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Sow body composition largely reflects the amount of lean and fat tissue stores in the body, and is measured, managed and reported because traditionally when sows mobilise body tissues in lactation to support piglet growth, adverse consequences in subsequent reproduction may be observed. These consequences are largely driven by metabolic changes exerting negative influences on the reproductive axes through luteinising hormone and follicle stimulating hormone and direct impact on the ovary. This results in sows that take longer to ovulate, have lower ovulation rates and shed poorer-quality oocytes, translating to delayed wean to service intervals, higher pregnancy failure and lower litter sizes. Sow management needs to meet both the needs of the piglet (adequate colostrum and milk intake for survival and growth) and the needs of the sow (successful re-breeding). The way pork producers tackle this is through diets designed to match sow requirements at different production stages. We have recently observed, despite efforts (nutritional challenges), that we are unable to induce fat or lean tissue mobilisation in lactating sows, which is a novel finding, although pig populations such as in the EU, UK and USA would appear to be experiencing similar outcomes. Despite our lower reproductive performance than in much of the rest of the world as a consequence of having a closed genetic herd, the specific genetic selection programs that exist within Australia, and the resultant leaner, more efficient sows, may be a potential explanation. This, coupled with the high lactation feed intakes now commonly reported, means that sows are less likely to become catabolic and so suffer from poor re-breeding outcomes. A conclusion from these findings may mean that we now have an opportunity to feed the lactating sow to better meet the growth and survival needs of piglets, with the knowledge that we will not compromise subsequent reproduction.

Context The Australian pork industry would benefit greatly from further development of export markets across Asia, but due to the small size of the Australian industry and cultural differences between Asia and the West, further insight into research is required for premium product development. Aims Qualitatively assess value in Australian pork across Australian and Chinese consumer groups to investigate perceived differences in cultural attitudes to pork. Methods Qualitative multivariate analysis (QMA). Key results Australian and Chinese opinions of Australian pork products, meat and offal, and farming systems differed significantly. Australian consumers desired expert opinion, traditional meat cuts with minimal packaging, and small-scale production with superior animal welfare. Chinese consumers wanted clean, healthy and versatile products, with consistent quality, without concerns around animal welfare. Conclusions The compatibility of the markets and consumer preferences show great promise for Australian pork holding value in the eyes of Chinese consumers, Implications Results offer insight for future product development for export and targeted domestic markets. Findings will also enable future quantitative research efforts to be more targeted and specific.

The ability to accurately estimate fat mass and fat-free mass (FFM) has the potential to improve the way in which sow body condition can be managed in a breeding herd. Bioelectrical impedance spectroscopy (BIS) has been evaluated as a practical technique for assessment of body composition in several livestock species, but similar work is lacking in sows. Bioelectrical impedance uses population-specific algorithms that require values for the apparent resistivities of body fluids and body proportion factors. This study comprised three major aims: (i) to derive apparent resistivity coefficients for extracellular water (ECW) and intracellular water (ICW) required for validation of BIS predictions of total body water (TBW) in live sows against standard reference tracer dilution methods; (ii) to develop predictions of TBW to body composition prediction algorithms, namely FFM, by developing a body geometry correction factor (Kb) and (iii) to compare the BIS predictions of FFM against existing impedance predictors and published prediction equations for use in sows, based on physical measurements of back-fat depth and BW (P2-based predictors). Whole body impedance measurements and the determination of TBW by deuterium dilution and ECW by bromide dilution were performed on 40 Large White x Landrace sows. Mean apparent resistivity coefficients of body fluids were 431.1 Ω.cm for ECW and 1827.8 Ω.cm for ICW. Using these coefficients, TBW and ECW were over-estimated by 6.5 and 3.3%, respectively, compared to measured reference values, although these differences were not statistically different (P > 0.05). Mean Kb was 1.09 ± 0.14. Fat-free mass predictions were 194.9 kg, which equates to 60.9% of total sow weight, and 183.0 kg for BIS and the deuterium dilution method, respectively. Mean differences between the predicted and measured FFM values ranged from − 8.2 to 32.7%, but were not statistically different (P > 0.05). Method validation (leave-one-out procedure) revealed that mean differences between predicted and measured values were not statistically significant (P > 0.05). Of the impedance-based predictors, equivalence testing revealed that BIS displayed the lowest test bias of 11.9 kg (8.2%), although the P2-based prediction equations exhibited the lowest bias and percentage equivalence, with narrow limits of agreement. Results indicate although differences between mean predicted and measured values were not significantly different, relatively wide limits of agreement suggest BIS as an impractical option for assessing body composition in individual sows compared to the use of existing prediction equations based on BW and back fat.

The growth rate of the young pig is generally much less than it's potential and may be constrained by endocrine status as well as nutrient intake. Growth factors are present in relatively high quantities in colostrum and play an important part in gut development. It is possible that supplementation of colostrum protein isolate may stimulate gut and whole body growth in the pig. Eight male and 8 female (Large White×Landrace) piglets were weaned at 1 d of age after each pig had obtained colostrum from their dam, and were trained to consume one of two liquid diets. The two diets were based on either a colostrum protein isolate (n = 4 males and 4 females) or whey protein concentrate (n = 4 males and 4 females) and were formulated to contain equal levels of crude protein and amino acids. Pigs were fed their diets ad libitum for 28 days after which time 12 pigs were euthanised and various tissues and organs weighed. Pigs were bled for IGF-I analyses at 21 and 28 days of age. Daily gain was higher in pigs consuming the colostrum isolate (171 vs. 216 g/d, p = 0.010), particularly between 2 and 4 weeks of age (212 vs. 298 g/d, p = 0.010). Pigs tended to consume more of the liquid feed containing colostrum isolate (25.5 vs. 29.1 kg, p = 0.074) and gained more live weight per unit of liquid feed (0.203 vs. 0.223 g/g, p = 0.056). There were no effects of sex on growth performance. Pigs consuming the diet supplemented with colostrum isolate had higher (p

The beta-agonist ractopamine is a dietary ingredient that improves growth and increases the lean mass with little change in fat mass in gilts and barrows. Limited data in boars indicate that dietary ractopamine may increase lean tissue and decrease fat deposition, whereas there are no data for immunocastrated boars. The aims of this investigation were 1) to assess whether the growth performance of all sexes could be maintained over 31 d by using a step-up dietary ractopamine feeding program of 5 mg/kg of ractopamine for the first 14 d, then increasing the dose to 10 mg/kg for a further 17 d, and 2) to determine if dietary ractopamine would increase lean mass in all sexes and decrease fat mass in boars and immunocastrated boars. The study involved 286 pigs randomized and proportionally allocated by breed into 24 groups of 11 or 12 pigs at 17 wk of age, with equal groups of boars, immunocastrated boars, and gilts. Dietary ractopamine decreased (P = 0.005) ADFI during the first 2 wk, particularly in the intact and immunocastrated boars, with the reduction in ADFI being maintained in the immunocastrated boars after the increment in dietary ractopamine. Daily BW gain was not altered by dietary ractopamine during the first 2 wk, but was increased (P < 0.001) after the increment in dietary ractopamine. Dietary ractopamine decreased (P < or = 0.033) feed conversion ratio in all sexes with the response being greater after the increase in dietary ractopamine. Carcass weight was increased (P < 0.001) by dietary ractopamine in all sexes, whereas back fat tended (P = 0.076) to be reduced in the immunocastrated boars. Dietary ractopamine increased (P = 0.018) lean tissue mass by 4.0, 4.8, and 6.5 kg in the intact boars, gilts, and immunocastrated boars, respectively. In the entire and immunocastrated boars, the increase in lean tissue was accompanied with a decrease (P = 0.004) in fat mass. There was little effect of dietary ractopamine on fat mass in gilts. However, carcass percent fat was decreased (P = 0.004) and percent lean increased (P = 0.006) in all sexes. Immunocastration caused a decrease in lean tissue mass and an increase in fat mass and an increase in ADFI in the last one-half of the study. Dietary ractopamine may decrease fat mass in intact and immunocastrated boars and offers an excellent means of maximizing the effects of immunocastration and minimizing the increase in fat mass sometimes observed in immunocastrated boars.

Lathyrus cicera is a grain legume that is well adapted to grow in low rainfall regions. However, it contains a neurotoxin, 3-(-N-oxalyl)-l-2,3-diaminopropionic acid (ODAP), which can cause paralysis of the lower limbs, known as "lathyrism". An experiment was conducted to measure the nutrient content and ileal digestible amino acid content of a recently-released low ODAP Lathyrus variety chalus. Chemical analyses and total tract digestibility showed that the new Lathyrus variety chalus contained 0.9 g ODAP/kg, 265 g crude protein/kg and 13.5 MJ digestible energy/kg on an as-fed basis. The ileal digestible nutrient content of chalus was measured with six grower pigs (Large White×Landrace, 43 ± 0.3 kg) fitted with a simple T-piece cannula. The chalus contained 12.9, 1.4 and 5.4 g of apparent ileal digestible lysine, methionine and threonine, respectively/kg. Standardised ileal digestible amino acid content was calculated using published endogenous amino acid losses determined in 34-kg-growing pigs under a protein-free method. The chalus contained 14.3, 1.5 and 6.0 g of standardised ileal digestible lysine, methionine and threonine, respectively/kg.

Capacity to routinely, accurately and cost-effectively measure variation in the nutritional quality of feed ingredients before diet formulation represents a fundamental pillar of sustainable pork production worldwide. Factors driving sustainable pork production include pork price, feed cost, utilisation of co-products and downgraded raw materials and variation in pork production, with all being related to the definition and ultimate nutritional quality of feed ingredients. The present paper defines rapid measures of nutritional quality in feed ingredients for pigs and demonstrates the range that can exist in these parameters, specifically digestible energy of cereal grains and the reactive-lysine concentration of oilseed meals. It provides an overview of the development of near-infrared spectroscopy (NIRS) calibrations for key nutritional-quality parameters and how they are being applied by the pork industry. Adjunct ways to measure nutritional quality of feed ingredients for pigs such as the glucose-release index and how these can be used in conjunction with NIRS are reviewed. The paper reports advanced correlation analysis between chemical components and digestible-energy concentration of cereals, and how these could be used for screening of NIRS outliers, and discusses future opportunities for application of nutritional-quality analysis using NIRS calibrations, including feed intake and portable solutions. Using advanced NIRS calibrations for digestible energy in cereals and reactive lysine in oilseed meals, pork producers will ensure that they make best use of limited resources and, as a consequence, pork will remain a nutritionally accretive food source for increasingly discerning consumers worldwide.

To optimize dietary protein level in relation to growth, semipurified diets with an essential amino acid profile similar to that of the soft body profile were fed for 59 days to young greenlip abalone, Haliotis laevigata (initial shell length, 15–25 mm). Animals were housed in 10-L acrylic tanks, with flow-through seawater supplied at 1 L min–1 (20 °C, salinity= 36 g L–1). Protein level of feeds ranged from 122 g kg–1 to 461 g kg–1 crude protein (CP) on an ‘as is’ basis. Second-order polynomial regression analysis of specific growth rate indicated that maximal growth occurs at 270 g kg–1 CP. The protein and energy components of the feed were estimated to have a digestibility of 71.7% and 55.6%, respectively.

1. The effects of lupin non-starch polysaccharides (NSPs) on apparent metabolisable energy (AME) and composition of digesta from broiler chickens were examined in a dose-response experiment in conjunction with a single combination of 2 commercial enzyme products known from previous studies to partially depolymerise NSPs in diets containing sorghum, casein and lupin kernel. The 7-d experiment was conducted on broiler chickens (24 to 31 d of age) in metabolism cages. 2. The basal diet used in this study contained (in g/kg) sorghum (low tannin) 800, casein 134, celite 20 and vitamins and minerals 46. The inclusion rate for each enzyme product was 0.2 g/kg. Lupin kernel isolate (containing 560 g/kg total NSPs) replaced some of the sorghum and casein. The dose rates of lupin kernel isolate (50, 100 and 150 g/kg) were equivalent to dietary inclusion rates of 80, 160 and 240 g/kg, approximately, of untreated lupin kernel from Lupinus angustifolius cultivar Gungurru. 3. Inclusion of lupin kernel isolate in the diet depressed AME and bird performance, and raised ileal viscosity and excreta moisture, in a dose-dependent manner. 4. A combination of 2 proprietary enzyme products improved dietary AME by 0.3 MJ/kg dry matter. Enzymes reduced excreta moisture when inclusion of lupin kernel isolate was 50 g/kg (equivalent to lupin kernel at 80 g/kg, approximately) but not at higher inclusions. 5. Food enzymes partially depolymerised some insoluble NSPs in lupin kernel isolate, which increased ileal viscosity and soluble NSP content of digesta. 6. It was concluded that development of appropriate exogenous enzyme products could lead to lupin NSPs being used as an energy source for poultry.

Ninety male crossbred pigs were allocated at 30 kg live weight to a 6 5 factorial experiment involving six diets and five levels of feeding where average daily intakes were 1.11, 1.36, 1.67, 1.90 kg and ad libitum between 30 and 60 kg live weight. The control diet contained predominantly animal protein sources, another four diets contained 350 g/kg of either kernels or seeds of either L. angustifolius cv. Gungurru or L. albus cv. Kiev while the remaining diet contained 350 g/kg of peas. All diets were formulated to contain 15.3 MJ DE/kg and 0.7 g available lysine/MJ DE to ensure that dietary protein was adequate. Six estimates of the digestibility of each protein source were determined by the total faecal collection method. The digestible energy contents (SE) of L. angustifolius seed and kernel, L. albus seed and kernel and peas were 15.81 (0.18), 16.85 (0.76), 16.84 (0.34), 17.70 (0.47) and 14.98 (0.15) MJ/kg air dry, respectively. All pigs were killed at 60 kg live weight and the dressing percentage of pigs given L. angustifolius and L. albus diets were 2.6 and 4.7 units lower than the mean dressing percentage of pigs given the other diets. The major factors contributing to this reduction in dressing percentage when lupins were offered to pigs were gut fill and differences in intestinal weight. The relative energy value of the protein sources was assessed by comparing the relationship between the rates of energy deposition in the empty body and DE intake for the diets. The response of energy deposition to energy intake was similar for kernel and seed for both L. angustifolius and L. albus and thus data for kernel and seed were consolidated for both types of lupins. The respective linear relationships between energy deposited in the empty body (E, MJ/day)

In their raw, unprocessed form, lupins have many desirable characteristics for feeding both ruminants and single-stomached animals. An emphasis on these desirable characteristics when formulating diets, combined with an advanced knowledge of how components of lupins can influence nutritional value, will ensure they make a cost-effective contribution to livestock diets. The main lupin species used in livestock diets include Lupinus albus, L. angustifolius and L. luteus. Supplementation of ruminant diets with lupins has been shown to have many positive effects in terms of growth and reproductive efficiency, comparable with supplements of cereal grain. The true value of lupins in ruminants, however, can only be determined following a better definition of animal requirements and a closer match of ration specifications. Pigs can effectively utilize L. angustifolius and L. luteus, but detailed research has yet to reveal the reason for poor utilization of diets containing L. albus. Poultry can tolerate high levels of lupins in their diets but levels are often restricted to avoid problems associated with excess moisture in the excreta. Variable responses to enzymes have been observed when attempting to rectify this problem. Lupins have unique carbohydrate properties characterized by negligible levels of starch, high levels of soluble and insoluble NSP, and high levels of raffinose oligosaccharides, all of which can affect the utilization of energy and the digestion of other nutrients in the diet. In addition to carbohydrates, an understanding of lupin protein, lipid and mineral composition together with a knowledge of potential anti-nutritional compounds is required if the use of this legume is to be optimized.

Near infrared (NIR) spectroscopy is in widespread use at grain receival silos and stockfeed mills to determine the protein and moisture contents of cereals used in livestock feeds. These parameters alone, however, are only the first step in the definition of nutritive value, which is best determined by accounting for the inevitable losses that occur following digestion and absorption within animals. When formulating diets for growing pigs, the greatest cost pressure is against the cost per unit of energy and, hence, digestible energy (DE) is a valuable measure of the nutritive value of cereals for this class of livestock. The DE content of cereals for pigs can vary considerably within a cereal type (in excess of 3 MJ kg−1 DM) and a rapid means of assessing this parameter would improve the accuracy of diet formulations for growing pigs and reduce the cost of the diets. To date the use of NIR to predict DE has been limited by the cost associated with obtaining a sufficient number of samples with in vivo measurements over an adequate range necessary to develop a robust NIR calibration. To overcome this problem, a range of cereals (wheat, barley, sorghum, triticale, maize) that had been fed to pigs experimentally, to determine their DE contents were sourced from Australia, Canada, France and New Zealand. NIR spectra of both whole and milled grain were recorded and used to derive calibrations for DE. A disadvantage of this approach is the influence of interlaboratory variation on the reference sample set and the resulting calibration. This study has, for the first time, demonstrated the value of indicator variables in detecting the presence of, and compensating for, interlaboratory variability in a set of animal nutrition data.

The growing Asian middle class, the proliferation of export markets and a more discerning domestic consumer base are creating new opportunities and challenges for the Australian pork industry. To fully capitalise on these opportunities and face these new challenges, the right questions need to be asked by the Australian pork industry. We need to know not only what our consumers want, but who our consumers are. The present paper aims to demonstrate that novel approaches to investigate consumer attitudes will be required, and it cannot be assumed that current productions systems, products and marketing strategies are optimal for the changing environment and the creation of new premium market opportunities. With new markets and new products come new consumers; identifying who those consumers are, the networks they operate within as food consumers, and what influences their purchasing decisions are the key to their adopting Australian pork as premium produce in a new global market.

Knowledge of amino acid availability in feedstuffs is central to accurate diet formulation. Dietary lysine oxidation was evaluated as a means of predicting dietary lysine availability. Growing pigs (30 kg) were offered control (1.43% lysine), free lysine-supplemented, soybean meal-, or cottonseed meal-supplemented diets. Supplemented diets provided equivalent total lysine (approximately 24.2 g/d at 30 kg BW) but availabilities of lysine, determined by slope-ratio assay, in the free lysine, soybean meal, and cottonseed meal were 100, 90, and 30%, respectively. Feed was offered in eight equally spaced meals per day to achieve three times maintenance energy intake. Following a meal containing L-[U- 14 C]lysine (1 μCi/kg BW), lysine oxidation, as 14 CO 2 expired, was lower (P

Experiments were conducted to determine the effect of heating field peas (Pisum sativum) on the N balance and urine, serum and plasma composition of growing pigs. In the first experiment, four diets containing raw field peas (cv. Wirrega) or field peas heated to 150° (cv. Wirrega), 165° (cv. Wirrega) or 150° (cv. Dundale) for 15 min respectively were formulated to contain 1·15 g ileal digestible N/MJ digestible energy (DE) and 036 g ileal digestible lysine/MJ DE in a sugar-based diet. Digestibility estimates were based on those for the Dundale cultivar of field peas used in previous experiments. Total urine and faeces collection from eight pigs was conducted over two 7 d collection periods with a 7 d diet change-over period. Serial blood sampling from the external jugular vein was conducted on the final day of each collection period. There was no significant difference (P > 0·05) in the N balance or apparent biological value of the field-pea treatments. Pigs fed on diets containing peas heated to 150° (cv. Wirrega) or 165° (cv. Wirrega) had a significantly lower (P < 0·01) daily output of urea and uric acid in the urine, and depressed serum protein and serum urea concentrations. Plasma lysine concentration and daily urine lysine output were not significantly different (P > 0·05) in pigs fed on heated peas. Protein excretion in the urine of pigs fed on diets containing peas heated to 165° increased 3–7 times (depending on estimation technique) the level observed in pigs fed on diets containing raw peas. A second experiment was conducted to determine the apparent ileal digestibility of N and amino acids in cv. Wirrega field peas. This study revealed that N digestibility (0·44) and lysine digestibility (0·35) in peas heated to 165° were significantly lower than the cv. Dundale estimates (0·57 and 0·62 respectively) used in diet formulations. The depressed serum and urine variables in pigs fed on heated peas were attributed to overestimation of digestibility. The results exemplify the fact that it is not possible to draw general conclusions as to the effects of heat on any particular protein concentrate. Variability in N balance experiments and problems associated with urine analysis are suggested as likely reasons for the current study not reflecting poor utilization of ileal digestible lysine from heat-treated field peas. Despite considerable variation in the results, it is possible that a large proportion of non-utilizable amino acids in heated field peas may be excreted from the pig via the urine in the form of a protein.

Two growth experiments were conducted to determine the effect of heat on the utilization of ileal-digestible lysine from field peas (Pisum sativum cultivar Dundale) fed to growing pigs. Five lysine-deficient diets (0.36 g ileal-digestible lysine/MJ digestible energy (DE)) were formulated using raw field peas, and field peas heated to either 110°, 135°, 150°, or 165° for 15 min respectively in a forced-air dehydrator. Additional diets were formulated with supplements of free lysine to verify that lysine was limiting in the diets containing the raw peas, and peas heated to 150° or 165°. The growth performance and retention of ileal-digestible lysine by pigs given the diets was determined over the 20–45 kg growth phase. Heat had a significant quadratic effect (P < 0.01) on growth rate, with responses declining from 543 g/d with pigs given the raw peas, to 407 g/d for those given the peas heated to 165°. Similarly, crude protein deposition declined in a quadratic manner (P < 0.001) from 76 to 36 g/d for pigs fed on raw peas and peas heated to 165° respectively. Retention of ileal-digestible lysine was 0.85 in the pigs given the raw field peas and declined in a quadratic manner (P < 0.001) with the application of heat to 0.48 in those pigs given the peas heated to 165°. Pigs fed on field peas heated to 165° had increased (P < 0.05) liver weights. The results indicate that heat applied to protein concentrates, even at mild temperatures, renders lysine in a form that is apparently absorbed but inefficiently utilized by the growing pig. Consequently, ileal digestibility values for lysine in heat-processed meals are unsuitable for diet formulations.

Three experiments were conducted to examine the effect of heating field peas (Pisum sativum cultivar Dundale) on (1) proximate analysis and total amino acid composition, (2) ileal and faecal digestibilities of amino acids, and (3) digestible energy content. Alternative techniques for assessing ileal and faecal digestibilities and digestible energy respectively, were also investigated. Forced-air dehydrators were used to heat field peas at temperatures of 110°, 135°, 150° or 165°. In the first experiment the apparent ileal and faecal digestibilities of amino acids and the faecal digestibility of energy in the raw and heated field peas were determined using pigs fitted with ‘T’ -shaped cannulas. In the second, apparent ileal digestibility of amino acids and the faecal digestibility of energy were determined using the direct ileal and rectal sampling technique. This involved a single collection of digesta and faeces from the digestive tract of the pig while it was anaesthetized. The faecal digestibilities of amino acids and energy were determined using total faeces collection in the third experiment. In all experiments the respective field-pea treatments comprised 400 g/kg sugar-based diets and were the only source of amino acids. Heat significantly decreased the lysine (14.6–8.7 g/kg; P < 0.001), cystine (3.2–2.6 g/kg; P < 0.01) and arginine (16.7–14.5 g/kg; P < 0.05) contents of the heated peas. The ‘reactive’ lysine content of the field peas, as measured using the Silcock technique, was decreased by 0.11 and 0.30 with the application of heat at 150° and 165° respectively. Heat treatments did not alter the ileal digestibility of most amino acids. Only aspartic acid (0.72–0.58), glutamic acid (0.80–0.65) and the basic amino acids, lysine (0.79–0.56) and arginine (0.85–0.75), showed a significant linear decrease (P < 0.05) in ileal digestibility over the heat treatments, determined using the ileal cannulation procedure. Heating significantly (P < 0.05) decreased faecal digestibility for all amino acids. Faecal digestibility was consistently greater than ileal digestibility for the raw field peas; however, this difference decreased with heat application until faecal digestibility was equal or less than ileal digestibility at the 165° treatment. Heat linearly depressed digestible energy, diet dry-matter digestibility and diet energy digestibility. Losses in lysine, cystine and arginine are likely to be due to early and advanced Maillard reactions. Considerable binding of the remaining lysine also occurred as indicated by a decline in Silcock-reactive lysine. The results indicate that the direct ileal sampling technique is a viable alternative to the cannulation procedure for amino acids, but further method development is required to decrease the variability associated with measurements. The estimation of faecal digestibility using indigestible markers and the partial faeces collection technique was as efficient as total faeces collection. In general, ileal digestibility of amino acids showed little response to heating, however, any changes that were observed were greatest for lysine. In contrast, faecal digestibility of all amino acids was greatly reduced with increasing heat application. This response appeared to be largely due to the effect of heating on microbial degradation and synthesis of amino acids in the hind-gut, rather than a reflection of the changes within the protein induced by heating. This variable response makes faecal digestibility an unreliable estimator of amino acid ileal digestibility.

Variation is inherent in any biological system and is a challenge to manage in modern pork-production businesses. In the case of the growing and finishing herd, inherent variation within a population of pigs represents a significant cost as a result of the need to select on farm to meet market specifications, poor matching of diet specifications to nutrient requirements, grading losses, higher pre-weaning mortality, and challenges associated with health management. As a consequence, any management practice that can be applied to reduce variation at the point of sale has the potential to improve the profitability and overall efficiency of a pig enterprise. The present paper considers nutritional interventions of sows during gestation, lactation and the weaning to oestrus interval to minimise inherent variation in the progeny and then pre- and post-weaning nutrition of piglets to limit further variation. Prior to birth, there are many factors that can influence variation in the birthweight and growth potential of the progeny. In gestating sows, dietary energy will not influence variation in birthweight, but supplementation with free arginine and glutamine will reduce variation in birthweight of piglets born and piglets born alive. In lactating sows, maintenance of feed intake to optimise milk production and minimise weight loss of the sow during lactation not only minimises variation in progeny weight at weaning, but enhances subsequent birthweight heterogeneity due to the influence of the sow’s metabolic status on follicle and oocyte quality. Supplementation with dextrose during the weaning to oestrus interval can also reduce variation in birthweight due to a pronounced effect on plasma glucose and insulin concentrations. Prior to weaning, light weight piglets appear to have an enhanced capacity for growth compared with their larger counterparts. To this end, split suckling has been shown to reduce weaning-weight variation, despite no effect on average growth rate or weaning weight for litters with nine piglets or more born alive. Supplemental milk before weaning has reduced variation in weaning weights, but creep feeding has proved equivocal in this regard. Post-weaning, it appears that remedial feeding strategies will do little to improve the growth potential of light-weight pigs, and while high specification diets may contribute to a slight reduction in variation at slaughter, this strategy is unlikely to be economically viable. As with many aspects of commercial pork production, it would seem that the greatest potential to reduce variation in the slaughter weight of market pigs vests with careful management of gestating and lactating sows, with some potential for dietary interventions to further reduce variation in birth and weaning weights.

The aim of this study was to investigate the performance and carcass responses of finisher boars and gilts offered a range of dietary lysine levels and three levels of dietary ractopamine hydrochloride (RAC). The study involved three experiments of 90 pigs each, totalling 270 individually penned pigs in a 2 by 5 by 3 factorial design comprising two sexes (gilts, boars), five levels of dietary lysine [0.40, 0.48, 0.56, 0.64, and 0.72 g available lysine per MJ of digestible energy (DE), respectively] and three RAC dose regimes (0, 5 and 10 mg/kg) for 28 days. An outbreak of pneumonia (Actinobaccilus pleuropneumonia) at Day 26 in Experiment 1 compromised Day 28 data; however, Day 21 data was considered suitable across all three experiments. The results indicate that 0.56 g available lysine/MJ DE is sufficient to maximise average daily gain (ADG), feed conversion ratio (FCR) and carcass weight in gilts. Control boars indicated that ADG and FCR were not limited by the lysine : energy ratios fed in this study. Increasing levels of dietary lysine linearly increased ADG (P < 0.001), improved FCR (P < 0.001) and increased carcass weight (P = 0.001). Likewise, increasing dietary RAC further improved ADG (P = 0.001), FCR (P = 0.002) and carcass weight (P = 0.075) linearly. The critical lysine levels calculated for ADG and FCR in gilts fed diets supplemented with RAC were less than required for controls. Boars had higher critical lysine levels than gilts when supplemented with dietary RAC, and increasing dietary RAC increased critical lysine levels for ADG and FCR in gilts and boars. An interaction (P = 0.016) between dietary lysine and RAC occurred for FCR, such that the response to 5 mg/kg dietary RAC diminished in diets containing 0.64 g and 0.72 g available lysine/MJ DE; however, these diets elicited a response when supplemented with 10 mg/kg RAC. Responses in ADG, FCR and carcass weight to dietary RAC were noted when dietary lysine was at or below the current recommendations for RAC diets, and it was suggested that this may have been due to reduced efficiency of lysine utilisation due to chronic disease challenge. A Sex × RAC interaction (P = 0.027) occurred for carcass P2, indicating the higher RAC dose reduced carcass P2 in boars but not in gilts. When formulating finisher pig diets between 60 and 90 kg liveweight, consideration of the lysine : energy requirements for boars and gilts is needed in order to maximise ADG, FCR and carcass characteristics. When supplementing pigs with dietary RAC, a wide range of lysine : energy levels maybe employed; however, this is dependent on RAC inclusion level and probably herd health.

Transition from gestation stalls to group-housing systems is a source of trepidation for many pork producers, given the capital cost of conversion and the challenges associated with managing sows in groups. Despite this, market imperatives in Australia have led to rapid transition in many enterprises. The cost of conversion of a 4100-sow unit from stalls to groups using low-cost retrofitting of existing breeder space (AU$150.00/sow) at relatively high densities (1.8 m2/sow) in small static groups (15–20 sows) based on floor or trough feeding with or without head bales and shoulder partitions equates to an additional cost of $3.00/piglet weaned if the level of productivity is maintained. If the number of piglets born per litter is increased by 1.04 piglets per litter, overall earnings of the herd are equal to levels achieved before the transition. This capital cost appears manageable if appropriate nutritional regimens are implemented to address individual nutritional needs of sows housed in groups and to manage aggression. Management of sow body condition during the reproductive cycle focussed on standardised gilt introduction to the breeding herd and optimisation of sow and gilt feed intake in lactation is pivotal, as it reduces the need for remedial feeding of individual sows post-weaning and during gestation. Nutritional management can also be used to reduce aggression between sows by removing impediments to feed access and by induction of satiety. Commercial implementation of these strategies confirms their relevance and demonstrates that sows can be cost-effectively managed in group-housing systems.

Dietary ractopamine increases lean tissue deposition and responses increase as dose is increased provided sufficient dietary lysine is supplied. In Australia, diets supplemented with ractopamine (RAC) are formulated with 0.56 g available lysine per MJ digestible energy. The present study was conducted to investigate the interactions between dietary RAC and lysine on growth and carcass characteristics in ad libitum fed (13.8 MJ/kg) boars and gilts. The study involved 108 individually penned pigs at 17 weeks of age (64.1 ± 0.57 kg) in a 2 by 2 by 3 factorial design, with the respective factors being sex (gilt or boar), dietary lysine (low and high, i.e. 0.56 or 0.65 g available lysine/MJ digestible energy, respectively) and dietary RAC (0, 5 or 20 mg/kg) for 28 days. Over the 28-day study duration, both lysine diets containing dietary RAC were sufficient to elicit a response in average daily gain (ADG) (+5.8%, P = 0.026) and carcass weight (3%, P = 0.045), but not in feed efficiency (FE) (P = 0.555). However, over the period of the first 7 days, there were interactions between the effects of RAC and lysine for FE (P = 0.025) and ADG (P = 0.023), with both traits being responsive only to dietary RAC containing the high lysine, which increased FE (+9.1%, P = 0.002) and ADG (+7.2%, P = 0.068). Dietary RAC improved FE in the latter stages of the study, namely Days 15–21 (+5.7%, P = 0.031) and Days 22–28 (+4.9%, P = 0.040). The high RAC diet reduced carcass P2 backfat (–16.5%, P < 0.001) and fat tissue deposition (–6.2%, P = 0.074) and high lysine tended to reduce fat tissue deposition (–13.3%, P = 0.072). A sex by lysine interaction (P = 0.043) was observed for lean tissue deposition at 28 days, such that only the high-lysine diet increased lean deposition in boars (+11%, P < 0.05) but not in gilts. Dietary RAC tended to increase lean deposition (+14.0%, P = 0.067) in the first 14 days; however, only the high RAC diet increased lean deposition (+9.6%, P < 0.05) over 28 days. In conclusion, the current recommended supplementation levels of lysine for commercial gilts and boars fed RAC may limit the response to dietary RAC if the feeding regime is for short durations and boars will not maximise their lean tissue deposition rates.

The effect of heat on the availability of lysine in field peas (Pisum sativum cultivar Dundale) was determined using the slope–ratio assay with growing pigs. The field peas were heated to 110°, 135°, 150°, or 165° for 15 min using a forced-air dehydrator. Lysine availability was significantly depressed (P < 0.05) with the application of heat, even at mild temperatures of 110°. Lysine availability values of 0.96, 0.71, 0.77, 0.56, and 0.47 were determined for the raw peas and peas heated to 110°, 135°, 150° or 165° respectively. The effect of dietary protein level on the ileal digestibility of lysine in raw field peas was determined in a second experiment to estimate true ileal digestibility. Five diets were formulated to contain 85, 105, 125, 145 and 165 g protein/kg. Increasing dietary protein from 85 to 105 g/kg resulted in a significant increase in the estimate of apparent ileal digestibility from 0.84 to 0.93. Comparisons were then able to be drawn between the ileal digestibility, availability and utilization of lysine from raw and heat-treated field peas. The results indicate that unlike ileal digestibility values, estimates of lysine availability are sensitive to heat treatment and are a close reflection of lysine utilization in heated protein concentrates. Thus, lysine availability values would be more suitable for use in diet formulations than ileal digestibility estimates when dealing with heat-processed protein concentrates.

Three experiments were conducted to examine the effect of heating field peas (Pisum sativum cultivar Dundale) on (1) proximate analysis and total amino acid composition, (2) ileal and faecal digestibilities of amino acids, and (3) digestible energy content. Alternative techniques for assessing ileal and faecal digestibilities and digestible energy respectively, were also investigated. Forced-air dehydrators were used to heat field peas at temperatures of 110 degrees, 135 degrees, 150 degrees or 165 degrees. In the first experiment the apparent ileal and faecal digestibilities of amino acids and the faecal digestibility of energy in the raw and heated field peas were determined using pigs fitted with 'T'-shaped cannulas. In the second, apparent ileal digestibility of amino acids and the faecal digestibility of energy were determined using the direct ileal and rectal sampling technique. This involved a single collection of digesta and faeces from the digestive tract of the pig while it was anaesthetized. The faecal digestibilities of amino acids and energy were determined using total faeces collection in the third experiment. In all experiments the respective field-pea treatments comprised 400 g/kg sugar-based diets and were the only source of amino acids. Heat significantly decreased the lysine (14.6-8.7 g/kg; P0.001), cystine (3.2-2.6 g/kg; P0.01) and arginine (16.7-14.5 g/kg; P0.05) contents of the heated peas. The 'reactive' lysine content of the field peas, as measured using the Silcock technique, was decreased by 0.11 and 0.30 with the application of heat at 150 degrees and 165 degrees respectively. Heat treatments did not alter the ileal digestibility of most amino acids. Only aspartic acid (0.72-0.58), glutamic acid (0.80-0.65) and the basic amino acids, lysine (0.79-0.56) and arginine (0.85-0.75), showed a significant linear decrease (P0.05) in ileal digestibility over the heat treatments, determined using the ileal cannulation procedure. Heating significantly (P0.05) decreased faecal digestibility for all amino acids. Faecal digestibility was consistently greater than ileal digestibility for the raw field peas; however, this difference decreased with heat application until faecal digestibility was equal or less than ileal digestibility at the 165 degrees treatment. Heat linearly depressed digestible energy, diet dry-matter digestibility and diet energy digestibility. Losses in lysine, cystine and arginine are likely to be due to early and advanced Maillard reactions. Considerable binding of the remaining lysine also occurred as indicated by a decline in Silcock-reactive lysine.(ABSTRACT TRUNCATED AT 400 WORDS)

Lupins are high in crude protein, cell wall materials, and gross energy but uncertainty about the bioavailability of nutrients and adverse effects on feed intake limit their use in the pig industry. Three experiments were conducted to determine the effect of lupins on retention time in the digestive tract by determining the average time it took for ingested polyethylene beads to pass through the digestive tract of pigs fed wheat-based diets containing various lupin species and fractions. In Expt 1, pigs were restrictively fed (1.8 kg/day) diets containing either predominantly wheat or predominantly wheat plus 400 g/kg peas or L. angustifolius seeds or kernels. The retention times of diets containing 400 g/kg of L. angustifolius seeds or kernels were significantly greater than those containing wheat alone (66.4 and 64.3 v. 48.8 h, P < 0.05, s.e.d. = 7.7 h), while that for the diet containing 400 g/kg peas was intermediate (55.8 h). In Expt 2 and 3, pigs were fed 1 of 6 wheat-based diets balanced for digestible energy (DE) and amino acid composition and containing either animal protein or 350 g/kg of peas, and L. angustifolius seeds or kernels, or L. albus seeds and kernels. Pigs were restrictively fed (1.5 kg/day) for Expt 2 or fed ad libitum for Expt 3. The mean retention time of the L. albus diets was greater than the other diets in both experiments. Feed intake and daily gain were reduced in pigs fed diets containing L. albus. Despite having lower feed intakes, pigs fed diets containing L. albus had more digesta in the stomach and small intestine at slaughter than the pigs consuming the diets not containing lupins. Appropriate physical treatment or enzymatic supplementation of L. albus diets may alleviate some of the feed intake problems.

In experiment 1, 4 treatments were prepared consisting of a mixture of chopped wheat straw in different proportions, a fixed proportion of poultry litter and 0, 15, 30 and 45% citrus pulp on a dry matter basis. The mixtures were ensiled for 60 days at room temperature in polythene bags. Ensiling (time effect) resulted in an increase (P0.05) in dry matter intake between diets containing 0, 76 and 167 g/kg citrus pulp when the intake was expressed on the basis of metabolic body weight. However, there was a decrease (P

In a 4 2 factorial design, mixtures of wheat straw, poultry litter and citrus pulp with 0 and 5% molasses [T1 (75:25:0), T2 (60:25:15), T3 (45:25:30), and T4 (30:25:45)] were ensiled for a period of 60 days in 20 L laboratory silos. Inclusion of 5% molasses had no significant (P>0.05) effect on pH, neutral detergent fibre, acid detergent fibre, acid detergent lignin contents and in vitro organic matter (OM) degradability. However, molasses decreased (P

This paper reviews the carbohydrate, protein, lipid, anti-nutritional, and physical characteristics ofgrains that determine the variability in their nutritional quality for ruminant animals. The amount, rate, and extent of starch fermentation in the rumen have been the subject of many studies, with large variation found between and within grain species. Electron microscopy scanning techniques have shown that the protein matrix limits the microbial colonisation of starch granules in some grain species, whereas in others it may be the structural carbohydrates that affect colonisation. The composition of the different fibre fractions of grains and their interaction with non-fibre carbohydrates requires investigation, since it has been shown that non-starchpolysaccharides, including neutral detergent fibre and acid detergent fibre, may not be specific enough to predict animal response to grain. Fermentation patterns of the non-starch polysaccharide components of legumes are also poorly understood and hence require further investigation. Different varieties of grain and different seasonal conditions show variation in the protein fractions of the kernel. Since these fractions display different solubility and degradation rates in the rumen, rumen solubility values cannot be generalised for grains. The variability in solubility caused by rumen flow rate and pH is a further complication. Finally, the lipid content of grains varies greatly, with high-oil grains potentially contributing to the energy level of the diet, but possibly negatively affecting rumen fermentation. Due to the degree of variability of characteristics discussed in this review, it is clear that the nutritional quality of grains cannot be assessed in a single rapid assay.

Two experiments were conducted to determine apparent ileal digestibility of amino acids (AIDAA) and nitrogen (AIDN) in cottonseed meal (CSM) and soyabean meal (SBM) fed to growing pigs. In the first experiment, twenty-four male pigs (37·3 (SE 2·7) kg) were individually penned and randomized to either CSM or SBM diets. The diets contained 40% of the protein meal (either CSM or SBM) in a wheat starch-sucrose (1:1, w/w) base containing vitamins and minerals, and Cr2O3 as an indigestible marker. Pigs were acclimated to the experimental diets over a 3d period and on day 4 through to day 14 were offered 1800g/d of the diet. Diets were offered in three meals/d from day 4 to day 11 and in eight meals/d from day 12 to day 13. After the eighth hourly-meal on day 14, twelve pigs were anaesthetized with halothane while the remaining twelve pigs were CO2-stunned and processed using commercial slaughter procedures. Ileal digesta were collected from a 1500 mm portion of the terminal ileum of each pig and subsequently analysed for amino acids, N, organic matter and Cr. Results indicated that AIDAA of CSM and SBM were lower when digesta were collected following CO2-stunning than when digesta were obtained under halothane anaesthesia. Consistently, AIDN in CSM (0·51 v. 0·56) and SBM (0·55 v. 0-71) were lower (P 2-stunned pigs than in halothane-anaesthetized pigs. Furthermore, when digesta collection was conducted under halothane anaesthesia, AIDN of CSM was lower (P < 0·001) than that of SBM. In the second experiment, six male pigs (45 (SE 2·6) kg) were fitted with T-piece cannulas implanted in the terminal ileum, housed individually in metabolism cages, and randomly allocated to either CSM or SBM diets in a single reversal arrangement. Ileal digesta were collected for AIDAA and AIDN determination. Although statistical comparisons could not be made between the two experiments, the AIDAA and AIDN data obtained via cannulated pigs were similar to those values obtained using the halothane-anaesthesia method. Overall, the CO2-stunning method is not recommended for studies of amino acid or nitrogen ileal digestibilities, but may be useful for the study of other dietary constituents.