Selenium supplementation of lactating dairy cows: effects on milk production and total selenium content and speciation in blood, milk and cheese

Forty multiparous Holstein cows were used in a 16-week continuous design study to determine the effects of either selenium (Se) source, selenised yeast (SY) (derived from a specific strain of Saccharomyces cerevisiae CNCM 1-3060) or sodium selenite (SS), or Se inclusion rate in the form of SY in the diets of lactating dairy cows on the Se concentration and speciation in blood, milk and cheese. Cows received ad libitum a total mixed ration (TMR) with a 1 : 1 forage: concentrate ratio on a dry matter (DM) basis. There were four diets (T-1 to T-4), which differed only in either source or dose of Se additive. Estimated total dietary Se for T, (no supplement), T-2 (SS), T-3 (SY) and T-4 (SY) was 0.16, 0.30, 0.30 and 0.45 mg/kg DM, respectively. Blood and milk samples were taken at 28-day intervals and at each time point there were positive linear effects of Se in the form of SY on the Se concentration in blood and milk. At day 112 blood and milk Se values for T-1 to T-4 were 177, 208, 248 and 279 +/- 6.6 and 24, 38, 57 and 72 +/- 3.7 ng/g fresh material, respectively, and indicate improved uptake and incorporation of Se from SY. In whole blood, selenocysteine (SeCys) was the main selenised amino acid and the concentration of selenomethionine (SeMet) increased with the increasing inclusion rate of SY In milk, there were no marked treatment effects on the SeCys content, but Se source had a marked effect on the concentration of SeMet. At day 112 replacing SS (T-2) with SY (T-3) increased the SeMet concentration of milk from 36 to 111 ng Se/g and its concentration increased further to 157ng Se/g dried sample as the inclusion rate of SY increased further (T-4) to provide 0.45 mg Se/kg TMR. Neither Se source nor inclusion rate affected the keeping quality of milk. At day 112 milk from T-1, T-2 and T-3 was made into a hard cheese and Se source had a marked effect on total Se and the concentration of total Se comprised as either SeMet or SeCys. Replacing SS (T-2) with SY (T-3) increased total Se, SeMet and SeCys content in cheese from 180 to 340 ng Se/g, 57 to 153 ng Se/g and 52 to 92 ng Se/g dried sample, respectively. The use of SY to produce food products with enhanced Se content as a means of meeting the Se requirements is discussed

Farming and food production and development in the Shropshire Hills Environmentally Sensitive Area, 1997-2008

European agricultural and environmental policy has evolved considerably over the last 15 years. In this paper the changes in farm businesses in an Environmentally Sensitive Area in England are evaluated based on two surveys with the same farmers at the start and end of this period. The rate of participation in the environmental scheme had increased significantly at a time when Government led goals in this area had developed and become more output focussed. A combination of policy, market and animal health status changes had encouraged a number to leave cattle production, and though remaining with stock and grass they had decided against any extensive development in the direction of pluriactivity – with or without Government encouragement. This left the future of this group in some uncertainty given that two significant forms of financial support, the environmental scheme and the Hill Farm Allowance, were due to close.

The in vitro gas production technique: limitations and opportunities

This preface outlines the reasons for undertaking the special issue, comments on the review process that was used, provides a brief summary of the papers included and discusses some of the implications of these papers on in vitro gas technique methodology and its applications.

Modelling the likely impact of healthy eating guidelines on agricultural production and land use in England and Wales

Quadratic programming techniques were applied to household food consumption data in England and Wales to estimate likely changes in diet under healthy eating guidelines, and the consequences this would have on agriculture and land use in England and Wales. The first step entailed imposing nutrient restrictions on food consumption following dietary recommendations suggested by the UK Department of Health. The resulting diet was used, in a second step as a proxy for demand in agricultural commodities, to test the impact of such a scenario on food production and land use in England and Wales and the impacts of this on agricultural landscapes. Results of the diet optimisation indicated a large drop in consumption of foods rich in saturated fats and sugar, essentially cheese and sugar-based products, along with lesser cuts of fat and meat products. Conversely, consumption of fruit and vegetables, cereals, and flour would increase to meet dietary fibre recommendations. Such a shift in demand would dramatically affect production patterns: the financial net margin of England and Wales agriculture would rise, due to increased production of high market value and high economic margin crops. Some regions would, however, be negatively affected, mostly those dependent on beef cattle and sheep production that could not benefit from an increased demand for cereals and horticultural crops. The effects of these changes would also be felt in upstream industries, such as animal feed suppliers. While arable dominated landscapes would be little affected, pastoral landscapes would suffer through loss of grazing management and, possibly, land abandonment, especially in upland areas.

Evaluating the effects of tannins on the extent and rate of in vitro measured gas and methane production using the Automated Pressure Evaluation System (APES)

An in vitro study was conducted to investigate the effect of tannins on the extent and rate of gas and methane production, using an automated pressure evaluation system (APES). In this study three condensed tannins (CT; quebracho, grape seed and green tea tannins) and four hydrolysable tannins (HT; tara, valonea, myrabolan and chestnut tannins) were evaluated, with lucerne as a control substrate. CT and HT were characterised by matrix assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF-MS). Tannins were added to the substrate at an effective concentration of 100 g/kg either with or without polyethylene glycol (PEG6000), and incubated for 72 h in pooled, buffered rumen liquid from four lactating dairy cows. After inoculation, fermentation bottles were immediately connected to the APES to measure total cumulative gas production (GP). During the incubation, 11 gas samples were collected from each bottle at 0, 1, 4, 7, 11, 15, 23, 30, 46, 52 and 72 h of incubation and analysed for methane. A modified Michaelis-Menten model was fitted to the methane concentration patterns and model estimates were used to calculate the total cumulative methane production (GPCH4). GP and GPCH4 curves were fitted using a modified monophasic Michaelis-Menten model. Addition of quebracho reduced GP (P=0.002), whilst the other tannins did not affect GP. Addition of PEG increased GP for quebracho (P=0.003), valonea (P=0.058) and grape seed tannins (P=0.071), suggesting that these tannins either inhibited or tended to inhibit fermentation. Addition of quebracho and grape seed tannins also reduced (P≤0.012) the maximum rate of gas production, indicating that microbial activity was affected. Quebracho, valonea, myrabolan and grape seed decreased (P≤0.003) GPCH4 and the maximum rate (0.001≤ P≤ 0.102) of CH4 production. Addition of chestnut, green tea and tara tannins did not affect total gas nor methane production. Valonea and myrabolan tannins have most promise for reducing methane production as they had only a minor impact on gas production.

Production of attaching-effacing lesions in ligated large intestine loops of 6-month-old sheep by Escherichia coli O157:H7

Shiga-toxigenic Escherichia coli O157:H7 (STEC O157:H7) is associated with potentially fatal human disease, and a persistent reservoir of the organism is present in some farm animal species, especially cattle and sheep. The mechanisms of persistent colonisation of the ruminant intestine by STEC O157:H7 are poorly understood but may be associated with intimate adherence to eukaryotic cells. Intimate adherence, as evidenced by induction of attaching-effacing (AE) lesions by STEC O157, has been observed in 6-day-old conventional lambs after deliberate oral infection but not in older animals. Thus, the present study used a ligated intestinal loop technique to investigate whether STEC O157:H7 and other attaching-effacing E. coli may adhere intimately to the sheep large intestinal mucosa. To do this, four STEC O157:H7 strains, one STEC 026:K60:H11 and one Shiga toxin-negative E. coli O157:H7 strain, suspended in either phosphate-buffered saline or Dulbecco's modified Eagle's medium, were inoculated into ligated spiral colon loops of each of two lambs. The loops were removed 6 h after inoculation, fixed and examined by light and electron microscopy. AE lesions on the intestinal mucosa were produced by all the inoculated strains. However, the lesions were sparse and small, typically comprising bacterial cells intimately adhered to a single enterocyte, or a few adjacent enterocytes. There was little correlation between the extent of intimate adherence in this model and the bacterial cell density, pre-inoculation growth conditions of the bacteria or the strain tested.

Precision placement of fertiliser for optimising the early nutrition of vegetable crops: a review of the implications for the yield and quality of crops, and their nutrient use efficiency

The research outlined in this paper highlights the importance of the early nutrition of vegetable crops, and its long-term effects on their subsequent growth and development. Results are also presented to demonstrate how the nutrient supply during the establishment stages of young seedlings and transplants can be enhanced by targeting fertiliser to a zone close to their developing roots. Three different precision fertiliser placement techniques are compared for this purpose: starter, band or side-injected fertiliser. The use of each of these methods consistently produced the same (or greater) yields at lower application rates than those from conventional broadcast applications, increasing the apparent recovery of N, P and K, and the overall efficiency of nutrient use, while reducing the levels of residual nutrients in the soil. Starter fertilisers also advanced the maturity of some crops, and enhanced produce quality by increasing the proportions of the larger and/or more desirable marketable grades. The benefits of the different placement techniques are illustrated with selected examples from research at Warwick HRI using different vegetable crops, including lettuce, onion and carrot.

The role of animal nutrition in designing optimal foods of animal origin as reviewed by the COST Action Feed for Health (FA0802)

This review provides an overview of the main scientific outputs of a network (Action) supported by the European Cooperation in Science and Technology (COST) in the field of animal science, namely the COST Action Feed for Health (FA0802). The main aims of the COST Action Feed for Health (FA0802) were: to develop an integrated and collaborative network of research groups that focuses on the roles of feed and animal nutrition in improving animal wellbeing and also the quality, safety and wholesomeness of human foods of animal origin; to examine the consumer concerns and perceptions as regards livestock production systems. The COST Action Feed for Health has addressed these scientific topics during the last four years. From a practical point of view three main scientific fields of achievement can be identified: feed and animal nutrition; food of animal origin quality and functionality and consumers’ perceptions. Finally, the present paper has the scope to provide new ideas and solutions to a range of issues associated with the modern livestock production system.

Impact of variation in structure of condensed tannins from sainfoin (Onobrychis viciifolia) on in vitro ruminal methan production and fermentation characteristics

Our study investigated the effects of condensed tannins (CT) on rumen in vitro methane (CH4) production and fermentation characteristics by incubating lucerne in buffered rumen fluid in combination with different CT extracts at 0 (control), 40, 80 and 120 g CT/kg of substrate DM. Condensed tannins were extracted from four sainfoin accessions: Rees ‘A’, CPI63763, Cotswold Common and CPI63767. Gas production (GP) was measured using a fully automated GP apparatus with CH4 measured at distinct time points. Condensed tannins differed substantially in terms of polymer size and varied from 13 (Rees ‘A’) to 73 (CPI63767) mean degree of polymerization, but had relatively similar characteristics in terms of CT content, procyanidin: prodelphinidin (PC: PD) and cis:trans ratios. Compared to control, addition of CT from CPI63767 and CPI63763 at 80 and 120 g CT/kg of substrate DM reduced CH4 by 43% and 65%, and by 23% and 57%, respectively, after 24-h incubation. Similarly, CT from Rees ‘A’ and Cotswold Common reduced CH4 by 26% and 46%, and by 28% and 46% respectively. Addition of increasing level of CT linearly reduced the maximum rates of GP and CH4 production, and the estimated in vitro organic matter digestibility. There was a negative linear and quadratic (p < 0.01) relation between CT concentration and total volatile fatty acid (VFA) production. Inclusion of 80 and 120 g CT/kg of substrate DM reduced (p < 0.001) branched-chain VFA production and acetate: propionate ratio and was lowest for CPI63767. A decrease in proteolytic activity as indirectly shown by a change in VFA composition favouring a shift towards propionate and reduction in branched-chain VFA production varied with type of CT and was highest for CPI63767. In conclusion, these results suggest that tannin polymer size is an important factor affecting in vitro CH4 production which may be linked to the CT interaction with dietary substrate or microbial cells.

Consumer attitudes to injurious pecking in free range egg production

Free range egg producers face continuing problems from injurious pecking (IP) which has financial consequences for farmers and poor welfare implications for birds. Beak trimming has been practised for many years to limit the damage caused by IP, but with the UK Government giving notification that they intend to ban beak trimming in 2016, considerable efforts have been made to devise feasible housing, range and management strategies to reduce IP. A recent research project investigated the efficacy of a range of IP reducing management strategies, the mean costs of which came to around 5 pence per bird. Here, the results of the above project’s consumer survey are presented: consumers’ attitudes to free range egg production are detailed showing that, whilst consumers had a very positive attitude towards free range eggs, they were especially uninformed about some aspects of free range egg production. The contingent valuation technique was used to estimate the price premium consumers would be prepared to pay to ensure that hens do not suffer from IP: this was calculated as just over 3% on top of the prevailing retail price of free range eggs. These findings reinforce other studies that have found that whilst consumers are not generally well-informed about certain specific welfare problems faced by animals under free range conditions, they are prepared to pay to improve animal welfare. Indeed, the study findings suggest that producers could obtain an additional price premium if they demonstrate the welfare provenance of their eggs, perhaps through marketing the eggs as coming from birds with intact beaks. This welfare provenance issue could usefully be assured to consumers by the introduction of a mandatory, single, accredited EU-wide welfare-standards labelling scheme.