In Western countries the dietary guidance emphasizes the need to decrease the intake of saturated fatty acids and to replace them with polyunsaturated fatty acids (PUFA), particularly long chain n-3 PUFA (LC-PUFA). The production of poultry meat having a lower fat content and healthier fatty acid (FA) profile is a hot topic for the poultry industry, and the possibility to identify genotypes able to produce meat with a higher LC-PUFA content deserves attention. The aims of the present study were to evidence in chicken (i) a genotype-related different expression of the desaturating enzymes delta-6 (Δ6, EC 1.14.99.25), delta-5 (Δ5, EC 1.14.19.) and delta-9 (Δ9, EC 1.14.19.1); (ii) the impact of the hypothesized different expression on the meat FA composition; (iii) the distribution of desaturase products in the different lipid classes. Slow (SG), medium (MG) and fast (FG) growing chickens fed the same diet were evaluated either for the relative expression of FADS1, FADS2 and SCD1 genes in liver (by q-PCR), or for the FA composition of breast meat. MG and particularly SG birds showed a greater expression of FADS2 and FADS1 genes, a higher Δ6 and Δ5 activity (estimated using desaturase indices), and consequently a higher LC-PUFA content in the breast meat than FG birds. The relationship between genotype and desaturating ability was demonstrated, with a significant impact on the PUFA content of breast meat. Due to the high consumption rate of avian meat, the identification of the best genotypes for meat production could represent an important goal not only for the food industry, but also for the improvement of human nutrition.

In dairy cattle type classification schemes, heifers are condition scored (CS) only once during their first lactation. Although genetic analysis of condition-score changes is not possible using an animal model, the data can be analysed as repeated observations on the sire.

CS records for 100 078 Holstein Friesian heifers, the progeny of 797 sires, were available. Sires differed in the shape of the regression of mean daughter CS on stage of lactation at both the phenotypic and genetic level. Genetic analysis was carried out using a random regression model (RRM) which can account for differences between sires in the shape of the CS curves. CS curves for individual sires were modelled using a cubic polynomial.

Heritability estimates for CS at each stage of lactation generally increased through the lactation from 0·20 in stage 2 (days in milk 31 to 60) to 0·28 in later lactation stages. Genetic correlations between CS at different stages were generally high (0·80), with the exception of correlations with stage 1 (days in milk 1 to 30) which decreased to 0·63 with stages 6 and 7, suggesting that CS at stage 1 is under different biological control from CS at other stages of the lactation. Using RRM, sire estimated breeding values (EBVs) for CS at each stage of the lactation were estimated. Sire rankings on EBV at each stage were seen to change through early, mid and later lactation stages.

During weeks 3 to 26 of lactation, two groups of 24 cows were offered either a 60:40 (high) or a 40:60 (low) ratio of concentrate dry matter:silage dry matter. The 40:60 diet was restricted to give the same daily metabolizable energy and crude protein intake. The hooves of half the cows on each diet were trimmed prior to the experiment, the other half remaining untrimmed. The high concentrate ratio significantly increased locomotion score (high scores indicating poorer locomotion), and the number and duration of clinical cases of lameness. Trimming of hooves significantly reduced the number and diiration of clinical cases. Hoof growth was significantly increased by trimming. Hoof hardness was significantly reduced by the high concentrate ratio. The low concentrate ratio had 8/24 cows lame for an average of 3·3 weeks compared with 11 cows for 3·9 weeks on the high ratio. There were 7/24 trimmed cows lame for 3·1 weeks compared with 12 untrimmed cows lame for 4·2 weeks. The main hoof lesions were solar ulcers and heel erosion. There was no significant effect on milk yield, but milk protein was signficantly increased by the high concentrate ratio. Condition score was significantly negatively correlated with locomotion score.

With the growing human population, and their improving wealth, it is predicted that there will be significant increases in demand for livestock products (mainly meat and milk). Recent years have demonstrated that the growth in livestock production has generally had significant impacts on wildlife worldwide; and these are, usually, negative. Here I review the interactions between livestock and wildlife and assess the mechanisms through which these interactions occur. The review is framed within the context of the socio-ecological system whereby people are as much a part of the interaction between livestock and wildlife as the animal species themselves. I highlight areas of interaction that are mediated through effects on the forage supply (vegetation) – neutral, positive and negative – however, the review broadly analyses the impacts of livestock production activities. The evidence suggests that it is not the interaction between the species themselves but the ancillary activities associated with livestock production (e.g. land use change, removal of predators, provision of water points) that are the major factors affecting the outcome for wildlife. So in future, there are two key issues that need to be addressed – first, we need to intensify livestock production in areas of ‘intensive’ livestock production in order to reduce the pressure for land use change to meet the demand for meat (land sparing). And second, if wildlife is to survive in areas where livestock production dominates, it will have to be the people part of the socio-ecological system that sees the benefits of having wildlife co-exist with livestock on farming lands (land sharing and win-win).

The livestock sector is one of the fastest growing subsectors of the agricultural economy and, while it makes a major contribution to global food supply and economic development, it also consumes significant amounts of natural resources and alters the environment. In order to improve our understanding of the global environmental impact of livestock supply chains, the Food and Agriculture Organization of the United Nations has developed the Global Livestock Environmental Assessment Model (GLEAM). The purpose of this paper is to provide a review of GLEAM. Specifically, it explains the model architecture, methods and functionality, that is the types of analysis that the model can perform. The model focuses primarily on the quantification of greenhouse gases emissions arising from the production of the 11 main livestock commodities. The model inputs and outputs are managed and produced as raster data sets, with spatial resolution of 0.05 decimal degrees. The Global Livestock Environmental Assessment Model v1.0 consists of five distinct modules: (a) the Herd Module; (b) the Manure Module; (c) the Feed Module; (d) the System Module; (e) the Allocation Module. In terms of the modelling approach, GLEAM has several advantages. For example spatial information on livestock distributions and crops yields enables rations to be derived that reflect the local availability of feed resources in developing countries. The Global Livestock Environmental Assessment Model also contains a herd model that enables livestock statistics to be disaggregated and variation in livestock performance and management to be captured. Priorities for future development of GLEAM include: improving data quality and the methods used to perform emissions calculations; extending the scope of the model to include selected additional environmental impacts and to enable predictive modelling; and improving the utility of GLEAM output.

Divergent breeding lines of Romney sheep, selected as lambs for consistently low or high faecal worm egg count (FEC) following natural multispecific challenge by nematode parasites, have been maintained at Wallaceville Animal Research Centre since 1979. From the start of the trial until 1992, 821 and 736 experimental lambs in lines selected for increased resistance (R) and increased susceptibility (S), respectively, were generated, with the use of 44 different sires. In order to assess genetic responses to selection, FEC and productivity data were analysed using restricted maximum likelihood procedures. By 1988 the two lines had diverged in average loge (FEC+100) by 0·67 log units, and by 1992 divergence had increased to 1·48 log units, representing 2·90 genetic standard deviations of divergence. No significant correlated responses were observed in live weights. However, by 1992 the mean score for breech soiling (dags) in the R line was proportionally 0·41 greater than in the S line (F < 0·001). Yearling fleece weight was proportionally 0·15 greater in S-line than in R-line animals when grazed together under identical levels of challenge (P < 0·001) but the lines did not differ significantly in fleece weight when they were grazed apart. The R line had significantly higher reproductive success than the S line (P < 0·05), as measured by lambs weaned per ewe mated (1·01 v. 0·92, respectively). It is concluded that selective breeding can change the degree of resistance or susceptibility to nematode infection in Romney sheep, and selection for productivity needs to be continued at the same time in any practical breeding programme.

One hundred and eighty piglets (24 days old, 6·0 kg live weight) were used to investigate interactions between lactose, avilamycin and inulin on growth performance and nutrient digestibility in weaned piglets. The piglets were blocked on the basis of live weight and within each block assigned to one of six dietary treatments (six replicates (pens) per treatment). The piglets were offered diets containing either a low (175 g/kg) or high (295 g/kg) lactose levels with one of the following food additives (1) 0 supplementation (2) avilamycin (60 mg/kg) or (3) inulin (15 g/kg) in a 2 × 3 factorial arrangement. The starter diets were offered for 21 days and all diets contained chromium III oxide at 150 p. p. m. There was an interaction (P < 0·05) between lactose level and both avilamycin and inulin on average daily gain (ADG) during the starter period (days 0 to 21). The pigs receiving 295 g/kg lactose level had a higher overall ADG than pigs receiving 175 g/kg lactose level. However, there was no difference between 295 g/kg lactose and 175 g/kg lactose in ADG when the diets were supplemented with avilamycin or inulin. There was an interaction between lactose level and inulin in the apparent digestibility of gross energy (GE) and nitrogen (N) (P < 0·05). The inclusion of inulin with 175 g/kg lactose increased GE digestibility compared with the 175 g/kg lactose only diet. However, the inclusion of inulin with 295 g/kg lactose had no effect on GE digestibility. The inclusion of inulin with 295 g/kg lactose reduced N digestibility compared with the inclusion of inulin at 175 g/kg lactose. However, there was no difference in N digestibility between 175 and 295 g/kg lactose only diets. In conclusion, there was no benefit in terms of pig growth rate to supplementing diets high in lactose with either inulin or avilamycin. However, the inclusion of inulin improved the energy digestibility of diets low in lactose.

An experiment was conducted with 48 dairy cows grazed in treatment groups of four, eight or 16 cows per group, whose grazing, social and resting behaviour was recorded over a 53-day period. Cows in groups of four stayed closer to their nearest neighbour, moved their head more rapidly from side to side during grazing and spent more time ruminating than cows in larger groups, suggesting that they were more vigilant against a perceived prédation risk. Cows in the group of 16 were more aggressive, maintained a greater distance to their nearest neighbour and had a faster rate of stepping while they grazed, compared with cows in smaller groups, suggesting increased inter-cow competition. They also spent longer grooming themselves, which normally acts as a displacement activity and may indicate increased stress. Cows in groups of eight had a faster biting rate when grazing than cows in small or large groups and they spent the longest time lying down. There were no effects of group size on milk production but across treatment groups the high yielding cows were the first to initiate grazing and to enter the milking parlour.

Among domestic ruminants, goats are renowned for their ability to tolerate water deprivation, water restriction and energy restriction. However, some basic questions regarding their ability to endure water restriction under heat stress are still open. Three levels of water restriction (56%, 73% and 87% of the ad libitum) were imposed on 20 cross-bred 3-year-old female goats (75% German Fawn and 25% Hair Goat) distributed into four groups, with five animals per treatment. The experiment was conducted from the beginning of July to the end of August in a farm located in the Eastern Mediterranean region of Turkey (40 m in altitude; 36 59' N, 35 18'E), in which subtropical weather conditions prevail. The average daily temperature during the experiment was 34.2°C, whereas the highest and lowest temperatures were 42°C and 23.1°C, respectively. The average relative humidity was 68.2% and wind speed was 1.2 km/h. Weekly average thermal heat indexes during the experiment were 78.3 (week 1), 79.1 (week 2), 80.1 (weak 3), 79.8 (weak 4), 81.3 (weak 5) and on average 79.7. Feed intake, heart rate, thermoregulatory responses (rectal temperature, respiration rate), blood plasma concentrations of ions (Na, K), antidiuretic hormone (ADH), metabolites (glucose, cholesterol, creatinine and urea) and behavioral aspects (standing, walking, lying) were studied over 30 days. The responses to water restriction were proportional to the level of restriction. The reductions in feed intake (up to 13%), BW (up to 4.6%) and the increases in rectal temperature (0.5°C) and breath rate (10 respirations/min) were moderate and also were far from responses encountered under severe heat and water stresses. The increase in plasma Na (from 119 to 140 mM) and ADH concentrations (from 12.6 to 17.4 pg/ml) indicates that the physiological response to water restriction was in response to mild dehydration, which also explains the increase in blood plasma concentrations of glucose, cholesterol, creatinine and urea. Behavioral responses (reduction in walking from 226 to 209 min/day and increase in lying from 417 to 457 min/day) were associated with conservation of energy or thermoregulation (reducing the exposure to direct radiation).

The branched-chain amino acids (BCAA) valine (Val) and isoleucine (Ile) are considered to be among the next-limiting amino acids for growth in piglets. In earlier studies, we estimated the standardized ileal digestible (SID) Val : Lys (lysine) requirement to be at least 70%, whereas the Ile : Lys requirement may be as low as 50%. Because the BCAA partially share a common route of catabolism, the supply of one BCAA may affect the availability of the other BCAA. Four experiments were conducted to determine the response of 6-week-old piglets to the Val supply in relation to the other BCAA. A deficient supply of Val or Ile typically results in a reduction in average daily feed intake (ADFI). Experiment 1 was designed to determine the effect of a limiting Val supply, independent of the effect on feed intake. In a dose–response study using restrictively fed piglets, nitrogen retention did not increase for an SID Val : Lys supply greater than 64%. In the remaining experiments, piglets were offered feed ad libitum using ADFI, average daily gain (ADG) and gain-to-feed ratio as response criteria. The interaction between the Val and leucine (Leu) was studied in Experiment 2 in a 2 × 2 factorial design (60% and 70% SID Val : Lys, and 111% and 165% SID Leu : Lys). Performance was considerably lower in piglets receiving 60% Val : Lys compared with those receiving 70% Val : Lys and was lowest in piglets receiving the diet with low Val and high Leu content. To further evaluate the interaction between Val and Leu, a dose–response study was carried out in which the response to Val supply was studied in combination with high Leu supply (165% Leu : Lys). Using a curvilinear-plateau model, the average SID Val : Lys requirement was 72%. However, low Val supply (60% SID Val : Lys) reduced performance by 13% to 38%, which was much greater than what we observed in earlier studies. Experiment 4 was carried out to test the hypothesis that the Val requirement is not affected by low Ile supply (50% SID Ile : Lys). Performance was not improved for Val : Lys supplies greater than 65%, which may indicate that Ile (and not Lys) was second-limiting in this study. In conclusion, the first response of piglets to deficient Val supply appears to be a reduction in ADFI, rather than a reduction in ADG or nitrogen retention. A large supply of Leu may not affect the Val requirement per se, but may aggravate the consequences of Val deficiency.

Directing protein and energy sources towards lactation is crucial to optimise milk production in sows but how this influences colostrum yield (CY) remains unknown. The aim of this study was to identify associations between CY and the sow’s use of nutrient resources. We included 37 sows in the study that were all housed, fed and managed similarly. Parity, back fat change (ΔBF), CY and performance parameters were measured. We obtained sow serum samples 3 to 4 days before farrowing and at D1 of lactation following overnight fasting. These were analysed for non-esterified fatty acids (NEFA), urea, creatinine, (iso)butyrylcarnitine (C4) and immunoglobulins G (IgG) and A (IgA). The colostrum samples collected 3, 6 and 24 h after the birth of the first piglet were analysed for their nutrient and immunoglobulins content. The technical parameters associated with CY were parity group (a; parities 1 to 3=value 0 v. parities 4 to 7=value 1) and ΔBF D85-D109 of gestation (mm) (b): CY (g)=4290–842a–113b. (R2=0.41, P<0.001). The gestation length (P<0.001) and the ΔBF between D109 and D1 of lactation (P=0.050) were identified as possible underlying factors of the parity group. The metabolic parameters associated with CY were C4 at 3 to 4 days before farrowing (a), and 10logC4 (b) and 10logNEFA (c) at D1 of lactation: CY (g)=3582–1604a+1007b−922c (R2=0.39, P=0.001). The colostrum composition was independent of CY. The negative association between CY and ΔBF D85-D109 of gestation could not be further explained based on our data. Sows that were catabolic 1 week prior to farrowing seemed unable to produce colostrum to their full potential. This was especially the case for sows with parities 4 to 7, although they had a similar feed intake, litter birth weight and colostrum composition compared with parities 1 to 3 sows. In conclusion, this study showed that parity and the use of body fat and protein reserves during late gestation were associated with CY, indicating that proper management of the sow’s body condition during late gestation could optimise the intrinsic capacity of the sow’s CY.

To separate ingestive factors involving palatability from post-ingestive factors responsible for forage intake being depressed by ensiling, silages were evaluated using sham-fed animals. Protocol for all experiments was to formulate low dry matter (DM) silages from a high DM lucerne silage reconstituted with either water, solutions containing constituents commonly found in silage, or extracts of low DM silage. Solutions of silage constituents were adjusted before reconstitution to a pH typical of silage. Tests were performed by offering silages one at a time once daily to oesophageal fistulated sheep, maintained on lucerne hay, but starved for 5 h prior to the test. Intake was measured over 30 min. Sheep were adapted to intermediate levels of each test ingredient(s) before experiments were done to evaluate effects of four to five levels of each ingredient using Latin-square designs. Animals were sham fed during both periods of adaptation and of testing ingredient levels. Mean of 30-min intakes for control silages was 573 g DM. Lactic and acetic acids added together, to levels of 53·2 and 35·4 g/kg, respectively, enhanced intake with a linear response due to level (P < 0·05). Acetic acid added by itself to 88·0 g/kg depressed intake with a linear response due to level (P < 0·05) in which 10 g/kg added acetic acid depressed 30-min intake by 13·5 g. Acetic and butyric acids added together to levels of 36·2 and 54·4 g/kg respectively, were without effect as was ammonia added to 3·8 g/kg as ammonia nitrogen (N). A mixture of free amino acids added to a level of 9·2 g amino-N per kg was without effect, but at a level of 13·8 g/kg, intake was depressed to proportionately 0·75 of the control. A mixture of two amines and gamma amino butyric acid added to a level of 4·6 g N per kg caused a quadratic response (P < 005) in which intermediate levels enhanced intake but the highest level was without effect. An extract from good-quality silage had no effect on intake and that from a poor-quality silage enhanced intake in a linear manner (P < 0·05). These data indicate that elevation of acetic acid in silage without increases in amounts of other constituents decreased intake of silage through an effect on palatability. This conclusion modifies interpretation on the significance of palatability, determined from studies of ingestive behaviour of ruminants, as a factor to explain reduced intake of sheep given silage.

1. Four roughages were given ad lib. to each of eight steers. The amount consumed and the apparent digestibility of the energy of each roughage were determined together with the weight gains of the steers.

2. The mean voluntary intake of dry matter was related to the mean apparent digestibility of the energy of the roughages in the same quantitative way for the steers as had been noted with sheep. Mean weight gains were proportional to the mean number of calories of energy apparently digested.

3. Significant differences between individuals occurred in their voluntary food intakes, and those animals which consumed most digested it least efficiently. The variation in intake from individual to individual expressed as a standard deviation was ±7·5% of the mean.

4. The quantitative similarity of sheep and cattle as far as the relationship between their voluntary consumption of food of different apparent digestibility is concerned, is contrasted with their dissimilarity with respect to fasting metabolism. It is suggested that sheep are likely to prove more efficient convertors of the energy of roughages to body gain than are cattle.

Further work is clearly necessary to explore the extent of these differences.

Insight into current scientific applications of Big Data in the precision dairy farming area may help us to understand the inflated expectations around Big Data. The objective of this invited review paper is to give that scientific background and determine whether Big Data has overcome the peak of inflated expectations. A conceptual model was created, and a literature search in Scopus resulted in 1442 scientific peer reviewed papers. After thorough screening on relevance and classification by the authors, 142 papers remained for further analysis. The area of precision dairy farming (with classes in the primary chain (dairy farm, feed, breed, health, food, retail, consumer) and levels for object of interest (animal, farm, network)), the Big Data-V area (with categories on Volume, Velocity, Variety and other V’s) and the data analytics area (with categories in analysis methods (supervised learning, unsupervised learning, semi-supervised classification, reinforcement learning) and data characteristics (time-series, streaming, sequence, graph, spatial, multimedia)) were analysed. The animal sublevel, with 83% of the papers, exceeds the farm sublevel and network sublevel. Within the animal sublevel, topics within the dairy farm level prevailed with 58% over the health level (33%). Within the Big Data category, the Volume category was most favoured with 59% of the papers, followed by 37% of papers that included the Variety category. None of the papers included the Velocity category. Supervised learning, representing 87% of the papers, exceeds unsupervised learning (12%). Within supervised learning, 64% of the papers dealt with classification issues and exceeds the regression methods (36%). Time-series were used in 61% of the papers and were mostly dealing with animal-based farm data. Multimedia data appeared in a greater number of recent papers. Based on these results, it can be concluded that Big Data is a relevant topic of research within the precision dairy farming area, but that the full potential of Big Data in this precision dairy farming area is not utilised yet. However, the present authors expect the full potential of Big Data, within the precision dairy farming area, will be reached when multiple Big Data characteristics (Volume, Variety and other V’s) and sources (animal, groups, farms and chain parts) are used simultaneously, adding value to operational and strategic decision.

Although stocking rate is a key management variable influencing the structure and composition of pastures, only few studies have simultaneously analysed the seasonal patterns of pasture use by cattle, and the adjustments the animals make to maintain intake of a high-quality diet over the grazing season. Therefore, over a 3-year study, we recorded diet selection, plot use and impact of heifers on sward structure and quality under three different stocking rates (0.6, 1.0 and 1.4 livestock units (LU) per ha) in a species-rich mountain pasture of central France. Measurements were made on three occasions between early June and the end of September each year. Overall, heifers selected for bites dominated by legumes or forbs, and against reproductive grass, whatever the stocking rate or season. Selection for tall mixed (P < 0.05), short mixed (P < 0.05) and short pure grass bites (P < 0.01) was more pronounced in plots grazed at the lowest stocking rate. Although heifers’ selection for short patches decreased at the end of the season (P < 0.001), they continued to graze previously grazed areas, thus exhibiting a typical ‘patch grazing’ pattern, with the animals that grazed at the lowest stocking rate tending to better maintain their selection for short patches in September (treatment × period: P = 0.078). Neither diet quality nor individual animal performance were affected by the different stocking rate treatments despite high variability in the quantity and quality of herbage offered and differences in diet selection. However, at the 1.4 LU per ha stocking rate, the quantity of forage available per animal at the end of the season, 0.79 t dry matter (DM) per ha of green leaves with the median of sward height at 4.6 cm, approached levels limiting cattle’s ability to compensate for the effects of increasing stocking rate. In plots grazed at 0.6 LU per ha, the total herbage biomass remained higher than 3 t DM per ha with more than 30% of plot area still covered by reproductive grass patches at the end of the grazing season, which in the medium term should affect the botanical composition of these pastures. Sward heterogeneity was high in plots grazed at 1.0 LU per ha, with sufficient herbage availability (1.1 t DM per ha of green leaves) to maintain animal performance, and more than 15% of plot area was kept at a reproductive stage at the end of the grazing season. Hence, it could represent the optimal balance to satisfy both livestock production and conservation management objectives.

The transferrins in Swedish cattle were studied with the starch gel method. A continuous tris buffer system was used. With sera from young calves each transferrin allele appeared to determine four fractions. Among some animals from Norway two seemed to have a transferrin type not earlier described for the European cattle breeds. The frequencies of the transferrin alleles found in a bull sample from the Swedish Red-and-White breed were TfA = 0·53, TfD = 0·18 and TfE = 0·29. Family data were in good agreement with the theory of inheritance. The transferrin types were used in parentage testing and a formula is given for the possibility of making exclusions. The value of the transferrin types in diagnosis of zygosity in cattle twins is shown. The transferrins seem to occur in bovine milk also.

Increasing the polyunsaturated fatty acid (PUFA) composition of milk is acknowledged to be of benefit to consumer health. Despite the high PUFA content of forages, milk fat contains only about 3% of PUFA and only about 0.5% of n-3 fatty acids. This is mainly due to intensive lipid metabolism in the rumen (lipolysis and biohydrogenation) and during conservation (lipolysis and oxidation) such as drying (hay) and ensiling (silage). In red clover, polyphenol oxidase (PPO) has been suggested to protect lipids against degradation, both in the silage as well as in the rumen, leading to a higher output of PUFA in ruminant products (meat and milk). PPO mediates the oxidation of phenols and diphenols to quinones, which will readily react with nucleophilic binding sites. Such binding sites can be found on proteins, resulting in the formation of protein-bound phenols. This review summarizes the different methods that have been used to assess PPO activity in red clover, and an overview on the current understanding of PPO activity and activation in red clover. Knowledge on these aspects is of major importance to fully harness PPO’s lipid-protecting role. Furthermore, we review the studies that evidence PPO-mediated lipid protection and discuss its possible importance in lab-scale silages and further in an in vitro rumen system. It is demonstrated that high (induction of) PPO activity can lead to lower lipolysis in the silage and lower biohydrogenation in the rumen. There are three hypotheses on its working mechanism: (i) protein-bound phenols could directly bind to enzymes (e.g. lipases) as such inhibiting them; (ii) binding of quinones in and between proteins embedded in a lipid membrane (e.g. in the chloroplast) could lead to encapsulation of the lipids; (iii) direct binding of quinones to nucleophilic sites in polar lipids also could lead to protection. There is no exclusive evidence on which mechanism is most important, although there are strong indications that only lipid encapsulation in protein–phenol complexes would lead to an effective protection of lipids against ruminal biohydrogenation. From several studies it has also become apparent that the degree of PPO activation could influence the mode and degree of protection. In conclusion, this review demonstrates that protein-bound phenols and encapsulation in protein–phenol complexes, induced by PPO-mediated diphenol oxidation, could be of interest when aiming to protect lipids against pre-ruminal and ruminal degradation.

Nutritional requirements of the Iberian pig, a slow-growing, obese porcine breed, are not well defined and seem to differ from those of conventional or high-performing pigs. The effects of the dietary protein content and the feeding level on the utilisation of metabolisable energy (ME) and the rates of gain, protein, and fat deposition were studied with 81 Iberian castrates growing from 50 to 100 kg body weight (BW) by using the comparative slaughter technique. The animals were fed 4 diets providing 145, 120, 95, and 70 g ideal crude protein (CP) per kg dry matter (DM), and containing 13.94, 14.29, 14.56, and 14.83 MJ ME per kg DM, respectively. Three levels of feeding were evaluated: 0.60, 0.80, and 0.95 × ad libitum intake. Growth rate increased (linear and quadratic, P < 0.001) as the dietary ideal CP content decreased. It also increased with the feeding level (linear, P < 0.001; quadratic, P < 0.05). Gain:feed and gain:ME intake improved by decreasing the ideal CP content in the diet (linear, P < 0.001 and P < 0.05, respectively; quadratic P < 0.001 for both variables). Increasing the feeding level improved linearly gain:feed and gain:ME intake ( P < 0.001). Protein deposition (PD):ME intake ranged between 1.23 and 1.44 g/MJ, and it showed a tendency to reach the maximum value when the diet providing 95 g ideal CP per kg DM was fed (quadratic, P = 0.078). When this diet was offered at 0.95 × ad libitum, PD reached a maximum value of 71 g/day. This dietary treatment resulted in average values for average daily gain and retained energy (RE) of 854 g/day and 21.4 MJ/day, respectively. The average rate of gain was 19.93 g/MJ increase in ME intake, equivalent to an energy cost of 50.2 kJ ME per g gain, irrespective of the dietary ideal CP content. Also, the overall marginal efficiency of protein deposition (ΔPD:ΔME; g/MJ) was 1.34. Increasing the feeding level led to increases in PD (linear, P <  0.001) and RE (linear, P <  0.001; quadratic, P <  0.01) irrespective of the dietary ideal CP concentrations. Between 50 and 100 kg BW, the chemical composition of 1 kg gain averaged 78, 592, 28.7, and 284 g for CP, fat, ash, and water respectively. The net efficiency of use of ME for growth ( kg) and the maintenance energy requirements were 0.606 and 396 kJ/kg BW 0.75 per day, respectively. The results support earlier findings that the genotype has marked effects on protein and energy metabolism of growing pigs and underline important compositional differences of the Iberian pig compared with conventional or modern porcine genotypes.

Near infrared reflectance spectroscopy (NIRS) was used to study the reflectance properties of intact and minced lamb muscles in two presentations to the instrument to predict their chemical composition. A total of 306 muscles were examined from 51 lambs, consisting of the following muscles: longissimus dorsi, supraspinatus, infraspinatus, semimembranosus, semitendinosus and rectus femoris. Modified partial least squares (MPLS) regression models of chemical variables yielded R2 and standard error of cross-validation (SECV) of 0·76 (SECV: 10·4), 0·83 (SECV: 5·5) and 0·73 (SECV: 4·7) for moisture, crude protein and intramuscular fat in the minced samples expressed as g/kg on a fresh-weight basis, respectively. Calibrations for intact samples had lower R2 and higher standard error of cross validation (SECV) compared with the minced samples.

A theoretical study is reported of the way in which additive genetic improvement, made in a nucleus population, is passed to successive levels in a three-tier multiplication system. The rate at which progress accumulates at each level is approximately equal. The extent to which each tier is genetically behind the previous one has been termed the ‘improvement lag’. These lags can be considerable; their actual size is determined by the annual rate of progress in the nucleus, the age structure in the lower tiers, and by the origins and degree of selection achieved in the animals used as parents in these tiers. Only improvements generated in the top tier are cumulative. The scope for reducing the improvement lag is discussed within the context of livestock production in Britain.