A series of 24-h video studies on four commercial Danish pig herds investigated the behaviour of pregnant sows kept in dynamic groups (72 to 200 sows) with electronic sow feeding (ESF). The herds mainly differed with respect to provision of a layer of unchopped straw as bedding material, the frequency of introduction/removal of animals, space allowance in the lying area, group size and number of feeding stations, and starting times for the feeding cycle. All herds had one feeding cycle per 24 h. Six 24-h video recordings in the most settled period with respect to rank relationships (2 to 12 days after the last introduction) were collected from each herd and analysed according to activity and aggressive interactions. In two of the four herds recordings were collected in two separate periods with different starting times for the feeding cycle. In all herds peaks of activity in the morning and in the afternoon were evident. Furthermore, the diurnal variation was overlaid by an increase in activity at the start of the feeding cycle. The activity and aggression in the feeding area as well as the duration per sow of the period with high feeder occupation were lowest in herds where a layer of straw bedding was provided. Changing feeding start from day time to night time was accompanied by a reduced feeder occupation in the period following start of the feeding cycle. However, in herd 1 (characterized by no litter, high stocking density and high frequency of grouping) the level of aggression was reduced, whereas it was increased in herd 2 (characterized by straw in lying area, low stocking density, low frequency of regrouping). Number of regroupings and space allowance apparently had no obvious effects on the average frequency of aggression or the aggression per sow at risk in periods between introduction of new animals, but space allowance may have improved social function by weakening the association between activity and aggression. Due to the small number of herds included the present results were descriptive rather than conclusive. However, the study supports the suggestions that provision of unchopped straw as bedding material and starting the feeding cycle in the evening for overnight feeding may improve behaviour in dynamic group housing systems with ESF. However, the benefits of starting the feeding cycle in the evening may depend on low disturbance in daytime from other management procedures.

A total of 16 multiparous (range 2nd to 9th parity) Camborough sows were housed over parturition and during lactation in a group farrowing system. Two replicates of four sows were studied in the large pen (L) and two further replicates studied in the small pen (S) configuration, providing 13•4 m2 and 8•6 m2 per sow, respectively. A lactation diet providing 14 MJ/kg digestible energy (DE) and 180 g/kg crude protein was supplied ad libitum via a sow-operated feeder, adapted to facilitate the calculation of individual food intakes. The influence of environmental, physical, and production factors upon food intakes and feeding strategies was investigated. Daily food intakes of 7•69 (s.e. 0•31) kg and 7•72 (s.e. 0•35) kg were achieved during lactation by sows in the L and S pen configurations, respectively, accomplished by sows taking a series of small meals throughout the day. Sows in the S pen area made fewer visits to the feeder and spent less time per day feeding than sows in the L pen area. However, more food was consumed per visit by the S sows, resulting in similar daily food intakes in both treatment groups. There was a depression in lactation food intakes of sows housed at a mean daily ambient temperature of 17•5ºC compared with the other sow groups. The majority of sows consumed energy well in excess of their predicted requirements during lactation, whilst one sow in the L and two in the S pen areas had intakes within ±3•4 MJ DE of predictions. Only two of the L sows had food intakes that produced an energy deficit. In the L pen area, two distinct peaks of feeding activity occurred from 09:00 to 13:00 h and from 15:00 to 23:00 h that accounted for 0•77 of the total feeding time. In contrast, in the S pen configuration, one prolonged period of feeding occurred from 09:00 to 22:00 h accounting for 0•88 of total feeding time. The results show that S sows adapted their feeding patterns to maintain similar daily intakes to those of L sows, thus demonstrating that an ad libitum food supply enabled sows to obtain individual nutritional requirements in a communal farrowing system.

There is some evidence to show that loose housing during gestation has a negative influence on the welfare of sows subsequently in farrowing crates. However, little is known about the effects of the gestation housing on the initial responses of gilts to the farrowing crate or of the effects on gilt welfare throughout lactation. The objective of this experiment was to evaluate three gestation housing systems (1) stalls (ST); (2) loose-bedded (LB) and (3) loose-unbedded (LU) pens for their effect on behaviour, heart rate and skin lesion scores of gilts in farrowing crates. During the 1st h in the farrowing crate, LB gilts were more active, while ST gilts were more vocal. Although heart rates during the 1st h did not differ significantly between treatments, LB and LU gilts had significantly higher mean heart rates during the first 5 min in the crate, compared with 35 min later. Posture changes during the first 24 h did not differ between treatments. However, there was a significant reduction in the number of posture changes made by ST gilts but not LB or LU gilts by day 8. Increases in the skin lesion score of gilts in all three treatments were observed after 24 h in the crate, further increases were observed post farrowing in both loose treatments. Although no significant differences in the skin lesion score were observed during lactation, LB gilts were weaned with lower lesion scores than LU or ST gilts. Gilts from both loose treatments experienced greater distress at first introduction to the farrowing crate. However, the change in environment also had an adverse affect on the welfare of ST gilts. Skin damage and continuing discomfort of the loose-housed gilts post farrowing suggests that they experienced more stress at parturition. Bedding during gestation had a beneficial effect on skin health in the farrowing crate that persisted until weaning.

Six multiparous Holstein-Friesian cows were offered a total mixed ration based on maize silage in a repeated measure design to evaluate the partition of gross energy (GE) during early to mid lactation. Four measurements were made at 6-week intervals with energy and nitrogen balances carried out in open-circuit respiration chambers over 6 days during lactation weeks 6, 12, 18 and 24. The intakes of total diet dry matter (DM) corrected for volatile losses (VCDM), organic matter (OM) and GE declined significantly (P < 0•01) as lactation progressed, although apparent digestibility of these fractions was not altered, resulting in a significant (P < 0•01) decline in digestible nutrient intake at each stage of lactation. Methane and urine energy losses were not significantly affected, resulting in significantly (P < 0·001) higher amounts of digestible energy (DE) partitioned to methane and urine as lactation progressed with associated significant reductions in metabolizable energy (ME) intake (MEI) (P < 0·01) and ME as a proportion of DE (P < 0·001) and GE (q) (P < 0·05). With advancing lactation there was a significant (P < 0·001) increase in the amount of ME partitioned to heat (HP/MEI), but no significant change in the amount partitioned to milk and tissue. Individual values for diet metabolizability (ME/GE) at actual (production) levels (qa) (mean 0·625 MJ/MJ) were corrected to an equivalent value at maintenance (qmc) (mean 0·666 MJ/MJ). The overall ME intakes (MJ/day) were: ad libitum, 246, corrected for level of feeding effect, 263, with a predicted ME requirement according to AFRC (1993) (MER93) of 242. Substitution of the calculated qmc into the predictive equations (AFRC, 1993) resulted in a mean maintenance requirement of 57·6 MJ/day (0·464 MJ/kg M0·75/day) whilst the mean value derived from the linear model describing the experimental data was 82·5 MJ/day (0·664 MJ/kg M0·75/day). The mean efficiencies of utilization of ME for milk production derived from AFRC (1993) and the linear regression model were 0·653 MJ/MJ and 0·625 MJ/MJ respectively.

Estimates of variance components for five egg traits on 26265 laying hens were obtained by restricted maximum likelihood (REML) using several models. In the DOMFS model, the effects included hatch group, additive genetic, full-sib, parental dominance and inbreeding depression. In the DOM model, the full-sib effect was eliminated. In the FS model, the parental dominance effect was eliminated. In the ADD model, both the full-sib and the dominance effects were eliminated. In the DOMFS model, the estimates of the full-sib variance were generally higher for egg production traits and lower for egg characteristics than those of the parental dominance variance. However, this model has partially failed in separating these two components. When the full-sib effect was removed from the model, almost all of its estimated variance moved to the estimated parental dominance variance. When the parental dominance effect was removed from the model, almost all of its estimated variance moved to the estimated full-sib variance. The estimates obtained with REML and the DOM model were compared with those obtained by method R and tilde-hat methodologies. The d2 (ratio of dominance variance to total variance) differed by up to 86% for method R and up to 225% for tilde-hat. The h2 differed by up to 26 and 28%, respectively. For data sets that are too large to be analysed with REML, method R is a feasible alternative. A model for estimation of dominance variance should also include the full-sib or a similar effect, provided the data set is large. Similarly, to analyse egg production traits, the model should include at least the full-sib effect.

This study provides estimates of genetic parameters for various diseases, fertility and 305-day milk production traits in dairy cattle using data from a UK national milk recording scheme. The data set consisted of 63891 multiple lactation records on diseases (mastitis, lameness, milk fever, ketosis and tetany), fertility traits (calving interval, conception to first service, number of services for a conception, and number of days to first service), dystocia and 305-day milk, fat and protein yield. All traits were analysed by multi-trait repeatability linear animal models (LM). Binary diseases and fertility traits were further analysed by threshold sire models (TM). Both LM and TM analyses were based on the generalized linear mixed model framework. The LM included herd-year-season of calving (HYS), age at calving and parity as fixed effects and genetic, permanent environmental and residual effects as random. The TM analyses included the same effects as for LM, but HYS effects were treated as random to avoid convergence problems when HYS sub-classes had 0 or 100% incidence. Because HYS effects were treated as random, herd effects were fitted as fixed effects to account for effect of herds in the data. The LM estimates of heritability ranged from 0•389 to 0•399 for 305-day milk production traits, 0•010 to 0•029 for fertility traits and 0•004 to 0•038 for diseases. The LM estimates of repeatability ranged from 0•556 to 0•586 for 305-day milk production traits, 0•029 to 0•086 for fertility traits and 0•004 to 0•100 for diseases. The TM estimates of heritabilities and repeatabilities were greater than LM estimates for binary traits and were in the range 0•012 to 0•126 and 0•013 to 0•168, respectively. Genetic correlations between milk production traits and fertility and diseases were all unfavorable: they ranged from 0•07 to 0•37 for milk production and diseases, 0•31 to 0•54 for milk production and poor fertility and 0•06 to 0•41 for diseases and poor fertility. These results show that future selection programmes should include disease and fertility for genetic improvement of health and reproduction and for sustained economic growth in the dairy cattle industry.

Forty-two multiparous Large White sows were used to investigate the effect of diurnally fluctuating temperature (T) on lactation performance and feeding behaviour. The animals were allocated to one of the four thermic treatments: constant T at 25°C (25C) and 29°C (29C) or equal-mean diurnal cyclic T varying from 21 to 29°C (25V) and from 25 to 33°C (29V). Photoperiod was fixed to 14 h of light. The sows were given food ad libitum between the 7th and the 19th day post partům. Lactation performance was measured for all sows whereas the feeding behaviour was recorded only on 28 sows. The ad libitum food intake was comparable at 25C and 25V (6•31 kg/day) as were milk production and body reserves mobilization. In contrast, food intake at 29V was higher than at 29C (4•53 v. 3•48 kg/day) with no difference in milk production between the two treatments. The increased daily food intake at 29V resulted from higher intakes over the coolest periods of the day and especially during the dark period. Neither meal size nor daily number of meals were significantly affected by T. Feeding behaviour was mainly diurnal but with differences between treatments: 0•90 of total food intake at 29C v. 0•78 at the other three T It appears that the effects of diurnally fluctuating T on lactation performance of sows depend on the mean level of T

A crossbreeding experiment involving Timahdit (T), D'man (D) and improved sire breeds (M) was conducted to compare lamb production in five crossbreeding types: D ✕ D, T ✕ T, D ✕ T (DT), M ✕ T, and M ✕ DT lambs. Reproductive and production traits were analysed in 1187 litters, 1586 lambs born and 1346 lambs weaned, progeny of 605 ewes. Effects of crossbreeding type, year of birth, sex of lamb, age of dam, and type of birth were significant on the majority of traits studied. The D ✕ D and M ✕ DT crossbreeding system showed the highest litter sizes at lambing and at weaning with respective values in D ✕ D (2·17, 1·34) and M ✕ DT (1·72, 1·39). Ewes bearing the M ✕ DT cross lambs showed the highest (P < 0·05) litter weight at weaning (28·28 kg) followed by those with M ✕ T (23·14 kg), and D ✕ D (22·53 kg) lambs. M ✕ DT and M ✕ T lambs were heavier and grew faster than the other lambs. On the other hand, lamb survival rates and growth traits were the lowest in D ✕ D but those in T ✕ T and D ✕ T genetic types of lamb were intermediate. Results showed that D as a dam breed had a favourable effect on litter size (P < 0·01) but unfavourable effect on lamb survival and birth weight. The reproductive performance of DT crossbred ewes, due to their high prolificacy and lamb survival, associated with the favourable effect of an improved terminal sire (M) for growth traits, indicated that the three breed cross (M ✕ DT) could enhance lamb production in Morocco.

This study investigated the effect of the change of diet and feeding regimen at weaning on myoelectrical activity of the intestine of piglets. For this purpose the electromyographic recordings of duodenal myoelectrical activity were carried out in relation to the different weaning status of piglets. Six piglets, in two experimental trials were surgically modified with two serosal, bipolar electrodes on the duodenum. The myoelectrical activity was recorded in the same piglets before weaning when they were sucking their sow and after weaning when the diet was changed to solid dry food (standard commercial concentrate for weaned pigs). In sucking piglets the intestinal myoelectrical activity pattern exhibited triple-phased migrating myoelectric complex (MMC), undisturbed by sow nursing. After weaning, feeding with solid food induced a long-term post-prandial pattern with higher frequency of electrical response activity (ERA) when compared with phase II of the MMC. The duration of the MMC cycles increased with time over the experiment by proportionately 0•11 and 0•14 in the periods before and after weaning. However, weaning significantly shortened MMC cycle duration by proportionately 0•21. The duration of phase II was significantly prolonged with time over the experiment by 0•07 to 0•10 and it was not affected by weaning. Phase III of MMC were of constant duration over the whole experimental period.

In summary, changes in the diet and feeding regimen have an influence on the characteristics of intestinal myoelectrical activity in piglets around weaning.

In the present study body condition scores (BCS), ultrasound fat thickness and ultrasound m. longissimus dorsi thickness as well as body measurements and management factors were recorded repeatedly during lactation in 71 Holstein-Friesians, 71 Jerseys and 71 Holstein-Jersey F1-crosses (first to ninth lactation) on four feeding regimens. BCS were analysed with ultrasound measurements as explanatory variables by mixed models. A compound symmetry structure for the variance components was applied. The models were also tested for an autoregressive error structure [AR(1)]. Ultrasound fat thickness and ultrasound m. longissimus dorsi thickness explained most of the variability in BCS. Coefficients of determination were between 0•84 and 0•85. Management factors such as feeding group and stage of lactation (week of taking measurements) and the breed type ✕ lactation interaction were, although significant, not relevant for the fit. Holsteins tended to have lower scores than F1-crosses and Jerseys and younger cows tended to have higher scores than older cows. Despite small differences between breeds, Edmonson’s BCS proved to be consistent within each breed type; thus BCS can be applied to various dairy breeds.

This study investigated the factors affecting milk production and lactation curve parameters from the complete lactations of Awassi dairy sheep. The animals were kept in a single flock under intensive management and milked twice daily starting at lambing. Lambs were removed from the ewes at birth into an artificial rearing unit. The results of the analyses of 3740 complete lactations showed a mean litter size of 1·28 lambs born per ewe lambing and average total milk yield of 506 l from lactations 214 days in length and with an average lambing interval of 330 days. Mean lactation number was 3·71 and ewes conceived on average in the 6th month of the lactation. The lactations peaked on day 45 at a yield of 3·44 l. The maximum milk secretion potential of the ewes was 3·9 l/day, with milk yield increasing at 62 g/day mid way between lambing and peak yield and declining at 16·5 g/day mid way between peak and the end of lactation. Age at first lambing, lactation number, litter size, month of lambing and month of conception during the lactation had significant effects (P < 0·05) on some or all of the lactation parameters investigated. Relatively high milk yield was obtained in lactations starting in the January to March period. The monthly effect on milk production was explained by significant (P < 0·05) heat load and photoperiod effects. High milk production was found to have a significant (P < 0·05) adverse effect on reproductive performance. Conception followed a significant (P < 0·05) short term variation in milk production.

In ruminants and humans, the majority of whole body glucose utilization is not mediated by insulin. However, while in man most non-insulin-mediated glucose utilization (NIMGU) occurs in the brain, in ruminants the locations of NIMGU remain less well defined. As fasting would be expected to limit NIMGU to what would be regarded as an essential minimum, two studies were performed to establish the contribution of NIMGU to total glucose metabolism in fed and fasted sheep. Each study used four adult castrated male sheep. In study 1, a primed continuous infusion of U- [13C] glucose was begun at time 0 and continued for 7 h. After 3 h of isotope infusion (basal period) somatostatin (0•417 µg/kg per min; SS) was administered for 4 h, either alone (SS-only) or together with insulin (1•0 mU/kg per min; SS + insulin) with normal glucose to maintain euglycaemia for 2 h. Normal glucose was then infused for both the SS-only and SS + insulin treatments to induce and maintain hyperglycaemia over the final 2 h of the experiment. In study 2, fed or 72-h fasted sheep were infused with 6-[3H] glucose from time 0 for 8 h, with SS infusion starting at 3 h and continuing for 5 h. After 3 h of SS infusion, glucose was infused to induce and maintain hyperglycaemia. In both studies SS infusion inhibited insulin secretion, however in study 2, SS in fed sheep caused hyperglycaemia; this effect was not significant in the fasted animals. The rate of glucose utilization was reduced by SS-only as it eliminated insulin mediated glucose uptake (IMGU); under such conditions whole body glucose disposal should be NIMGU. In fed sheep, average NIMGU levels represented between proportionately 0•61 and 0•67 of the basal glucose metabolic clearance rate. During the infusion of SS + insulin in fed sheep, NIMGU fell to 0•34 during euglycaemia and 0•33 during hyperglycaemia, as the infused insulin caused IMGU to predominate. In fasted sheep the absolute rates of both IMGU and NIMGU were reduced, though NIMGU as a proportion of total turn-over (IMGU + NIMGU) increased to 0•88 of glucose metabolic clearance. Calculations suggest that, in contrast to man, only a minor proportion of NIMGU is utilized by the brain and central nervous system in fed or fasted sheep. It is suggested that skeletal muscle and the gastro-intestinal tract may make a major contribution to NIMGU, even in fasted sheep.

The intakes and in vivo apparent digestibilities (AD) of four forages: hay (H), haylage (HY), big-bale silage (BB) and clamp silage (CS), were investigated in Welsh cross pony geldings (live weight (LW) ca. 330 kg). The trial was a 4 ✕ 4 Latin-square design with diets offered at 1•65 g/kg dry matter (DM) per100 kg LW per day, in two equal meals. Food and faecal samples were analysed for DM, organic matter, crude protein (CP), gross energy, calcium (Ca), phosphorus (P), magnesium (Mg) and non-starch polysaccharide (NSP) composition and content. Significant differences (P < 0·05) in DM intakes (DMI) g/kg M0·75 were recorded between foods, where HY = BB = H > CS. For all measurements AD was significantly (P < 0·05) higher for BB and CS than for H, with HY being intermediate in all but digestibilities of Ca and Mg. Digestibility of NSP of BB and CS were significantly (P < 0·05) greater than for H and HY. The digestible energy (DE) of H, HY, BB and CS were 5·75, 9·09, 9·83 and 11·98 MJ/kg DM respectively, which coupled with the corresponding DMI resulted in all foods but H meeting the theoretical daily DE requirements of the ponies. Similarly, theoretical digestible CP requirements were met on all diets except H. NSP fractions accounted for 0·5 of daily DE in both H and BB, which were significantly (P < 0·05) higher than for CS and HY at 0·4 and 0·2 respectively. These results indicate that CS, BB and HY are readily digested by ponies and thus offer suitable high-energy alternatives to hay in horse rations.

This study investigated the effects of dietary n-3 polyunsaturated fatty acids (PUFA) on muscle fatty acid composition and content in two cattle breeds; the Holstein-Friesian, a dairy breed, and the Welsh Black, a traditional beef breed. Animals were kept on ad libitum grass silage and one of three concentrates varying in the source of fat; Megalac (high in C16 : 0), formaldehyde treated whole linseed (high in C18 : 3 n-3) and a combination of formaldehyde treated whole linseed and fish oil (high in C20 : 5 n-3 and C22 : 6 n-3). The concentrates were offered at approximately 0·4 of total dry matter intake. Samples of m. longissimus thoracis from Holstein-Friesians contained higher total amounts of fatty acids (P < 0·05) than that of Welsh Blacks in neutral lipid, but the phospholipid fatty acid content was similar between the breeds. Over all treatments, the proportion of C18 : 3 n-3 was higher (P < 0·001) in muscle neutral lipid of Welsh Blacks and the proportions of C18 : 3 n-3 and C18 : 1 trans were higher (P < 0·05 and P < 0·001, respectively) in their subcutaneous adipose tissue. Feeding linseed increased the amounts of C18 : 3 n-3 and also C20 : 5 n-3 in muscle phospholipids suggesting chain elongation and desaturation of C18 : 3 n-3 had occurred. The concentration of C20 : 5 n-3 was significantly higher (P < 0·05) in muscle phospholipids of Welsh Blacks while no differences were found for C18 : 3 n-3 and C22 : 6 n–3. However, when expressed as a proportion of total fatty acids, both C20 : 5 n-3 and C18 : 3 n-3 were significantly higher (P < 0·001) in the Welsh Black phospholipids. These differences resulted in a significantly higher P : S ratio of the muscle total fat (P < 0·05) in the Welsh Black than in the Holstein-Friesian but P : S was not affected by diet. On the other hand, the n-6 : n-3 PUFA ratio was significantly lower in the Welsh Black, reflecting the higher n-3 PUFA content. This ratio was lower in the linseed and the mixed treatments for both breeds, reflecting higher delivery of n-3 PUFA from these diets. Fortification of the diet with sources of PUFA and exploiting breed differences offer the potential to develop systems to increase human intakes of n-3 PUFA in line with current nutritional recommendations.

The main objective of the experiment was to investigate the conditioned responses of sheep towards food flavours associated with the administration of ruminally degradable protein (RDP) and ruminally undegradable, but readily digestible protein (DUP) sources given either alone or in combination. The experiment consisted of three consecutive periods during which sheep were conditioned to associate a flavoured food with a nutritive stimulus (or water, W). Two foods (basal and novel test) with different crude protein (CP; 92 and 64 g/kg dry matter (DM) respectively) and similar metabolizable energy (≊ 9 MJ/kg DM) contents were used on a total of 48 Texel ✕ Greyface female sheep. The basal food was offered during non-experimental (rest) days whereas the test food was used in combination with two flavours, orange and aniseed, during experimental days. Food was presented for 8 h (09:00 to 17:00 h) daily throughout the experiment. Two nutritive stimuli (casein, C, and formaldehyde treated casein, FC) were chosen such as to provide major contrasts in their RDP and DUP contents, on an isonitrogenous basis. Each dose (50 g) of a particular nutritive stimulus was administered by gavage through a stomach tube twice daily (at 10:00 and 14:00 h). Sheep were randomly assigned to one of four (C v . W, FC v . W , C v . FC, C v . FC + C) treatments (no. = 12 per treatment). For the first 2 days (days 1 + 2) of each conditioning period half of the sheep within each treatment were offered one flavoured food paired with the administration of C (treatments C v . W , C v . FC and C v. FC + C) or FC (treatment FC v. W). The other half were offered the opposite flavoured food paired with the administration of water (treatments C v . W and FC v . W), FC (treatment C v . FC) or C + FC (treatment C v . FC + C). There followed 2 days (days 3 + 4) of rest and for the 2 days subsequently (days 5 and 6) received the opposite flavoured food and the opposite stimuli to that received earlier. In the morning of day 7 sheep were offered a choice between the two flavoured foods for 20 min. After the completion of the preference test sheep were offered the basal food. The same procedure was followed for each of three conditioning periods (i.e. each animal followed the same flavour/stimulus association throughout the experiment). The design was balanced for order of flavour and stimulus presentation. Sheep preferred the flavoured food associated with C (P < 0·05) or FC (P < 0·01) over the opposite flavoured food associated with water in C v . W and FC v . W treatments respectively. In the C v . FC treatment sheep showed a strong preference for food flavours associated with the administration of FC to those associated with C (P < 0·05). In the C v. FC + C treatment sheep showed equal preference towards the food flavours associated with either stimuli. These results: (i) support the view that sheep are able to form learned preferences for food flavours associated with the administration of protein, and (ii) suggest that sheep are able to distinguish between food flavours associated with the administration of both RDP and DUP sources. Sheep preferred flavours associated with DUP administration only over flavours associated with RDP administration only; however, such preferences did not develop when DUP was administered concurrently with RDP. Given the learned responses of sheep towards flavours associated with RDP and DUP the expectation is that they may be able to select their diet on the basis of these qualities when they are offered a choice.

A preliminary study was conducted to quantify the lipid produced by differentiated 3T3-L1 cells after incubation in Dulbecco’s Modified Eagle Medium (DMEM) containing 10% foetal bovine serum (FBS), supplemented with or without dimethyl-sulphoxide (DMSO; 9•6 g/l) and acetone (1•2 g/l). The two media treatments were applied to 3T3-L1 cells, plated at either 15K or 30K cells per well in 24-well plates. Cells were grown to confluence (96 h) and then treated with dexamethasone, methyl-isobutylxanthine and insulin for 48 h and later maintained in their respective media treatments for another 144 h. Cells from each treatment were recovered after two, 5-min incubations with trypsin, washed and resuspended in DMEM and counted on a haemocytometer. The lipid in the cells was extracted with hexane derivatized with tetramethyl-guanidine and analysed by gas chromatography. Final mean cell density was 6•8 (s.e. 0•18) ✕ 105 and 4•6 (s.e. 0•19) ✕ 105 when initially plated at 30K and 15K cells per well, respectively. Inclusion of DMSO and acetone in the medium did not affect final cell numbers. Plating density did not affect concentration of lipid (0•55 (s.e. 0•08) mg per 1 ✕ 105 cells) but inclusion of DMSO and acetone led to overall decreases in total lipid concentration. Results indicate that initial plating density influenced final cell number in treatment cultures, but that DMSO and acetone treatments only had an effect on final lipid concentration. Collectively, these data suggest that the application of treatments to cell cultures may be influenced by the carrier vehicle that the treatment is contained in and this should be considered when developing an in vitro system to evaluate growth and development of adipocytes.

The purpose of this study was to estimate the heritabilities and the genetic correlations of osteochondrosis in different joints and to estimate genetic correlations between osteochondrosis, leg weakness and production traits. The humerus condyles, anconeal process, distal ulna growth line, femoral condyles, distal tibia and medial trochlear ridge of talus on both sides of the animals were examined radiologically for osteochondral lesions and scored from 1 to 5 with increasing severity. The boars were also scored for 13 different leg weakness traits on a scale from 1 (normal) to 5 (very severe changes). During a 3-year period, a total of 2042 Landrace boars from 256 sires and 1946 Yorkshire boars from 240 sires were examined at a mean weight of 93 kg. The data were analysed by animal models for each breed. The Landrace was found to be more severely affected than the Yorkshire regarding osteochondrosis in all localities expect the anconeal process. The genetic correlations between left and right side scores of the osteochondral trait were close to 1. This indicates that genetically the same trait is measured in the left and in the right side of the animal. The heritability of average osteochondrosis scores was low to moderate ranging from 0•08 to 0•39 (s.e. between 0•02 and 0•04). The genetic correlations between osteochondrosis in the different body localities were low, indicating that osteochondrosis is not a generalized disease. The Landrace was more severely affected than the Yorkshire regarding all leg weakness symptoms except buck-kneed forelegs, forelegs turned out and weak pasterns on forelegs. The heritability of leg weakness traits ranged from 0•01 to 0•35 (s.e. between 0•01 and 0•04). Genetic correlations between osteochondrosis and leg weakness showed a clear picture for the Yorkshire breed regarding the humeral condyles: positive correlations with buck-kneed forelegs, forelegs turned out, stiff in front and rear. In both breeds osteochondrosis in femoral condyles showed a high positive correlation with hind legs turned out and a lower positive correlation with stiff in front. The sum of osteochondrosis traits (sumost) was unfavourably genetically correlated with daily gain, whereas the sum of leg weakness traits (sumleg) was unfavourably correlated with lean meat percentage in both breeds. The correlation between the summary measures sumost and sumleg was 0•09 (s.e. 0•11) in the Landrace and –0•07 (s.e. 0•12) in the Yorkshire.