samples, at depths of 0–200, 200–400, 400–600, 600–800 and 800–1000 mm, were collected from cotton fields in 10 farms of each age category. There were significant differences in soil organic carbon (SOC), total soil nitrogen (TSN), soil available nitrogen (SAN), soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN). There were also differences in the activities of cellulase, invertase and urease between soil layers and plantation ages, and these were most evident in the 200–400 mm layer. The cumulative rates of SOC and SMBC in the 0–1000 mm soil layer at the 5-, 10-, 15- and 20-year sites were 0·89, 0·99, 1·01 and 0·92 mg/kg/yr and 16, 16, 16 and 15 mg/kg/yr, respectively, compared to that at the control site (0 year). The cumulative amounts of SOC and SMBC increased gradually and then decreased, reaching a maximum at plantation ages of 13·1 years and 11·1 years, respectively. This suggests that incorporation of post-harvest cotton residues could be used as an effective measure to improve SOC in farmland of Xinjiang Oasis, and may be recommended for adoption in cotton growing in semi-arid oasis agriculture.

Pests and diseases impact on crop yield and quality, and also reduce resource-use efficiency. Improved crop protection strategies to prevent such damage and loss can increase production and make a substantial contribution to food security. DNA-based technologies are likely to greatly increase the speed, sensitivity and accuracy of pest and pathogen detection and diagnosis. Rapid sequencing of nucleic acids from infected plants will aid identification of novel disease agents. Biomarkers of disease or crop damage such as volatile chemicals or blends may also be used to detect pest outbreaks. Biosensors coupled to information networks will provide real-time monitoring and surveillance of crops or stored produce and hence early warning of emerging problems and new invasive species. Challenges remain in the dissemination of new technologies and information to resource poor farmers in developing countries, although the rapid extension of the internet, mobile phones and other communication networks will provide new opportunities. Defining the genetic and molecular basis of innate plant immunity has been a major advance in plant biology with the potential to identify new targets for intervention via novel chemistry or genetic modification (GM). Identification of regulatory genes, signal molecules, pathways and networks controlling induced plant defence should lead to the development of a new generation of defence modulators, delivered either as crop protection products, or via biological agents on seeds or in the root zone. There should also be opportunities to select more responsive crop genotypes, or to develop transgenic crops tailored to respond to specific chemical cues or molecular patterns diagnostic for particular biotic threats. Sequencing of the genomes of the major crop species and their wild relatives will expand enormously the known gene pool and diversity of genetic resources available for plant breeders to access. It should be possible to identify genomic regions and genes conferring more durable, quantitative resistance to pathogens. The breeding cycle will be accelerated by high-throughput phenotyping and more efficient selection of resistance traits using within-gene markers. GM approaches will facilitate pyramiding (combining) resistance genes with different specificities and modes of action, thereby reducing the risk of directional selection for virulence. Analysis of the genomes of plant pathogens and invertebrate pests is already providing new information on genes, gene families and processes involved in host colonization and pathogenicity. Comparative genomics of species with diverse host ranges, contrasting feeding habits and different pathogenic lifestyles will identify new targets for inhibiting pest attack and aid the development of novel antimicrobial drugs and pesticides. Understanding the natural ecology of pests and pathogens, such as the factors determining host location, resource exploitation and interactions with other organisms, will improve our ability to manipulate behaviour, or exploit natural enemies or other antagonists of pest species. Volatile signals, either from natural plant sources, or engineered in transgenic crops, will be more widely used to modify pest behaviour. It may also be possible to manipulate microbial communities regulating pathogen populations and activity, and thereby recruit and retain more effective biocontrol agents. Insights into the natural diversity and activity of soil and microbial populations in the zones surrounding roots and seeds will provide new information on mechanisms of suppression regulating pest species. Fully effective interventions are unlikely, due to the complexity and diversity of the soil system, but there should be progress towards integrated control regimes combining more resistant crop genotypes (either selected or GM) with targeted management of natural suppressive processes. Harnessing new technologies and knowledge to create more durable resistant crops and sustainable disease and pest management systems will require improved understanding of the factors driving pest and pathogen adaptation and evolution. There must also be an increased emphasis on translational research and delivery, and developing strategies appropriate for lower-input production systems, if the second ‘green revolution’ is to become a reality.

Under lowland conditions there is evidence to indicate that animals consuming ryegrasses bred for elevated water-soluble carbohydrate (WSC) concentrations are able to utilize the protein in their diet more efficiently, resulting in increased live-weight gain, milk production and lower loss of N. The current study evaluated the effects on upland sheep production of grazing two cultivars of perennial ryegrass nominally differing in WSC content. Replicate plots (n=4) of a cultivar bred for elevated levels of WSC (AberDart) and a control cultivar (Fennema) were grazed by ewes and lambs (pre-weaning) and by lambs only (post-weaning). Target surface sward heights of 40 and 60–70 mm were maintained during the pre-weaning and post-weaning periods, respectively. No differences were found in the WSC concentration of the two swards during either the pre-weaning or post-weaning periods. However, cultivar AberDart had a significantly lower fibre concentration during both periods (P<0·05), and a higher digestibility of organic matter in dry matter (DOMD) value during the post-weaning period (P<0·05). There was no cultivar effect of treatment on lamb growth during the pre-weaning period, but lamb live-weight gain was significantly higher for those grazing AberDart than Fennema during the post-weaning period (200 g/d v. 125 g/d; s.e.d.=26·5 g/d; P<0·01), leading to a greater proportion of lambs selected for slaughter by the end of September (0·99 v. 0·70 respectively; s.e.d.=0·062; P<0·05). The improved performance for lambs grazing AberDart relative to those grazing Fennema indicates that advances in plant breeding have the potential to improve the efficiency and profitability of lamb production in the uplands. However, additional research is required to explore the extent to which growing conditions in marginal environments influence the expression of traits.

Forty Holstein dairy cows in their first and second lactations were used from 4 weeks prepartum to 10 weeks postpartum to investigate the effects of feeding ruminally protected methionine and choline on plasma metabolites. Cows were randomly assigned to one of the following treatments in a 2×2 factorial design 4 weeks before their expected calving dates, using randomized blocks based on parity: no supplement (control), 18 g/d of rumen-protected methionine (RPM) product, 60 g/d of rumen-protected choline (RPC) product, or 18 g/d of RPM+60 g/d of RPC. Treatments did not affect plasma triglycerides, glucose, total protein, nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), plasma urea nitrogen (PUN) or aspartate aminotransferase (AST) during the prepartum period. For postpartum plasma NEFA concentrations, there were interactions between RPC or RPM and week postpartum. Feeding RPM increased plasma AST concentrations (P<0·05) and decreased plasma protein concentrations (P<0·05) in postpartum cows. After calving, feeding RPC increased (P<0·05) dry matter intake (DMI), milk yield, 40 g/kg fat-corrected milk (FCM) yield and energy-corrected milk (ECM) yield. This suggests that supplemental RPC can improve lactation performance of dairy cows.

Animal recording is an interactive process that involves several practices. The efficiency of the process is essential to ensure the utility of outcomes necessary for sustainable participation. Most evaluation approaches define efficiency in economic terms. Animal recording systems lack outputs of direct economic benefits; hence, efficiency evaluation based on utility derived from the records would be more laudable. In that case, a system is considered efficient when outcome-utility-dependent participation is sustained. Approaches for evaluating efficiency based on the utility of outputs are, however, unavailable. The current study presents an approach for evaluating the efficiency of animal recording based on output utility using the institutional analysis and development framework. The approach evaluates efficiency by incorporating institutional issues influencing the operations of the system and its outcomes. It considers animal recording as an action arena with various actors in three action situations, namely: animal identification and registration, pedigree and performance recording and animal evaluation and information utilization. The variables include the positions occupied by actors, their actions, the outcomes associated with the actions, the level of control over choice, available information and the cost and benefits of engagement. As an interactive process, animal recording has rules that order relationships between actors. It also exists within a biophysical system and community whose attributes, combined with the rules, influence the actions and outcomes of recording. These are evaluated by looking at rule formation structures, enforcement and compliance and the level of interaction between the recording system and other biophysical characteristics and the community for their effects on outcomes, their utility and sustainability of recording. Participatory tools, Stakeholder matrix and Venn diagrams are used to identify the variables, quantify their interactions and link them to outputs. The applicability of the approach is tested using a case where information systems are imperfect. The approach successfully identifies missing actors within the action arena, poor rule conformance due to weak enforcement agencies and the absence of rules that govern outcomes and ensure the utility of outcomes as hindrances to the utility of recording and hence the efficiency of the system. It may therefore be used to evaluate the efficiency of systems whose outputs do not have a direct market value and in situations where quantitative market information is scarce.

The success of poultry meat production has been strongly related to improvements in growth and carcass yield, mainly by increasing breast proportion and reducing carcass fat. Conventional laboratory techniques for determining carcass composition are expensive, cumbersome and time consuming. These disadvantages have prompted a search for alternative methods. In this respect, the potential benefits from modelling growth are considerable. Neural networks (NNs) are a relatively new option for modelling growth in animal production systems. One self-organizing sub-model of artificial NN is the group method of data handling-type NN (GMDH-type NN). The present study aimed at applying the GMDH-type NNs to data from two studies with broilers in order to predict carcass energy (CEn, MJ/g) content and relative growth (g/g of body weight) of carcass components (carcass protein, breast muscle, leg and thigh muscles, carcass fat, abdominal fat, skin fat and visceral fat). The effective input variables involved in the prediction of CEn and carcass fat content using data from the first study were dietary metabolizable energy (ME, kJ/kg), crude protein (CP, g/kg of diet), fat (g/kg of diet) and crude fibre (CF, g/kg of diet). For data from the second study, the effective input variables involved in the prediction of carcass components were dietary ME (MJ/kg), CP (g/kg of diet), methionine (g/kg of diet), lysine (g/kg of diet) and body weight (kg). Quantitative examination of the goodness of fit, using R2 and error measurement indices, for the predictive models proposed by the GMDH-type NN revealed close agreement between observed and predicted values of CEn and carcass components.

The objective of the current study was to estimate heritability and genetic correlations between cystic ovarian disease (COD), foot and leg diseases (FLD) and displaced abomasum (DA) within the first three lactations of Holstein dairy cows. The 57 301 lactation records of dairy cows on 20 large dairy herds in Iran between January 2005 and June 2009 were analysed with three-trait threshold animal models, using Gibbs sampling methodology. The final model included the fixed class effects of herd-year, season of calving, the linear covariate effect of age at calving and additive direct genetic effect of animal. Posterior means of heritability in first, second and third lactations were 0·15, 0·18 and 0·22, respectively, for FLD; 0·09, 0·11, and 0·13 for COD; 0·05, 0·06, and 0·08 for DA. Posterior means of genetic correlations between diseases were low (from 0·03 to 0·14), within lactations; the largest estimates were for FLD and DA, and the lowest involved FLD and COD. Positive genetic correlations between diseases suggest that some general disease resistance factor with a genetic component exists. The results of the present study indicated the importance of health traits for considering in the selection index of Iranian Holstein dairy cows.

EU milk quota deregulation has forced many farmers to reconsider the factors that will limit milk production into the future. Factors other than milk quota such as land, labour, capital, stock, etc. will become the limiting factor for many in a post-EU milk quota scenario. While it can be postulated what the limits to production will be in a post-quota scenario, how farmers react will determine the future direction of the industry. In order to determine the future attitudes and intentions and to identify the key factors influencing farmers who intend to expand, exit, remain static or contract their businesses in the future, a survey of a large group of Irish commercial dairy farmers was carried out. The telephone survey sample was chosen randomly, based on a proportional representation of suppliers to the largest milk processor in Ireland. The sample (780 suppliers) was broken down by quota size (five quota categories, Q1–Q5), supplier region and system of production. The sample was analysed to determine the effect of key survey variables on the future intentions of dairy farmers. The survey was completed by 659 suppliers (0·82 of the sample). The proportions of farmers intending to expand were 0·28, 0·47, 0·61, 0·61 and 0·56, respectively, for Q1–Q5, while the proportions intending to exit were 0·27, 0·18, 0·08, 0·09 and 0·08, respectively. Farmers who were intent on expanding had larger total farm areas, larger milk tank capacity per litre of milk quota, more modern milking facilities, more available cow housing and more housing that could be converted at a relatively low cost and were more likely to have a successor. Of those expanding, 0·60 wanted milk quotas abolished, while 0·36 of those planning to exit wanted milk quotas abolished. The level of expansion was affected by business scale, dairy stocking rate, the additional labour required with expansion and total and milking platform farm size.

The concepts of control charts, an important tool in statistical process control, are commonly used for monitoring industrial production processes. In the context of precision livestock farming, their use has been demonstrated by many, although the statistical properties of livestock process data often do not comply with the basic assumptions of such control charts. The focus of the current review is on the most important aspects, recommendations, pitfalls and opportunities for the development and performance of control charts on livestock process data. An important hurdle to tackle is the statistical characteristics of the raw livestock process data which are mostly violating the control charts’ assumptions. An integrated approach, like synergistic control, appears to be promising in handling this issue. The availability of real-time on-farm validation of proposed systems will be crucial for lifting them from the potential level to direct practical relevance.

The UK dairy sector has undergone considerable structural change in recent years, with a decrease in the number of producers accompanied by an increased average herd size and increased concentrate use and milk yields. One of the key drivers to producers remaining in the industry is the profitability of their herds. The current paper adopts a holistic approach to decomposing the variation in dairy profitability through an analysis of net margin data explained by physical input–output measures, milk price variation, labour utilization and managerial behaviours and characteristics. Data are drawn from the Farm Business Survey (FBS) for England in 2007/08 for 228 dairy enterprises. Average yields are 7100 litres/cow/yr, from a herd size of 110 cows that use 0·56 forage ha/cow/yr and 43·2 labour h/cow/yr. An average milk price of 22·57 pence per litre (ppl) produced milk output of £1602/cow/yr, which after accounting for calf sales, herd replacements and quota leasing costs, gave an average dairy output of £1516/cow/yr. After total costs of £1464/cow/yr this left an economic return of £52/cow/yr (0·73 ppl) net margin profit. There is wide variation in performance, with the most profitable (as measured by net margin per cow) quartile of producers achieving 2000 litres/cow/yr more than the least profitable quartile, returning a net margin of £335/cow/yr compared to a loss of £361/cow/yr for the least profitable. The most profitable producers operate larger, higher yielding herds and achieve a greater milk price for their output. In addition, a significantly greater number of the most profitable producers undertake financial benchmarking within their businesses and operate specialist dairy farms. When examining the full data set, the most profitable enterprises included significantly greater numbers of organic producers. The most profitable tend to have a greater reliance on independent technical advice, but this finding is not statistically significant. Decomposing the variation in net margin performance between the most and least profitable groups, an approximate ratio of 65:23:12 is observed for higher yields: lower costs: higher milk price. This result indicates that yield differentials are the key performance driver in dairy profitability. Lower costs per cow are dominated by the significantly lower cost of farmer and spouse labour per cow of the most profitable group, flowing directly from the upper quartile expending 37·7 labour h/cow/yr in comparison with 58·8 h/cow/yr for the lower quartile. The upper quartile's greater milk price is argued to be achieved through contract negotiations and higher milk quality, and this accounts for 0·12 of the variation in net margin performance. The average economic return to the sample of dairy enterprises in this survey year was less than £6000/farm/yr. However, the most profitable quartile returned an average economic return of approximately £50 000 per farm/yr. Structural change in the UK dairy sector is likely to continue with the least profitable and typically smaller dairy enterprises being replaced by a smaller number of expanding dairy production units.

Throughout the 21st century, livestock diseases will impact upon the productivity of domesticated livestock and compromise the ability to feed a growing global population. The focus of the present review is to outline how the recent rapid expansion of genetic sequence data available for both pathogens and hosts can be exploited to develop new tools to improve the ways in which livestock diseases can be controlled. In the post-genomics era of the future, there will be a more intimate understanding of the way in which pathogens interact with their hosts and the key molecules that define host–pathogen relationships; knowledge that can be utilized to generate novel diagnostics and vaccination strategies. However, experience from the global rinderpest eradication programme highlights that effective disease control is a multifactorial process. Clearly, appropriate new therapeutic and diagnostic tools can play a critical role in our ability to monitor and limit the spread of diseases. However, adequate resources are also required: these are principally financial and also include the availability of trained personnel and veterinary infrastructure; international cooperation, transparency between different countries and sharing of epidemiological data and ownership of disease; acceptance of the difference in perception of importance of diseases in the developed world v. the developing world.

The current study investigated the effects of supplementing rumen-protected choline (RPC) on metabolic profile, selected liver constituents and transcript levels of selected enzymes, transcription factors and nuclear receptors involved in mammary lipid metabolism in dairy goats. Eight healthy lactating goats were studied: four received no choline supplementation (CTR group) and four received 4 g RPC chloride/day (RPC group). The treatment was administered individually starting 4 weeks before expected kidding and continuing for 4 weeks after parturition. In the first month of lactation, milk yield and composition were measured weekly. On days 7, 14, 21 and 27 of lactation, blood samples were collected and analysed for glucose, β-hydroxybutyrate, non-esterified fatty acids and cholesterol. On day 28 of lactation, samples of liver and mammary gland tissue were obtained. Liver tissue was analysed for total lipid and DNA content; mammary tissue was analysed for transcripts of lipoprotein lipase (LPL), fatty acid synthase (FAS), sterol regulatory binding proteins 1 and 2, peroxisome proliferator-activated receptor γ and liver X receptor α. Milk yield was very similar in the two groups, but RPC goats had lower (P<0·05) plasma β-hydroxybutyrate. The total lipid content of liver was unaffected (P=0·890), but the total lipid/DNA ratio was lower (both P<0·05) in RPC than CTR animals. Choline had no effect on the expression of the mammary gland transcripts involved in lipid metabolism. The current plasma and liver data indicate that choline has a positive effect on liver lipid metabolism, whereas it appears to have little effect on transcript levels in mammary gland of various proteins involved in lipid metabolism. Nevertheless, the current results were obtained from a limited number of animals, and choline requirement and function in lactating dairy ruminants deserve further investigation.

Ten Polwarth×Texel lambs (26±2·1 kg live weight (LW)), housed in metabolism cages and offered ryegrass (Lolium multiflorum) ad libitum, were used in a 5×5 Latin Square experiment to evaluate the effect of supplement type on digestion processes and on amino acid and energy supplies. Five of the 10 lambs were fitted with a rumen catheter and duodenal cannulae. Treatments included no supplement (control); 7 g/kg LW daily of cassava meal (Manihot esculenta, high-starch low-nitrogen (HS-LN)), cassava meal plus corn gluten meal (2:1, high-starch high-undegradable N (HS-UN)), cassava meal plus calcium caseinate (2·8:1, high-starch high-degradable N (HS-DN)) or corn gluten feed (low-starch high-degradable N (LS-DN)). Total intake of dry matter (DM), organic matter (OM) and N, as well as digestible OM intake were increased with HS-UN, HS-DN and LS-DN (P⩽0·050). Forage DM intake was reduced by HS-LN (P=0·030). Apparent digestibility of DM and OM was increased by HS-LN and HS-DN (P⩽0·038). Digestibility of neutral detergent fibre (NDF) and OM true digestibility were similar for all treatments. Supplementation with HS-LN decreased duodenal flux of total N, amino acid N, ammonia N and feed residual N (P⩽0·023). None of the supplements affected rumen microbial protein entering the small intestine, whereas the efficiency of rumen microbial protein synthesis (EMPS) was reduced by HS-LN and HS-DN (P⩽0·036). Ruminal degradability of dietary N (RDN) was increased by HS-LN, HS-DN and LS-DN (P⩽0·050). In conclusion, supplementing lambs fed ryegrass with degradable or undegradable high-protein concentrate increased the amino acid supply without affecting the supply of digestible energy, regardless of either the starch content or the degree of ruminal degradability of the protein source. These results indicate that supplementation of ryegrass-based diets should include both starch and protein sources.