An evolutionary algorithm was applied to a mechanistic model of the mammary gland to find the parameter values that minimised the difference between predicted and actual lactation curves of milk yields in New Zealand Jersey cattle managed at different feeding levels. The effect of feeding level, genetic merit, body condition score at parturition and age on total lactation yields of milk, fat and protein, days in milk, live weight and evolutionary algorithm derived mammary gland parameters was then determined using a multiple regression model. The mechanistic model of the mammary gland was able to fit lactation curves that corresponded to actual lactation curves with a high degree of accuracy. The senescence rate of quiescent (inactive) alveoli was highest at the very low feeding level. The active alveoli population at peak lactation was highest at very low feeding levels, but lower nutritional status at this feeding level prevented high milk yields from being achieved. Genetic merit had a significant linear effect on the active alveoli population at peak and mid to late lactation, with higher values in animals, which had higher breeding values for milk yields. A type of genetic merit × feeding level scaling effect was observed for total yields of milk and fat, and total number of alveoli produced from conception until the end of lactation with the benefits of increases in genetic merit being greater at high feeding levels. A genetic merit × age scaling effect was observed for total lactation protein yields. Initial rates of differentiation of progenitor cells declined with age. Production levels of alveoli from conception to the end of lactation were lowest in 5- to 8-year-old animals; however, in these older animals, quiescent alveoli were reactivated more frequently. The active alveoli population at peak lactation and rates of active alveoli proceeding to quiescence were highest in animals of intermediate body condition scores of 4.0 to 5.0. The results illustrate the potential uses of a mechanistic model of the mammary gland to fit a lactation curve and to quantify the effects of feeding level, genetic merit, body condition score, and age on mammary gland dynamics throughout lactation.

A total of 19 376 test day (TD) milk yield records from the first three lactations of 1618 cows daughters of 162 sires were used to estimate genetic and phenotypic parameters and determine the relationship between daily milk yield and lactation milk yield in the Sahiwal cattle in Kenya. Variance components were estimated using animal models based on a derivative free restricted maximum likelihood procedure. Variance components were estimated using various univariate and multi-trait fixed regression test day models (TDM) that defined contemporary groups either based on the year-season of calving (YSCV) or on the year-season of TD milk sampling (YSTD). Variance components were influenced by CG which resulted in differences in heritability and repeatability estimates between TDM. Models considering YSTD resulted in higher additive genetic variances and lower residual variances compared with models in which YSCV was considered. Heritability estimates for daily yield ranged from 0.28 to 0.46, 0.38 to 0.52 and 0.33 to 0.52 in the first, second and third lactation, respectively. In the first and second lactation, the heritability estimates were highest between TD 2 and TD 4. Genetic correlations among daily milk yields ranged from 0.41 to 0.93, 0.50 to 0.83 and 0.43 to 86 in the first, second and third lactation, respectively. The phenotypic correlations were correspondingly lower. Genetic correlations were different from unit when fitting multi-trait TDM. Therefore, a multiple trait model would be more ideal in determining the genetic merit of dairy sires and bulls based on daily yield records. Genetic and phenotypic correlations between daily yield and lactation yields were high and positive. Genetic correlations ranged from 0.84 to 0.99, 0.94 to 1.00 and 0.94 to 0.97 in the first, second and third lactations, respectively. The corresponding phenotypic correlation estimates ranged from 0.50 to 0.85, 0.50 to 0.83 and 0.53 to 0.87. The high genetic correlation between daily yield and lactation yield imply that both traits are influenced by similar genes. Therefore daily yields records could be used in genetic evaluation in the Sahiwal cattle breeding programme.

Economic weights have been estimated in two breeds (Latxa and Manchega) using economic and technical data collected in 41 Latxa and 12 Manchega dairy sheep flocks. The traits considered were fertility (lambing per year), prolificacy (number of lambs), milk yield (litres) and longevity (as productive life, in years). A linear function was used, relating these traits to the different costs in the flock. The variable costs involved in the profit function were feed and labour. From this function, economic weights were obtained. Labour is considered in the Latxa breed to be a constraint. Moreover, farm profits are unusually high, which probably means that some costs were not included according to the economic theory. For that reason, a rescaling procedure was applied constraining total labour time at the farm. Genetic gains were estimated with the resulting economic weights to test if they give any practical difference. Milk yield only as selection criterion was also considered. The medians of the estimated economic weights for fertility, prolificacy, milk yield and longevity were 138.60 € per lambing, 40.00 € per lamb, 1.18 € per l, 1.66 € per year, and 137.66 € per lambing, 34.17 € per lamb, 0.73 € per l, 2.16 € per year under the linear approach in the Latxa and Manchega breeds respectively. Most differences between breeds can be related to differences in production systems. As for the genetic gains, they were very similar for all economic weights, except when only milk yield was considered, where a correlated decrease in fertility led to a strong decrease in profit. It is concluded that the estimates are robust for practical purposes and that breeding programmes should consider inclusion of fertility. More research is needed to include other traits such as somatic cell score, milk composition and udder traits.

The economic weights for somatic cell score (SCS) have been calculated using profit functions. Economic data were collected in the Latxa breed. Three aspects have been considered: bulk tank milk payment, veterinary treatments due to high SCS, and culling. All of them are non-linear profit functions. Milk payment is based on the sum of the log-normal distributions of somatic cell count, and veterinary treatments on the probability of subclinical mastitis, which is inferred when individual SCS surpass some threshold. Both functions lead to non-standard distributions. The derivatives of the profit function were computed numerically. Culling was computed by assuming that a conceptual trait culled by mastitis (CBM) is genetically correlated to SCS. The economic weight considers the increase in the breeding value of CBM correlated to an increase in the breeding value of SCS, assuming genetic correlations ranging from 0 to 0.9. The relevance of the economic weights for selection purposes was checked by the estimation of genetic gains for milk yield and SCS under several scenarios of genetic parameters and economic weights. The overall economic weights for SCS range from − 2.6 to − 9.5 € per point of SCS, with an average of − 4 € per point of SCS, depending on the expected average SCS of the flock. The economic weight is higher around the thresholds for payment policies. Economic weights did not change greatly with other assumptions. The estimated genetic gains with economic weights of 0.83 € per l of milk yield and − 4 € per point of SCS, assuming a genetic correlation of − 0.30, were 3.85 l and − 0.031 SCS per year, with an associated increase in profit of 3.32 €. This represents a very small increase in profit (about 1%) relative to selecting only for milk yield. Other situations (increased economic weights, different genetic correlations) produced similar genetic gains and changes in profit. A desired-gains index reduced the increase in profit by 3%, although it could be greater depending on the genetic parameters. It is concluded that the inclusion of SCS in dairy sheep breeding programs is of low economic relevance and recommended only if recording is inexpensive or for animal welfare concerns.

The objectives of this study were to determine true phosphorus (P) digestibility, degradability of phytate-P complex and the endogenous P outputs associated with brown rice feeding in weanling pigs by using the simple linear regression analysis technique. Six barrows with an average initial body weight of 12.5 kg were fitted with a T-cannula and fed six diets according to a 6 × 6 Latin-square design. Six maize starch-based diets, containing six levels of P at 0.80, 1.36, 1.93, 2.49, 3.04, and 3.61 g/kg per kg dry-matter (DM) intake (DMI), were formulated with brown rice. Each experimental period lasted 10 days. After a 7-day adaptation, all faecal samples were collected on days 8 and 9. Ileal digesta samples were collected for a total of 24 h on day 10. The apparent ileal and faecal P digestibility values of brown rice were affected ( P < 0.01) by the P contents in the assay diets. The apparent ileal and faecal P digestibility values increased from − 48.0 to 36.7% and from − 35.6 to 40.0%, respectively, as P content increased from 0.80 to 3.61 g/kg DMI. Linear relationships ( P < 0.05), expressed as g/kg DMI, between the apparent ileal and faecal digestible P and dietary levels of P, suggested that true P digestibility and the endogenous P outputs associated with brown rice feeding could be determined by using the simple regression analysis technique. There were no differences ( P>0.05) in true P digestibility values (57.7 ± 5.4 v. 58.2 ± 5.9%), phytate P degradability (76.4 ± 6.7 v. 79.0 ± 4.4%) and the endogenous P outputs (0.812 ± 0..096 v. 0.725 ± 0.083 g/kg DMI) between the ileal and the faecal levels. The endogenous faecal P output represented 14 and 25% of the National Research Council (1998) recommended daily total and available P requirements in the weanling pig, respectively. About 58% of the total P in brown rice could be digested and absorbed by the weanling pig. Our results suggest that the large intestine of the weanling pigs does not play a significant role in the digestion of P in brown rice. Diet formulation on the basis of total or apparent P digestibility with brown rice may lead to P overfeeding and excessive P excretion in pigs.

A study to compare two feeding systems, stall feeding (SF) and grazing plus supplementation (GR) was carried out, based on intake, performance and rumen fermentation characteristics of lambs. While SF animals received ad libitum complete feed blocks (CFB), GR animals were allowed grazing for 8 h on a pasture and supplemented with concentrate mixture at 250 g per head per day. Intake in grazing animals was determined using chromium III oxide as internal marker. Intake of dry matter (DM), crude protein (CP) and organic matter (OM) were higher ( P < 0.01) in SF than in GR animals. Similarly, digestibility of OM, CP and energy were higher ( P < 0.01) in SF animals. Average daily gain in SF animals (101 g) was significantly ( P < 0.01) higher than in GR animals (78 g) but total wool yield was similar for the two groups (856 g, SF; 782 g, GR). The pH of the rumen content, concentration of total volatile fatty acids and total activities of carboxymethyl cellulase, xylanase and esterase in the rumen liquor were similar. The concentrations (mg/dl) of total nitrogen (125, SF; 63, GR) and NH3-nitrogen (42, SF; 31, GR) were higher in SF animals than that of GR animals. A significantly higher activity ( P < 0.05) of microcrystalline cellulase (24.5 v. 7.7 units) and lower activity ( P < 0.05) of protease (309 v. 525 units), was observed in the rumen of SF animals than in GR animals. SF animals could therefore harness more energy through degradation of plant cell walls thus reducing breakdown of plant proteins as gluconeogenic source. The SF system of feeding where CFB was offered to sheep appeared superior to GR in terms of intake, nutrient utilisation and animal performance. Therefore the SF feeding system where CFB are offered to animals can be advocated as an alternative to grazing and supplementation feeding strategy for sheep production, especially where the pastures are highly eroded and need resting for regeneration or curing. The CFB feeding can also be adopted under adverse conditions like drought and famine, a common phenomenon in arid and semiarid conditions.

This work was conducted to evaluate the effect of tannins, contained in a by-product derived from olive oil extraction (two-stage olive cake), on nutrient digestibility, nitrogen (N) losses and liver and kidney functions in goats and wethers. Six Segureña wethers and six Granadina goats were fed three experimental diets: alfalfa hay (AH); alfalfa hay and a concentrate (formulated with two-stage olive cake, barley and a mineral-vitamin mixture) without (AHCO) or with polyethylene glycol (PEG) addition (AHCOP). The inclusion of two-stage olive cake increased condensed tannins content of the diet and led to a decrease ( P < 0.001) in dry matter, organic matter, neutral-detergent fibre, acid-detergent fibre and crude protein (CP) digestibility. PEG supply increased ( P < 0.001) CP digestibility and N losses in urine and faeces only in wethers. Concentrations of creatinine and alkaline phosphatase activity, measured in the serum of animals, were not modified either by olive cake inclusion or by PEG supply. Results from this work indicate a higher sensitivity of sheep to diets containing condensed tannins, compared with goats, and reveal no toxic effect of tannins from two-stage olive cake at the concentration used in the experimental diets.

The milk production of dairy goats under various regimes of mother-young contact from day 4 post partum were studied during the first 2 months of lactation, together with the prolactin (PRL) and growth hormone (GH) responses to udder stimulation. In the control group, 13 goats and their kids were left in permanent contact and did not undergo milking. In two additional groups, goats were machine milked once a day in the morning (at 0800 h) and kids were allowed 10 hours (from 1000 to 2000 h; 10H group, n = 11) or 5 h (from 1000 to 2000 h; 5H group, n = 11) of mother-young interaction per day. In the last group (MO, n = 10), mothers were permanently separated from their kids on day 4 post partum and milked once a day. Milk production during a 24-h period at 37 days post partum performed by controlled nursing and weighing of the kids (groups with kids) or by two machine milking 12 h apart (milking only group) revealed a higher production in the three groups with some mother-young contact than in the MO group. Total milk collected by milking over the 2 months of the study did not differ between the three groups that underwent milking. Kid weights at 2 months were 3.4 to 4.8 kg. lighter in the groups that underwent milking than in the control group. Hormonal profiles were significantly affected by restricted mother-young contact, with highest pre-stimulation concentrations of PRL and GH in the 5H group. Restricting mother-young contact from the first week postpartum can permit an early collection of milk without major effects on kid growth, when compared with one daily milking in goats totally separated from their young.

In vitro gas production kinetics of six different substrates, pectin (PEC), xylan (XYL), starch (STA), cellulose (CEL), commercial compound feed (FEED; 201 g crude protein per kg, 155 g crude fibre per kg, 334 g neutral-detergent fibre (NDF) per kg and 190 g acid-detergent fibre (ADF) per kg) and an NDF prepared from commercial compound feed (NDFFEED) were determined using the caecum contents of weaned rabbits (36 days of age) and of rabbits at slaughter age (78 days of age) as inoculums. The cumulated gas production over 96 h of incubation was modelled with Gompertz model, and the kinetic parameters compared. The total potential gas production (parameter ‘B’ of the Gompertz model) was not affected (P>0.05) by the inoculum source, except with STA, where rabbits at slaughter weight had significantly higher total potential fermentability (314 ml/g dry matter (DM)) than those at weaning age (189 ml/g DM). Intensities of fermentation (maximum fermentation rate; MFR) of PEC (32.2 ml/h) and XYL (24.4 ml/h) were significantly greater in rabbits at weaning, while that of STA (45 ml/h) was significantly lower than at slaughter age (23.0, 14.3 and 14.0 ml/h for PEC, XYL and STA, respectively). The MFRs of CEL and NDFFEED were very similar between inoculum sources. In the first 10 h of fermentation which correspond to the normal retention time of the substrates in the caecum, the highest amount of gas was produced from PEC, followed by FEED and XYL. These substrates had a time of maximum fermentation rate (TMFR) at both rabbit ages short enough (8.0 and 9.5 h for PEC, 9.5 and 6.6 h for FEED, 13.7 and 14.2 h for XYL at weaning and at slaughter age, respectively) to be almost completely fermented in vivo.

It is well established that dietary protein supply can influence the peri-parturient breakdown of immunity to nematode parasites but there is no information on the importance of exposure to nematode larvae during pregnancy for this response. We investigated this by exposing housed pregnant sheep, scanned as carrying two lambs, to a vaccinating infection with a trickle mixed infection of Teladorsagia circumcincta and Trichostrongylus colubriformis larvae (L3) or to no infection during weeks − 9 to − 4 relative to parturition. At the beginning of week − 3 all sheep were treated with anthelmintic to remove any vaccinating worm burden and from week − 2 to week +6 received a trickle challenge infection with the same nematodes. Within each vaccinating treatment there were two nutritional treatments (no. = 20 per subgroup) designed to provide 1.5 or 1.0 and 1.3 or 0.8 of metabolisable protein (MP) requirement during pregnancy and lactation, respectively. Five ewes were necropsied during weeks +1 and +3 to measure worm burdens and mucosal inflammatory cells and the remainder maintained until week +6. Serum levels of total, IgA and IgE antibodies against L3 antigen of each nematode were measured.

Scanning errors and lamb losses resulted in some ewes carrying and/or rearing only one lamb. Numbers of lambs reared was therefore introduced as a treatment effect. Vaccinating infection delayed the peri-parturient rise in faecal egg count (FEC) by an average of 2 weeks but its effect on FEC during the first 6 weeks of lactation was smaller and less persistent than that of dietary MP supply and single- v. twin-suckling.

Populations of both nematodes were lower in association with high MP supply, vaccination and single suckling. These changes were associated with increases in numbers of mucosal mast cells (MMC) as a result of both increased MP supply and vaccination. Evidence for a more rapid return of host ability to limit populations of the abdominal nematode T. circumcincta than of the intestinal nematode T. colubriformis was associated with fewer eosinophils and more globule leucocytes (GL) in abomasal than in intestinal tissue.

None of the serum antibody isotypes was affected by dietary protein supply. Total and IgA antibodies were maintained by a current larval (vaccinating) intake. IgA titres, however, increased progressively during pregnancy, especially in twin-bearing ewes. IgE titres appeared to be sensitive primarily to the reproductive cycle itself, peaking around parturition.

This work supports the conclusion that availability of MP supply influences the recruitment and activity of cells of the immune armoury of the gastro-intestinal tract to nematode parasites. The precise outcome may differ with site and/or nematode species.

The influence of body weight (BW) at slaughter and genotype on adipocyte size and number in the omental (OM), perirenal (PR), subcutaneous (SC) and intermuscular (IM) adipose tissues was studied in 168 bulls of Spain's local Asturiana, Avileña, Morucha, Parda Alpina, Pirenaica, Retinta, and Rubia Gallega cattle breeds. The young bulls were slaughtered at two BWs, 320 and 540 kg. The results obtained showed the higher amounts of lipids that accumulated between 320 and 540 kg BW (P < 0.001) to be ascribable primarily to adipose cell hypertrophy, i.e. larger adipocyte size, in the OM and PR depots (P < 0.001). In addition to hypertrophy, there was also an increase (P < 0.001) in the number of adipose cells, i.e. hyperplasia, in the SC and IM adipose depots. Significant differences were observed when comparing the different genotypes, with the Morucha, Retinta and Avileña breeds having the highest amount of adipose tissue and the largest adipocytes. The Asturiana and Rubia Gallega breeds had the lowest amount of adipose tissue and the smallest adipocytes. The Pirenaica and Parda Alpina breeds had intermediate values in between the two groups identified above. In short, the results were indicative of different lipid deposition patterns in the different breeds depending on the individual growth and maturation rates in each. Similar findings were made when comparing the different adipose tissue depots, with adipocyte hypertrophy being the main factor responsible for lipid accumulation in the OM and PR depots, as opposed to adipocyte hyperplasia in the SC and IM depots.

Data from 27 feeding trials conducted on growing pigs from different research institutes across India were subjected to mixed model regression analysis to derive requirements of digestible energy (DE), crude protein (CP) and essential amino acids for maintenance and body weight gains. The ranges of maintenance requirements were determined to be: DE 516 to 702 kJ/kg M0.75, CP 6.98 to 11.62, lysine 0.431 to 0.664, methionine 0.265 to 0.458, methionine + cystine 0.327 to 0.466, cystine 0.055 to 0.184, threonine 0.205 to 0.511, arginine 0.377 to 1.21, isoleucine 0.241 to 0.775, leucine 0.604 to 1.54, phenylalanine + tyrosine 0.496 to 1.33, tryptophan 0.078 to 0.213, and valine 0.330 to 0.892 g/kg M0.75, respectively for different body weight ranges. The corresponding requirements for 1 g gain in body weight were: DE 28.6 to 38.6 kJ, CP 0.27 to 0.44 g, lysine 0.0071 to 0.0126 g, methionine 0.0047 to 0.0133 g, methionine + cystine 0.0151 to 0.0261 g, cystine 0.0043 to 0.0094 g, threonine 0.0052 to 0.0165 g, arginine 0.0045 to 0.0301 g, isoleucine 0.0023 to 0.0198 g, leucine 0.0150 to 0.0447 g, phenylalanine + tyrosine 0.0091 to 0.0382 g, tryptophan 0.0005 to 0.0044 g, and valine 0.0061 to 0.0222 g. Regression equations had high R2 values (ranging from 0.50 to 0.99 for different estimates), low coefficients of variation, low variance of error estimates and the coefficients were highly significant (P < 0.001). Regressed values were used to develop feeding standards. As the new standards derived in the present study are based on a thorough analysis of a larger database than previous Indian standards, the new feeding standard seems to be more appropriate for India and other tropical countries.

Twenty-four low dry matter (DM) silages differing in fermentation quality were harvested at the same time from a crop that consisted mainly of timothy (Phleum pratense), and meadow fescue (Festuca pratensis). The silage samples were analysed by gas chromatography (GC) – mass spectrometry and gas chromatography – flame ionisation detection in order to determine and quantify volatiles present in silage. The voluntary intake of the 24 silages had been measured in a previous feeding trial with growing steers of Norwegian Red. Thirteen esters, five aldehydes, three alcohols, and one sulphide were identified and quantified. A total of 51 variables describing the chemical composition of the silages were included in a partial least-squares regression, and the relationship of silage fermentation quality to voluntary intake was elucidated. The importance of variables describing silage fermentation quality in relation to intake was judged from a best combination procedure, jack-knifing, and empirical correlations of the variables to intake. The GC-analysed compounds were mainly present in poorly fermented silages. However, compared with other explanatory chemical variables none of these compounds was of importance for the voluntary intake as evaluated by partial least-squares regression. A validated variance of 71% in silage DM intake was explained with the selected variables: total acids (TA), total volatile fatty acids (TVFA), lactic acid/total acid ratio and propionic acid. In this study extent (by the variable TA) and type of silage fermentation (by TVFA) influenced intake. Further, it is suggested that by restricting the fermentation in low DM grass silages the potential intake of silage DM is maximised.

Reproductive efficiency in the dairy herd is the most important factor for its economic success and a major concern for dairy farmers when using artificial insemination (AI) or natural service (NS). Our objectives were to estimate, compare and analyse the costs associated with breeding cattle by do-it-yourself (DIY) AI and NS and identify the factors that influence them, under typical dairy farming conditions in Greece. A simulation study was designed based on data from 120 dairy cattle farms that differed in size (range 40 to 285 cows) and milk production level (4000 to 9300 kg per cow per year). Different scenarios were employed to estimate costs associated directly with AI and NS as well as potentially extended calving intervals (ECI) due to AI. Results showed that bull maintenance costs for NS were €1440 to €1670 per year ($1,820 to $2,111). Direct AI costs were higher than those for NS for farms with more than 30 cows and ECI constituted a considerable additional burden. In fact, amongst the factors that affected the amount of milk needed to cover total extra AI costs, number of days open was the dominant one. Semen, feed and heifer prices had a very small effect. When, hypothetically, use of NS bulls results in a calving interval of 12 months, AI daughters with a calving interval of 13.5 months have to produce about 705 kg of additional milk in order to cover the extra cost. Their actual milk production, however, exceeds this limit by more than 25%. When real calving intervals are considered (13.0 v. 13.7 months for NS and AI, respectively) AI daughters turn out to produce more than twice the additional amount of milk needed. It was concluded that even under less than average management conditions, AI is more profitable than the best NS scenario. The efficient communication of this message should be a primary concern of the AI industry.

The objective of the present study was to investigate the effects of fermented oyster mushroom (Pleurotus ostreats) by-production (FOMP) supplementation on the growth performance, blood parameters, carcass traits and meat quality in finishing Berkshire pigs. FOMP was made by mixing oyster mushroom by-production with rice bran and barley bran and this mixture was fermented for 60 days. The experimental diets were 0, 3, 5 and 7% of FOMP added to C, T1, T2 and T3 in the basis diet for 7 weeks. Average daily gain (kg/day) was higher in C and T1 than in T2 and T3 ( P < 0.05). Average daily feed intake (kg/day) and feed conversion increased by the addition of FOMP ( P < 0.05). Total cholesterol and high-density lipoprotein cholesterol were higher in T3 than other treatments ( P < 0.05). Carcass weight (kg) was higher in C and T1 than in T2 and T3 ( P < 0.05). Dressing (%) was higher in C than in T3 ( P < 0.05). Crude protein was lower in T3 than in other treatments ( P < 0.05). Crude fat was higher in T2 and T3 than in C ( P < 0.05). pH24 was higher in C than in other treatments ( P < 0.05). Cooking loss (%) was higher in T1 than T2 ( P < 0.05). Water-holding capacity (%) was higher in C than in T1 ( P < 0.05). In meat colour, CIE a* was lower by the addition of FOMP ( P < 0.05). CIE b* was higher in C than in other treatments ( P < 0.05). In backfat colour, CIE L* was lower in T3 than other treatments ( P < 0.05). CIE b* was lower by addition of FOMP ( P < 0.05). Palmitoleic and oleic acid were higher in T3 than in other treatments ( P < 0.05). Linoleic and arachidonic acids were higher in T2 than in other treatments ( P < 0.05). The results indicate that 3% of FOMP affected the growth performance, carcass traits, meat quality and fatty acid in contrast to addition of 5% of FOMP for Berkshire pigs during the finishing period.

Over the last two or three decades meat and especially liver have been looked upon as unhealthy food with high fat content and carcinogenic potential. In addition, its content of highly valuable micronutrients has mostly been ignored. As a result, the mean uptake and serum levels of several micronutrients in the population are below the recommended levels. In the meantime, the contamination of liver with heavy metals and other contaminants has fallen far below the allowed thresholds and sometimes even below the detection limit while its content of micronutrients like iron, folate, selenium or zinc are still high. As a further advantage, the bioavailability of many micronutrients often is better from meat and liver then from plant sources. Considering these advantages and the low content of contaminants in meat and liver leads us to propose that meat – including liver – should be a regular part of a mixed and balanced healthy diet along with vegetables and fruits as the major components to ensure an optimal supply of micronutrients.