The responses to supplements differing in protein concentration and degradability were measured in lactating ewes and their twin lambs when offered fresh ryegrass either cut or grazed. Housed Scottish Halfbred ewes, offered fresh-cut grass ad libitum received no supplement (N) or supplements with barley and maize starch (B); barley and soya-bean meal (S); barley, soya-bean meal and fish meal (SF) or barley and fish meal (F) in weeks 2 to 7 of lactation. By feeding supplements, herbage organic-matter (OM) intake was depressed (2·00 v. 1·74 kg/day). Mean daily milk yield was increased when protein supplements were given and, because milk protein concentration was higher for supplement F and similar for all other diets, mean daily milk protein output increased with increasing fish meal in the diet. Milk yields were N 2·55, B 2·59, S 3·17, SF 3·15 and F 3·17 kg/day. Total milk solids and fat concentrations were also higher for S, SF and F than N or B. Lambs from ewes supplemented with protein grew faster and the ewes generally lost less weight and body condition compared with unsupplemented ewes.

At pasture, Masham ewes grazed at herbage allowances of either 4 (L) or 10 (H) kg OM per day and received no supplement (N) or supplements B or F, for the first 6 weeks of lactation and then, in weeks 7 to 12, grazed without supplements. For NL, BL, FL, NH, BH and FH respectively lamb growth rates from birth to 6 weeks were 235, 242, 274, 267, 286 and 302 g/day; from birth to 12 weeks were 210, 209, 249, 255, 275 and 287 g/day and losses in ewe body-condition score from birth to 12 weeks were 1·28, 1·22, 1·06, 0·97, 0·62 and 0·76.

It is concluded that protein supplements increased milk yield and lamb growth rates and that the response tended to be greater with fish meal.

Iron-deficiency anemia is a public health concern that frequently occurs in pregnant mammals and neonatal offspring. Ferrous N-carbamylglycinate chelate (Fe-CGly) is a newly designed iron fortifier with proven effects in iron-deficient rats and weanling piglets. However, the effects of this new compound on pregnant mammals are unknown. Therefore, this experiment was conducted to evaluate the effects of Fe-CGly on sow reproductive performance and iron status of both sows and neonatal piglets. A total of 40 large-white sows after second parity were randomly assigned to two groups (n=20). They were receiving a diet including 80 mg Fe/kg as FeSO4 or Fe-CGly, respectively, from day 85 of gestation to parturition. The serum (day 110 of pregnancy) and placentas of sows were sampled. Litter size, mean weight of live born piglets, birth (live) litter weight, number of live born piglets, and the number of still-born piglets, mummies, and weak-born piglets were recorded. Once delivered, eight litters were randomly selected from the 20 litters per treatment, and one new-born male piglet (1.503±0.142 kg) from each selected litter was slaughtered within 3 h after birth from the selected litters, without colostrum ingestion. The serum, longissimus muscle, liver and kidneys of the piglets were collected. The iron status of the serum samples and the messenger RNA level of iron-related genes in the placenta, liver and kidney were analyzed. The results showed that litter weight of live born piglets was higher (P=0.030) in the Fe-CGly group (19.86 kg) than in the FeSO4 group (17.34 kg). Fe-CGly significantly increased placental iron concentration (P<0.05) of sows. It also significantly increased iron saturation and reduced the total iron-binding capacity of piglets (P<0.05) at birth. However, the results revealed that supplementation of Fe-CGly in sows reduced liver and kidney iron concentration of neonatal piglets (P<0.05), indicating decreased iron storage. In addition, the concentration of iron in the colostrum was not significantly changed. Therefore, the present results suggested that replacement of maternal FeSO4 supplement with Fe-CGly in the late-gestating period for sows could improve litter birth weight, probably via enhanced iron transportation in the placenta.

The effects of the routine stressful stimuli of handling, transport and slaughter on the plasma concentrations of cortisol and β-endorphin have been studied in lambs. Blood samples were obtained from group 1 lambs after rounding up, after transport and at slaughter. Group 2 lambs were treated similarly except that blood was collected only at slaughter. Group 3 lambs served as controls and were blood sampled twice daily for 5 days to accustom them to handling before being slaughtered. Plasma cortisol and β-endorphin concentrations were increased above control levels by rounding up and transport, and were further increased at slaughter. Group 3 lambs, however, had very much lower β-endorphin levels at slaughter than the other two groups, although their cortisol levels were similar, β-endorphin concentrations declined during the 5-day blood sampling period in group 3 animals but cortisol levels were unchanged. The results suggest that although levels of both hormones are increased by stress, they are not necessarily released concomitantly.

Blood serum free fatty acid (FFA) levels have been measured in sheep subjected to: (a) short periods (20–24 hours) of fasting, (b) physical and emotional disturbances associated with experimental handling, and (c) exposure to cold temperatures when either pregnant or unmated.

The first two factors acted additively, each causing a small elevation of about 100–200 μ-equiv/litre above the pre-existing FFA level. The effect of short-fasting gradually disappeared during the first 6 hours after feeding; the effect of experimental disturbance lasted less than 2 hours.

The effect of severe cold treatment (exposure to approximately 60°C subcriticai ambient temperatures for 2–10 hours) was very marked, producing mean FFA elevations of about 2000 μ-equiv/litre.

Mild cold exposure (3−8°C below the critical temperature), even when maintained for several days, produced little change in the FFA levels already typical of either well-fed or short-fasted sheep. Exposures of moderate intensity (25°C below the critical temperature) apparently produced small elevations in short-fasted sheep only.

It was concluded that a large increase in FFA level was the normal response to acute cold exposure. Elevations due to other factors were, in the context of these experiments, very small. Within the normal range of response to cold exposure there was considerable individual variation in the degree of FFA elevation, but this variation was not generally related to cold resistance expressed as the ability to maintain rectal temperature. However, a few sheep which failed to raise FFA values to the normal extent did show poor cold resistance.

Five species of alpine pasture plants from the Pyrenees representing 3 botanical groups: grasses (Festuca eskia, Nardus stricta), forbs (Anthyllis vulneraria, Galium verum) and shrubs (Echinospartum horridum), were collected monthly from June to September and analysed for nitrogen (N) content, cell wall composition, in vitro enzymatic digestibility (DMDe) and volume of gas produced by microbial fermentation. Among the dicotyledenous varieties, A. vulneraria and G. verum showed the highest nutritive value whilst that of E. horridum was low due to high lignin content. Grasses showed moderate nutritive values in June rapidly decreasing thereafter. Nitrogen content and organic matter digestibility (OMDg) of A. vulneraria remained relatively constant through the sampling period whereas it abruptly decreased for remaining species from July. Gas production significantly differed among species during the first 48 h of microbial fermentation but not at later stages of fermentation. Collection date did not affect gas production before 24 h of incubation but significant differences were found thereafter with samples from June and July being more degraded than from August and September. Principal component analysis associated OMDg positively with N content and gas production and negatively with fibre content. Lignin proportion did not significantly correlate with gas production or with OMDg, suggesting that the degree of lignification is not the only factor affecting microbial fermentation but other factors such as lignin tissue locations may be involved. A. vulneraria has been revealed as very good forage with a high potential in extensive animal production systems. Both OMDg and DMDe methods seem more accurate than chemical analyses for evaluating forages at different stages of maturity.

The growth of Southdown and Clun lambs was studied over the period birth to 415 days of age.

At birth, 50, 100, 150 and 200 days of age five lambs of each breed, and at 415 days three lambs of each breed, were slaughtered and their body composition determined by dissection.

The relative growth of lean, bone and total body fat was not influenced by breed. At each age both Cluns and Southdowns had similar proportions of total body fat, and were considered to be at the same stage of maturity.

There was a breed difference in fat partitioning, with the Clun depositing proportionately more of its total body fat intra-abdominally, compared with the Southdown. However, there was no significant effect of breed on the growth of individual fat depots relative to total fat. From earliest to latest the order of maturity was pericardial, intermuscular, perirenal-retroperitoneal, mesenteric, subcutaneous and lastly, omental fat.

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.

Twenty-four pregnant Scottish Blackface ewes were divided into three temperature-treatment groups 14 days before expected lambing: closely shorn and kept at 6°C (cold treatment, CD); in full fleece at 26°C (warm treatment, WM); and in full fleece at 6°C (controls, CL). Food allocation and intakes were similar for each group. Their lambs were tested for cold-induced summit metabolic rate capability (SMR) on the day of birth at a mean age of 12 h using water immersion to provide cooling. On the following day, the calorigenic response to subcutaneous injections of noradrenaline (NA) was measured to assess non-shivering thermogenesis capability. The ewes were blood-sampled during pregnancy and the lambs before and after the SMR test.

In the ewes, blood glucose and free fatty acid levels were higher during cold treatment, but not significantly so. Blood glucose was lower in lambs from CD ewes (CD lambs) before SMR tests; other differences were not significant.

During the cold test, SMR was highest in CD lambs, but not significantly so. Rectal temperature declined least during test in the CD lambs (P < 0·05).

The peak metabolic response (PMR) following NA injection was about 1·5 times greater in CD lambs than in the CL and WM lambs (P < 0·05). The mean elevation of PMR over thermoneutral metabolic rate was respectively: 2·8, 1·8 and 1·7 times in the CD, CL and WM lambs (P < 0·05), and this elevation was sustained for longer in the CD lambs (P < 0·01). Thus, the total metabolic response to NA was markedly greater in CD lambs.

It was concluded that cold exposure during late pregnancy favoured the deposition of (or checked the normal decline in) foetal brown adipose tissue, so raising the neonatal capacity for non-shivering thermogenesis.

Up to the 18th century, the prevailing view of reproduction, or ‘generation’ as it was referred to, was that organisms develop from miniatures of themselves, termed preformation. The alternative theory, epigenesis, proposed that the structure of an animal emerges gradually from a relatively formless egg. The teachings of the Ancient Greeks who argued either that both sexes each contributed ‘semen’ to form the embryo, or held a more male-centred view that the female merely provided fertile ground for the male seed to grow, dominated thinking until the 17th century, when the combined work of numerous scholars led to the theory that all female organisms, including humans, produced eggs. The sequence of events leading to the commercial use of artificial insemination (AI) date back to the discovery of sperm in 1678, although it took almost 100 years to demonstrate that sperm were the agents of fertilisation and a further 100 years for the detailed events associated with fertilisation to be elucidated. The first successful AI, carried out in the dog, dates back to 1780 while it was not until the early to mid-1900s that practical methods for AI were described in Russia. Inspired by the Russian success, the first AI cooperative was established in Denmark in 1936 and later in the United States in 1938. The next major advances involved development of semen extenders, addition of antibiotics to semen, and the discovery in 1949 that glycerol protected sperm during cryopreservation. Almost four decades later, the flow cytometric separation of X- and Y-bearing sperm opened a new chapter in the application of AI for cattle breeding. As we look forward today, developments in imaging sperm and breakthroughs in gene editing and stem cell technology are opening up new possibilities to manipulate reproduction in a way never thought possible by the pioneers of the past. This review highlights some of the main milestones and individuals in the history of sperm biology and the development of technologies associated with AI in cattle.

It is well known that energy plays an important role in sow growth and development. Increasing the utilization of lipids will be beneficial to sows. Emulsifiers are substances which stabilize mixtures and prevent oil and water from separating, thereby enhancing the digestion of lipids. This study was conducted to evaluate the effect of dietary emulsifier (lysophospholipids (LPL)) supplementation in diets differing in fat contents on growth performance, nutrient digestibility and milk composition in lactating sows, as well as performance and fecal score in piglets. A total of 32 multiparous sows (Landrace×Yorkshire) were used in a 21-day experiment. On day 110 of gestation, sows were weighed and moved into the farrowing facility, randomly assigned in a 2×2 factorial arrangement according to their BW with two levels of LPL (0 and 30 mg/kg) and two levels of fat (4.75% and 2.38% fat; 13.66 and 13.24 MJ/kg). BW loss and backfat thickness loss were decreased (P<0.05) by LPL supplementation. Backfat thickness at weaning was higher (P<0.05) in sows fed LPL supplementation diets. The apparent total tract digestibility of dry matter, nitrogen, gross energy and crude fat in sows fed LPL diets was increased (P<0.05) compared with those fed non-LPL diets. Sows fed the high-fat diets had higher (P<0.05) milk fat on day 10 and milk lactose on day 20 than those fed the low-fat diets. Milk fat and lactose concentrations in LPL supplementation treatments was increased (P<0.05) compared with non-LPL treatments on day 10 and day 20, respectively. Positive interaction effects (P<0.05) between fat and LPL were observed for milk fat concentration on day 10. In conclusion, LPL addition decreased BW loss and backfat thickness loss, improved nutrient digestibility and milk fat as well as milk lactose concentrations. In addition, there was a complementary positive effect of dietary fat and LPL supplementation on milk fat concentration in lactating sows.

The objective of this study was to quantify the genetic associations between a range of carcass-related traits including wholesale cut weights predicted from video image analysis (VIA) technology, and a range of pre-slaughter performance traits in commercial Irish cattle. Predicted carcass cut weights comprised of cut weights based on retail value: lower value cuts (LVC), medium value cuts (MVC), high value cuts (HVC) and very high value cuts (VHVC), as well as total meat, fat and bone weights. Four main sources of data were used in the genetic analyses: price data of live animals collected from livestock auctions, live-weight data and linear type collected from both commercial and pedigree farms as well as from livestock auctions and weanling quality recorded on-farm. Heritability of carcass cut weights ranged from 0.21 to 0.39. Genetic correlations between the cut traits and the other performance traits were estimated using a series of bivariate sire linear mixed models where carcass cut weights were phenotypically adjusted to a constant carcass weight. Strongest positive genetic correlations were obtained between predicted carcass cut weights and carcass value (min rg(MVC) = 0.35; max rg(VHVC) = 0.69), and animal price at both weaning (min rg(MVC) = 0.37; max rg(VHVC) = 0.66) and post weaning (min rg(MVC) = 0.50; max rg(VHVC) = 0.67). Moderate genetic correlations were obtained between carcass cut weights and calf price (min rg(HVC) = 0.34; max rg(LVC) = 0.45), weanling quality (min rg(MVC) = 0.12; max rg(VHVC) = 0.49), linear scores for muscularity at both weaning (hindquarter development: min rg(MVC) = −0.06; max rg(VHVC) = 0.46), post weaning (hindquarter development: min rg(MVC) = 0.23; max rg(VHVC) = 0.44). The genetic correlations between total meat weight were consistent with those observed with the predicted wholesale cut weights. Total fat and total bone weights were generally negatively correlated with carcass value, auction prices and weanling quality. Total bone weight was, however, positively correlated with skeletal scores at weaning and post weaning. These results indicate that some traits collected early in life are moderate-to-strongly correlated with carcass cut weights predicted from VIA technology. This information can be used to improve the accuracy of selection for carcass cut weights in national genetic evaluations.

Stemming from The Worldwide Donkey Breeds Project, an initiative aiming at connecting international researchers and entities working with the donkey species, molecularly tested pedigree analyses were carried out to study the genetic diversity, structure and historical evolution of the Andalusian donkey breed since the 1980s to infer a model to study the situation of international endangered donkey breeds under the remarkably frequent unknown genetical background status behind them. Demographic and genetic variability parameters were evaluated using ENDOG (v4.8). Pedigree completeness and generation length were quantified for the four gametic pathways. Despite mean inbreeding was low, highly inbred animals were present in the pedigree. Average coancestry, relatedness, and non-random mating degree trends were computed. The effective population size based on individual inbreeding rate was about half when based on individual coancestry rate. Nei’s distances and equivalent subpopulations number indicated differentiated farms in a highly structured population. Although genetic diversity loss since the founder generations could be considered small, intraherd breeding policies and the excessive contribution of few ancestors to the gene pool could lead to narrower pedigree bottlenecks. Long average generation intervals could be considered when reducing inbreeding. Wright’s fixation statistics indicated slight inbreeding between farms. Pedigree shallowness suggested applying new breeding strategies to reliably estimate descriptive parameters and control the negative effects of inbreeding, which could indeed, mean the key to preserve such valuable animal resources avoiding the extinction they potentially head towards, making the present model become an international referent when assessing endangered donkey populations.

A 3 to 4 week feed restriction of about 20% to 25% of the free intake is widely applied in rabbit breeding systems to reduce post-weaning digestive disorders. However, a short intensive feed restriction is described in few studies and can be beneficial for growing rabbits due to a longer re-alimentation period. The aim of this study was to evaluate the effect of ad libitum (AL) and two restriction levels of feeding (50 and 65 g/rabbit per day) applied for 1 week on performance, gastrointestinal morphology and physiological parameters during the restriction and during the re-alimentation period. Rabbits were divided into three experimental groups: AL rabbits were fed AL, R1 rabbits were restricted from 42 to 49 days of age and received 50 g daily (29% of AL) and R2 rabbits were restricted at the same age and were fed 65 g of feed daily (37% of AL). In the 1st week after weaning and in the weeks after restriction, all the groups were fed AL. During the restriction period, daily weight gain (DWG) in R1 significantly dropped to 11% (experiment 1) and 5% (experiment 2) compared with rabbits in the AL group, although they were fed 29% of AL, whereas in the R2 group it decreased to 20% (experiment 1) and 10% (experiment 2). In the week following feed restriction, DWG in the restricted groups increased (P<0.001) to 166% and 148% in R1 and to 128% and 145% in R2. Restricted rabbits in both the experiments reached up to 90% to 93% of the final live weight (70 days) of the AL group. Over the entire experimental period, feed restriction significantly decreased feed intake to 85% to 88% of the AL group; however, the feed conversion ratio was lower (P<0.05) only in experiment 1 (−6% in R1 and −4% in R2). Digestibilities of CP and fat were not significantly higher during the restriction period and during the 1st week of re-alimentation compared with the AL group. Significant interactions between feeding regime and age revealed the shortest large intestine in the AL group at 49 days of age and the longest at 70 days in the AL and R1 groups. Small intestinal villi were significantly higher and the crypts were significantly deeper in the restricted groups. It could be concluded that short intensive feed restriction increased digestible area in the small and large intestines, including the height of villi and depth of crypts, which might be involved in the compensatory growth and defence mechanism.

The aim of this research was to investigate how growth hormone (GH) cortisol and some haematochemical parameters could be modified by the stress caused by the stages of shearing in Sarda breed sheep. Five groups of 10 sheep each were formed. Group A, only separated from the flock; Group B, only tied; Group C, both tied and shorn (animals in these three groups were ewe lambs shorn for the first time); Group D, adult females both tied and shorn; and Group E, adult entire males both tied and shorn (animals in these two groups had been shorn previously). Five blood samples were taken from each animal: the day before treatment (first sample); at the start of the treatment (second sample); in the middle of shearing for Groups C, D and E, 10 min after separation in Group A and 10 min after tying in Group B (third sample); at the end of treatment (fourth sample); and on the day after treatment (fifth sample). Plasma GH levels showed a decrease (P < 0.01) in Groups A, B, C and D during treatment (third and fourth samples), while Group E only at the end of shearing (fourth sample). In the third sample, the highest GH levels were recorded for Group E (P < 0.05), while it was recorded in the fourth sample for Groups A and E (P < 0.05). Cortisol levels showed a clear increase (P < 0.01) in all groups during treatment, but Group A showed a decrease in the fourth sample in comparison to the third sample. Males in the second, third and fourth sample and Group A only in the fourth sample showed lower cortisol levels when compared with the other groups (P < 0.05). Plasma glucose levels showed an increase (P < 0.01) in all groups during treatment but Groups B, C and E showed the highest values (P < 0.05). Magnesium (Mg) showed an increase in all groups in the third and fourth sample, while sodium (Na), in the same samples, only in Groups B, C and D. Potassium (K) values showed a significant decrease (P < 0.05) only in Groups C and D at the end of shearing. These results show that GH secretion is influenced by all the stress procedure: separation, tying and shearing. Shearing, even if necessary for animals, causes a significant change of the blood parameters involved in the stress response.

There is a large demand for holistic welfare assessment systems that result in a singular balanced summary of welfare. The Welfare Quality® (WQ) broiler protocol summarizes 18 welfare measures into four principles (‘good feeding’, ‘good housing’, ‘good health’ and ‘appropriate behaviour’), which are then integrated into one overall category (‘excellent’, ‘enhanced’, ‘acceptable’ or ‘not classified’). But the protocol is time consuming which hampers implementation. Furthermore, WQ’s aim to assess animal welfare in a wide range of husbandry systems may decrease its ability to discriminate between flocks from the same system. We applied the protocol in the context of intensive indoor rearing to assess whether it discriminated sufficiently between flocks, could be shortened without losing essential information, and provided a balanced summary of welfare. The vast majority of the flocks (88%) received the same overall classification (acceptable) whilst all other flocks received an adjacent classification (enhanced), suggesting poor discriminative capacity. For 95% of the flocks overall classification was explained by two measures only (‘drinker space’ and ‘stocking density’). A system based on these two measures would reduce assessment time from 3.5 h to a few minutes. However, both measures’ validity can be questioned as they are risk factors for poor welfare rather than animal-based outcome measures and they suffer from methodological weaknesses. Furthermore, the possibility for such an extreme simplification raises doubts on whether the overall classification reflects a balanced summary of different welfare aspects. In line with this, overall classification was not affected by replacing single measures within the ‘good health’ and ‘appropriate behaviour’ principles with realistically attainable minima or maxima for intensively reared flocks. Even replacing either of these two principles entirely with their realistically obtainable minimum or maximum did not affect classification. Such insensitivity to change may discourage attempts to improve the welfare of intensively reared flocks when assessments are made based on the overall classification. This calls for an adjustment of the classification system, which is currently being developed by the Welfare Quality Network.

Two trials were conducted using two breeds of sheep varying in prolificacy but producing high commercial milk yields. In the first, 85 Chios ewes were assigned at 10 weeks before lambing to one of three planes of feeding: L, straw ad libitum; M, straw ad libitum + 0·5 kg concentrates; and H, straw ad libitum +1·0 kg concentrates. Six weeks prior to lambing, treatment L was stopped and all 85 ewes were re-randomized to treatments M and H. They were kept on these treatments until 14 days after lambing. In the second trial, 54 Chios and 56 Awassi ewes were allocated to the M and H treatments 6 weeks prior to lambing. After lambing they were fed ad libitum on straw and concentrates for 28 days.

The mean metabolizable energy intake (Meal/day) over the 6-week period before lambing was 2·78 and 3·96 for Chios ewes in Trial 1, 2·39 and 3·51 for Chios ewes in Trial 2 and 2·66 and 3·72 for Awassi ewes in Trial 2, for the M and H treatments respectively.

In both trials the treatment of the ewes affected the birth v/eight of twin and triplet lambs but not that of singles. In Trial 1, the differences in 14-day milk yield between treatments M and H were highly significant. In Trial 2, however, in which the ewes were fed ad libitum during lactation, no differences in the 14-day or the 28-day milk yields were observed for either breed. It is concluded that milk yields in early lactation are closely related to actual plane of nutrition in lactation but may also be affected by the body condition of the ewe at lambing, which may in turn be influenced by a low level of feeding in pregnancy.

Abstract Acute phase proteins (APP) are released into the circulation in mammals upon infection and may be used to diagnose the health status of managed populations of animals such as pigs. The current study determines APP levels in a population of apparently healthy Large White pigs from a single farm, to address two questions: (1) whether phenotypic associations can be observed between productivity and APP, indicating the effects of possible subclinical infections and (2) whether previous selection for either food intake or ‘lean growth under restricted feeding’ influences APP levels. The APP investigated were alpha1- acid glycoprotein (AGP) and haptoglobin. The APP were measured at 18 and 24 weeks of age in pigs previously selected for high lean growth (no. = 31), low lean growth (no. = 38), high daily food intake (no. = 24) and low daily food intake (no. = 26), but performing under ad libitum feeding conditions. Performance traits and APP levels were constant over the experimental period, indicating that the farm health status did not vary over time. Performance traits and APP were recorded on 119 pigs, of which 80 had both APP and performance measurements. Multiple regression analyses were used to investigate phenotypic relationships between performance traits and APP levels. Plasma concentrations of AGP were higher in 18-week-old pigs compared with 24-week-old pigs (P < 0·01) whereas haptoglobin levels did not vary according to age. Significant sex differences in APP levels were observed. Females had higher circulating levels of AGP than males at both 18 weeks and 24 weeks. Females also had higher levels of haptoglobin at 18 weeks. Levels of AGP had significant negative correlations with daily weight gain (−0·59, P < 0·01 and −0·48, P < 0·05 at 18 and 24 weeks respectively) and with daily food intake (−0·53, P < 0·01 and −0·38, P < 0·05 at 18 and 24 weeks respectively). At age 24 weeks, haptoglobin was negatively correlated with both daily weight gain (−0·35, P < 0·05) and food efficiency (−0·34, P < 0·05). Pigs selected for high lean growth under restricted feeding had higher AGP levels than pigs selected for low lean growth under restricted feeding at 18 (593 v. 332 μg/ml, P < 0·01) and 24 weeks of age (313 v. 219 μg/ml, P < 0·05). Selection for daily food intake did not consistently affect AGP levels, and neither selection criteria influenced plasma haptoglobin concentrations. To conclude, we have demonstrated that amongst contemporaneous pigs of the same genotype, higher systemic AGP levels and, to a lesser extent, higher haptoglobin levels are associated with decreased performance, and that genetic selection for ‘efficient lean growth under restricted feeding’ can increase serum AGP levels.

Multivariate restricted maximum likelihood analyses were carried out for a large data set comprising records for eye-muscle area, fat depth at the 12/13th rib and the rump P8 site, and percentage intramuscular fat, recorded via live ultrasound scanning of Australian Angus cattle. Records on heifers or steers were treated as separate traits from those on bulls. Reduced rank estimates of the genetic covariance matrix were obtained by restricted maximum likelihood, estimating the leading three, four, five, six, seven and all eight principal components and these were contrasted with estimates from pooled bivariate analyses.

Results from analyses fitting five or six genetic principal components agreed closely with estimates from bivariate and eight-variate analyses and literature results. Heritabilities and variances for ‘fatness’ traits measured on heifers or steers were higher than those recorded for bulls, and genetic correlations were less than unity for the same trait measured in different sexes. Eye-muscle area showed little association with the other traits.

Reduced rank estimation decreased computational requirements of multivariate analyses dramatically, in essence corresponding to those of an m-variate analysis for m principal components considered. Five or six principal components appeared to be necessary to model genetic covariances adequately. The first three of these components then explained about 97% of the genetic variation among the eight traits.

A simulation study showed that errors in reduced rank estimates of the genetic covariance matrix were small, once three or more principal components from analyses fitting five or more components were used in constructing the estimates. Similarly, accuracy of genetic evaluation for the eight traits using the first four components was only slightly less than that using all principal components.

Results suggest that reduced rank estimation and prediction is applicable for the eight scan traits considered. The leading three to four principal components sufficed to describe the bulk of genetic variation between animals. However, five or more principal components needed to be considered in estimating covariance matrices and the ‘loadings’ of the original traits to the principal components.

Clinical mastitis records on 36 178 first-lactation Norwegian dairy cattle (NRF) cows, daughters of 245 sires from 5286 herds, were analysed to study the impact of trait definition on estimates of genetic parameters and sire evaluations for clinical mastitis. The opportunity interval for infection, going from 30 days pre-calving to 300 days post partum, was divided into either 11 periods (each 30 days long); four periods ((-30, 0), (1, 30), (31, 120), (121, 300)); a single period (-30, 300) or defined as the interval currently used for sire evaluation in Norway (-15,120). Within each period, clinical mastitis was scored as 1 if it occurred at least once and 0 otherwise. Analysis was with Bayesian threshold models, assuming that mastitis (presence v. absence) was a different trait in each period. By use of multivariate or univariate normal link functions, unobserved liabilities to disease were modelled as a linear function of year of calving, age-season of calving, herd, sire of cow and residual effects. Estimates of heritability of liability to clinical mastitis ranged from 0-06 to 0-14, depending on the model and stage of lactation. In multi-period models, estimates of genetic correlations between periods were positive and ranged from 0-13 to 0-55. This suggests that clinical mastitis resistance is not the same trait in different periods of the first lactation, which is not captured by the single-interval models. The single-interval (-30, 300) model gave slightly smaller sire-specific posterior probabilities of clinical mastitis during the first lactation than the multi-period models. Furthermore, the interval used in current Norwegian sire evaluation understated the posterior probabilities of clinical mastitis, relative to the multi-period specifications. This led to some differences in sire rankings between the four models, although there was agreement between the four- and 11-period models. In conclusion, the multi-period models captured more genetic variation than the single-interval models, but the four-period model gave sire rankings that differed little from those obtained with an 11-period definition of clinical mastitis.