Reductive acetogenesis is an alternative to methanogenesis for removing hydrogen produced during enteric fermentation. In Australia, kangaroos have evolved an enlarged forestomach analogous to the rumen of sheep and cattle. However, unlike sheep and cattle, kangaroos produce very little methane from enteric fermentation. From samples of gut contents from five eastern grey and three red kangaroos, we were not able to detect methanogens using a PCR protocol, but did detect the formyltetrahydrofolate synthetase (FTHFS) gene (likely to be used for reductive acetogenesis) in all animals. Isolations to recover acetogens resulted in two different classes of hydrogen consuming bacteria being isolated. The first class consisted of acetogens that possessed the FTHFS gene, which except for Clostridium glycolicum, were not closely related to any previously cultured bacteria. The second class were not acetogens but consisted of enterobacteria (Escherichia coli and Shigella) that did not possess FTHFS genes but did utilise hydrogen and produce acetate. Enumeration of the acetogens containing the FTHFS gene by real-time PCR indicated that bacteria of the taxa designated YE257 were common to all the kangaroos whereas YE266/YE273 were only detected in eastern grey kangaroos. When present, both species occurred at densities above ×106 cell equivalents per mL. C. glycolicum was not detected in the kangaroos and, unlike YE257 and YE266/273, is unlikely to play a major role in reductive acetogenesis in the foregut of kangaroos.
Remote drafting technology now available for sheep makes possible targeted supplementation of individuals within a grazing flock. This system was evaluated by using 68 Merino wethers grazing dry-season, native Mitchell grass pasture (predominantly Astrebla spp.) as a group and receiving access to lupin grain through a remote drafter 0, 1, 2, 4 or 7 days/week for 8 weeks. The sole paddock watering point was separately fenced and access was via a one-way flow gate. Sheep exited the watering point through a remote drafter operated by solar power and were drafted by radio frequency identification (RFID) tag, according to treatment, either back into the paddock or into a common supplement yard where lupins were provided ad libitum in a self-feeder. Sheep were drafted into the supplement yard on only their first time through the drafter during the prescribed 24-h period and exited the supplement yard via one-way flow gates in their own time. The remote drafter operated with a high accuracy, with only 2.1% incorrect drafts recorded during the experimental period out of a total of 7027 sheep passes through the remote drafter. The actual number of accesses to supplement for each treatment group, in order, were generally less than that intended, i.e. 0.02, 0.69, 1.98, 3.35 and 6.04 days/week. Deviations from the intended number of accesses to supplement were mainly due to sheep not coming through to water on their allocated day of treatment access, although some instances were due to incorrect drafts. There was a non-linear response in growth rate to increased frequency of access to lupins with the growth rate response plateauing at similar to 3 actual accesses per week, corresponding to a growth rate of 72.5 g/head. day. This experiment has demonstrated the application of the remote drafting supplementation system for the first time under grazing conditions and with the drafter operated completely from solar power. The experiment demonstrates a growth response to increasing frequency of access to supplement and provides a starting point with which to begin to develop feeding strategies to achieve sheep weight-change targets.
The incorporation of sown pastures as short-term rotations into the cropping systems of northern Australia has been slow. The inherent chemical fertility and physical stability of the predominant vertisol soils across the region enabled farmers to grow crops for decades without nitrogen fertiliser, and precluded the evolution of a crop–pasture rotation culture. However, as less fertile and less physically stable soils were cropped for extended periods, farmers began to use contemporary farming and sown pasture technologies to rebuild and maintain their soils. This has typically involved sowing long-term grass and grass–legume pastures on the more marginal cropping soils of the region.
In partnership with the catchment management authority, the Queensland Murray–Darling Committee (QMDC) and Landcare, a pasture extension process using the LeyGrain™ package was implemented in 2006 within two Grain & Graze projects in the Maranoa-Balonne and Border Rivers catchments in southern inland Queensland. The specific objectives were to increase the area sown to high quality pasture and to gain production and environmental benefits (particularly groundcover) through improving the skills of producers in pasture species selection, their understanding and management of risk during pasture establishment, and in managing pastures and the feed base better. The catalyst for increasing pasture sowings was a QMDC subsidy scheme for increasing groundcover on old cropping land. In recognising a need to enhance pasture knowledge and skills to implement this scheme, the QMDC and Landcare producer groups sought the involvement of, and set specific targets for, the LeyGrain workshop process. This is a highly interactive action learning process that built on the existing knowledge and skills of the producers.
Thirty-four workshops were held with more than 200 producers in 26 existing groups and with private agronomists. An evaluation process assessed the impact of the workshops on the learning and skill development by participants, their commitment to practice change, and their future intent to sow pastures.
The results across both project catchments were highly correlated. There was strong agreement by producers (>90%) that the workshops had improved knowledge and skills regarding the adaptation of pasture species to soils and climates, enabling a better selection at the paddock level. Additional strong impacts were in changing the attitudes of producers to all aspects of pasture establishment, and the relative species composition of mixtures.
Producers made a strong commitment to practice change, particularly in managing pasture as a specialist crop at establishment to minimise risk, and in the better selection and management of improved pasture species (particularly legumes and the use of fertiliser). Producers have made a commitment to increase pasture sowings by 80% in the next 5 years, with fourteen producers in one group alone having committed to sow an additional 4893 ha of pasture in 2007–08 under the QMDC subsidy scheme.
The success of the project was attributed to the partnership between QMDC and Landcare groups who set individual workshop targets with LeyGrain presenters, the interactive engagement processes within the workshops themselves, and the follow-up provided by the LeyGrain team for on-farm activities.
The present review identifies various constraints relating to poor adoption of ley-pastures in south-west Queensland, and suggests changes in research, development and extension efforts for improved adoption. The constraints include biophysical, economic and social constraints.
In terms of biophysical constraints, first, shallower soil profiles with subsoil constraints (salt and sodicity), unpredictable rainfall, drier conditions with higher soil temperature and evaporative demand in summer, and frost and subzero temperature in winter, frequently result in a failure of established, or establishing, pastures. Second, there are limited options for legumes in a ley-pasture, with the legumes currently being mostly winter-active legumes such as lucerne and medics. Winter-active legumes are ineffective in improving soil conditions in a region with summer-dominant rainfall. Third, most grain growers are reluctant to include grasses in their ley-pasture mix, which can be uneconomical for various reasons, including nitrogen immobilisation, carryover of cereal diseases and depressed yields of the following cereal crops. Fourth, a severe depletion of soil water following perennial ley-pastures (grass + legumes or lucerne) can reduce the yields of subsequent crops for several seasons, and the practice of longer fallows to increase soil water storage may be uneconomical and damaging to the environment.
Economic assessments of integrating medium- to long-term ley-pastures into cropping regions are generally less attractive because of reduced capital flow, increased capital investment, economic loss associated with establishment and termination phases of ley-pastures, and lost opportunities for cropping in a favourable season. Income from livestock on ley-pastures and soil productivity gains to subsequent crops in rotation may not be comparable to cropping when grain prices are high. However, the economic benefits of ley-pastures may be underestimated, because of unaccounted environmental benefits such as enhanced water use, and reduced soil erosion from summer-dominant rainfall, and therefore, this requires further investigation.
In terms of social constraints, the risk of poor and unreliable establishment and persistence, uncertainties in economic and environmental benefits, the complicated process of changing from crop to ley-pastures and vice versa, and the additional labour and management requirements of livestock, present growers socially unattractive and complex decision-making processes for considering adoption of an existing medium- to long-term ley-pasture technology.
It is essential that research, development and extension efforts should consider that new ley-pasture options, such as incorporation of a short-term summer forage legume, need to be less risky in establishment, productive in a region with prevailing biophysical constraints, economically viable, less complex and highly flexible in the change-over processes, and socially attractive to growers for adoption in south-west Queensland.
Ongoing pressure to minimise costs of production, growing markets for low residue and organic wool and meat, resistance to chemicals in louse populations, and the deregistration of diazinon for dipping and jetting have contributed to a move away from routine annual application of lousicides to more integrated approaches to controlling lice. Advances including improved methods for monitoring and detection of lice, an expanded range of louse control products and the availability of a web-accessible suite of decision support tools for wool growers (LiceBoss (TM)) will aid this transition. Possibilities for the future include an on-farm detection test and non-chemical control methods. The design and extension of well-constructed resistance management programs to preserve the effectiveness of recently available new product groups should be a priority.
This study examined the effectiveness of leuprolide, a gonadotrophin-releasing hormone agonist, in suppressing rut-associated events in farmed male red deer. In mid-January (approximately 6 weeks before the rut period in the southern hemisphere) adult red deer (Cervus elaphus scoticus) stags that had been allocated to three groups (n = 10 per group) received leuprolide, administered subcutaneously in a 90-day release formulation, at zero (control), low (22.5 mg) or high (45 mg) doses. Following treatment with leuprolide there was evidence of suppression of mean plasma luteinising hormone concentration that was significant (P < 0.05) at 9 weeks. Mean plasma testosterone concentration of all three groups rose following treatment, then declined prematurely in the low- and high-dose leuprolide-treated groups, so that it was significantly (P < 0.05) suppressed (0.66 ± 0.29 and 2.0 ± 0.88 ng mL⁻¹, low and high dose respectively) in early April when the peak value (9.0 ± 1.94 ng mL⁻¹) was recorded from control stags. A reduction in mean liveweight occurred in all three groups through February-April and this did not differ among treatments. However, a corresponding reduction in mean body condition score was greater in the control stags (P < 0.05). There was little effect of leuprolide treatment on aggressive behaviours, but it lowered roaring frequency in the latter period of the rut. The results indicate that this gonadotrophin-releasing hormone agonist has potential for application in the deer farming industry to suppress undesirable effects of the rut.
Spirulina, a freshwater microalgae, has previously been shown to increase the efficiency of microbial protein production in cattle fed hay with a low crude protein content. The present study was carried out to determine the effect of increasing the concentration of Spirulina in the drinking water on the intake of water and the amount of water containing Spirulina bypassing the rumen of cattle. Five rumen-cannulated steers were given a fixed amount of pangola grass hay (14 g DM/kg W.day(-1)) and water containing 0, 1, 2, 2.7 and 3.5% (w/w) Spirulina in an incomplete Latin square design. Water intake by the control steers (0% Spirulina) was 29.7 and 49.3 g/kgW for the first drinking event after it was made available and over 24 h, respectively. For steers receiving the algae, intake of water plus Spirulina increased linearly (P < 0.01) from 42.7 to 60.2 g/kgWduring the. first drinking event, as the concentration of Spirulina in the drinking water increased, but over 24 h was not affected by Spirulina concentration and averaged 74.4 g/kg W. The bypass of water through the rumen, as determined using chromium-EDTA as a marker, averaged 20.5 +/- 1.2% and was not affected by the concentration of Spirulina in the drinking water. Increasing inclusion of Spirulina was associated with a decrease in rumen pH, an increase in urea concentration in blood serum, and an increase in ammonia-N concentration, propionate and branched-chain fatty acids, and a decrease in butyrate proportions in rumen fluid. Spirulina inclusion in the drinking water increased water intake and may provide a potential safe and inexpensive alternative to urea for extensively grazed ruminants.
The influence of increasing dietary concentrations of copper (Cu), together with low or high inclusion levels of zinc (Zn), on performance, faecal mineral concentrations and the mineral status of the body was examined in 216 Large White × Landrace pigs (initial weight 27 kg, final weight 107 kg). The base diets were supplemented with combinations of 0, 10, 30 or 50 mg/kg Cu and 40 or 80 mg/kg Zn in the proteinate amino acid chelate form (organic), according to a factorial arrangement of treatments. A control treatment containing levels of Cu and Zn similar to the high organic treatment in the form of sulfate (inorganic) was also included. Blood and faecal samples were collected on Days 21 and 49 of the experiment and tissue samples immediately after slaughter. Across the entire growing and finishing phases, no significant treatment differences (P > 0.05) occurred in pig daily gain or feed intake, although feed conversion ratio was improved (P < 0.05) by the inclusion of proteinate amino acid chelate. Copper and Zn concentrations in faeces were in direct proportion to their inclusion level in the diet. Blood and tissue mineral concentrations were within normal physiological ranges in all treatments. Results showed that reducing Cu and Zn in grower-finisher diets from 50 to 0 mg/kg Cu and from 80 to 40 mg/kg Zn reduced faecal Cu and Zn concentrations by 90 and 40%, respectively, without compromising pig growth. However, when Cu was supplemented at 0 mg/kg, storage of Cu in the liver approached marginal levels, suggesting that some added dietary Cu is needed in grower-finisher diets, especially for pigs reared in commercial conditions.
Steer liveweight gains were measured in an extensive grazing study conducted in a Heteropogon contortus (black speargrass) pasture in central Queensland between 1988 and 2001. Treatments included a range of stocking rates in native pastures, legume-oversown native pasture and animal diet supplement/spring-burning pastures. Seasonal rainfall throughout this study was below the long-term mean. Mean annual pasture utilisation ranged from 13 to 61%. Annual liveweight gains per head in native pasture were highly variable among years and ranged from a low of 43 kg/steer at 2 ha/steer to a high of 182 kg/steer at 8 ha/steer. Annual liveweight gains were consistently highest at light stocking and decreased with increasing stocking rate. Annual liveweight gain per hectare increased linearly with stocking rate. These stocking rate trends were also evident in legume-oversown pastures although both the intercept and slope of the regressions for legume-oversown pastures were higher than that for native pasture. The highest annual liveweight gain for legume-oversown pasture was 221 kg/steer at 4 ha/steer. After 13 years, annual liveweight gain per unit area occurred at the heaviest stocking rate despite deleterious changes in the pasture. Across all years, the annual liveweight advantage for legume-oversown pastures was 37 kg/steer. Compared with native pasture, changes in annual liveweight gain with burning were variable. It was concluded that cattle productivity is sustainable when stocking rates are maintained at 4 ha/steer or lighter (equivalent to a utilisation rate around 30%). Although steer liveweight gain occurred at all stocking rates and economic returns were highest at heaviest stocking rates, stocking rates heavier than 4 ha/steer are unsustainable because of their long-term impact on pasture productivity.
The diet selected in autumn by steers fistulated at the oesophageous was studied in a subset of treatments in an extensive grazing study conducted in a Heteropogon contortus pasture in central Queensland between 1988 and 2001. These treatments were a factorial array of three stocking rates (4, 3 and 2 ha/steer) and three pasture types (native pasture, legume-oversown native pasture and animal diet supplement/spring-burning native pasture). Seasonal rainfall throughout this study was below the long-term mean and mean annual pasture utilisation ranged from 30 to 61%. Steers consistently selected H. contortus with levels decreasing from 47 to 18% of the diet as stocking rate increased from 4 ha/steer to 2 ha/steer. Stylosanthes scabra cv. Seca was always selected in legume-oversown pastures with diet composition varying from 35 to 66% despite its plant density increasing from 7 to 65 plants/m(2) and pasture composition from 20 to 50%. Steers also selected a diet containing Chrysopogon fallax, forbs and sedges in higher proportions than they were present in the pasture. Greater availability of the intermediate grasses Chloris divaricata and Eragrostis spp. was associated with increased stocking rates. Bothriochloa bladhii was seldom selected in the diet, especially when other palatable species were present in the pasture, despite B. bladhii often being the major contributor to total pasture yield. It was concluded that a stocking rate of 4 ha/steer will maintain the availability of H. contortus in the pasture.
Cocoa-pods, a by-product of the cocoa industry, could potentially be used as a feed resource for ruminants in eastern Indonesia. However, little is known regarding the optimal amount to be included in the diet or the effect of treatment with Aspergillus niger on cocoa-pod quality. In this experiment the effect of rate of inclusion (0 or 10 gDM/kg liveweight. day or ad libitum) of A. niger-treated or untreated cocoa-pods in the diet on intake and liveweight gain of Bali cattle (Bos sondaicus) was investigated. Ad libitum intake of cocoa-pods was greater when they were treated with A. niger (17.1 +/- 0.07 g DM/kg liveweight. day; mean +/- s.e.m.) compared with untreated cocoa-pods (13.9 +/- 0.19 g DM/kg liveweight. day) when offered as the sole component of the diet. The digestibility of A. niger-treated cocoa-pods (448.9 +/- 23.7 g/kg) was not different to untreated cocoa-pods (422.9 +/- 13.9 g/kg) when fed ad libitum, which was lower than native grass (527.2 +/- 10.7 g/kg). Animals offered A. niger-treated cocoa-pods lost less liveweight than animals offered untreated cocoa-pods when offered ad libitum (-0.104 +/- 0.02 and -0.280 +/- 0.02 kg/day, respectively), and grew faster when included in the diet at 10 g DM/kg liveweight. day (0.233 +/- 0.02 and 0.129 +/- 0.02 kg/day, respectively). In conclusion, in areas where cocoa plantations exist, cocoa-pods may be a useful feed resource for ruminants when fed at low levels of inclusion in the diet. The treatment of cocoa-pods with A. niger will result in increased liveweight gain. However, it is unlikely such treatments will be adopted by small-holder farmers due to the increased requirements for inputs, such as time, labour, funds, equipment, and technical skills.
Farmlets, each of 20 cows, were established to field test five milk production systems and provide a learning platform for farmers and researchers in a subtropical environment. The systems were developed through desktop modelling and industry consultation in response to the need for substantial increases in farm milk production following deregulation of the industry. Four of the systems were based on grazing and the continued use of existing farmland resource bases, whereas the fifth comprised a feedlot and associated forage base developed as a greenfield site. The field evaluation was conducted over 4 years under more adverse environmental conditions than anticipated with below average rainfall and restrictions on irrigation. For the grazed systems, mean annual milk yield per cow ranged from 6330 kg/year (1.9 cows/ha) for a herd based on rain-grown tropical pastures to 7617 kg/year (3.0 cows/ha) where animals were based on temperate and tropical irrigated forages. For the feedlot herd, production of 9460 kg/cow.year (4.3 cows/ha of forage base) was achieved. For all herds, the level of production achieved required annual inputs of concentrates of similar to 3 t DM/animal and purchased conserved fodder from 0.3 to 1.5 t DM/animal. This level of supplementary feeding made a major contribution to total farm nutrient inputs, contributing 50% or more of the nitrogen, phosphorus and potassium entering the farming system, and presents challenges to the management of manure and urine that results from the higher stocking rates enabled. Mean annual milk production for the five systems ranged from 88 to 105% of that predicted by the desktop modelling. This level of agreement for the grazed systems was achieved with minimal overall change in predicted feed inputs; however, the feedlot system required a substantial increase in inputs over those predicted. Reproductive performance for all systems was poorer than anticipated, particularly over the summer mating period. We conclude that the desktop model, developed as a rapid response to assist farmers modify their current farming systems, provided a reasonable prediction of inputs required and milk production. Further model development would need to consider more closely climate variability, the limitations summer temperatures place on reproductive success and the feed requirements of feedlot herds.
To study the genetic basis of tick burden and milk production and their interrelationship, we collected a sample of 1961 cattle with multiple tick counts from northern Australia of which 973 had dairy production data in the Australian Dairy Herd Information Service database. We calculated heritabilities, genetic and phenotypic correlations for these traits and showed a negative relationship between tick counts and milk and milk component yield. Tests of polymorphisms of four genes associated with milk yield, ABCG2, DGAT1, GHR and PRLR, showed no statistically significant effect on tick burden but highly significant associations to milk component yield in these data and we confirmed separate effects for GHR and PRLR on bovine chromosome 20. To begin to identify some of the molecular genetic bases for these traits, we genotyped a sample of 189 of these cattle for 7397 single nucleotide polymorphisms in a genome-wide association study. Although the allele effects for adjusted milk fat and protein yield were highly correlated (r = 0.66), the correlations of allele effects of these milk component yields and tick burden were small (|r| <= 0.10). These results agree in general with the phenotypic correlations between tick counts and milk component yield and suggest that selection on markers for tick burden or milk component yield may have no undesirable effect on the other trait.
A total of 2115 heifers from two tropical genotypes (1007 Brahman and 1108 Tropical Composite) raised in four locations in northern Australia were ovarian-scanned every 4-6 weeks to determine the age at the first-observed corpus luteum (CL) and this was used to de. ne the age at puberty for each heifer. Other traits recorded at each time of ovarian scanning were liveweight, fat depths and body condition score. Reproductive tract size was measured close to the start of the first joining period. Results showed significant effects of location and birth month on the age at first CL and associated puberty traits. Genotypes did not differ significantly for the age or weight at first CL; however, Brahman were fatter at first CL and had a small reproductive tract size compared with that of Tropical Composite. Genetic analyses estimated the age at first CL to be moderately to highly heritable for Brahman (0.57) and Tropical Composite (0.52). The associated traits were also moderately heritable, except for reproductive tract size in Brahmans (0.03) and for Tropical Composite, the presence of an observed CL on the scanning day closest to the start of joining (0.07). Genetic correlations among puberty traits were mostly moderate to high and generally larger in magnitude for Brahman than for Tropical Composite. Genetic correlations between the age at CL and heifer- and steer-production traits showed important genotype differences. For Tropical Composite, the age at CL was negatively correlated with the heifer growth rate in their first postweaning wet season (-0.40) and carcass marbling score (-0.49), but was positively correlated with carcass P8 fat depth (0.43). For Brahman, the age at CL was moderately negatively genetically correlated with heifer measures of bodyweight, fatness, body condition score and IGF-I, in both their first postweaning wet and second dry seasons, but was positively correlated with the dry-season growth rate. For Brahman, genetic correlations between the age at CL and steer traits showed possible antagonisms with feedlot residual feed intake (-0.60) and meat colour (0.73). Selection can be used to change the heifer age at puberty in both genotypes, with few major antagonisms with steer- and heifer- production traits.
The aims of this study were to: (i) determine the chemical composition of 11 samples of crude glycerol collected from seven Australian biodiesel manufacturers; and (ii) examine the effects of increasing levels of crude glycerol fed to growing-finishing pigs on performance, plasma metabolites and meat quality at slaughter. Chemical composition of crude glycerol samples varied considerably; glycerol content ranged between 38 and 96%, with some samples containing up to 29% ash and 14% methanol. One of these samples (76.1% glycerol, 1.83% methanol) was then fed to 64 female pigs (50.9 ± 5.55 kg; mean ± s.d.) allocated to one of five dietary treatments (0, 4, 8, 12 and 16% crude glycerol) until they reached 105 kg liveweight. There were no statistical differences in performance indices with increasing levels of added glycerol, although there was an unexpectedly high variation between treatments. Blood glycerol levels were unaffected by diet in week two of the experiment, but increased linearly (P < 0.001) with increasing levels of dietary glycerol before slaughter. The inclusion of crude glycerol did not influence any meat quality parameters at slaughter (P > 0.05). Diets containing added crude glycerol were less dusty after mixing, but diets that contained 8, 12 and 16% glycerol all formed a firm aggregate within 24 h of mixing that presented some feeding difficulties. This might restrict inclusion of glycerol in mash diets to dietary levels less than 8%. Furthermore, levels of residues such as methanol and ash should be monitored to prevent excessive amounts of these compounds in pig diets.
The variation in liveweight gain in grazing beef cattle as influenced by pasture type, season and year effects has important economic implications for mixed crop-livestock systems and the ability to better predict such variation would benefit beef producers by providing a guide for decision making. To identify key determinants of liveweight change of Brahman-cross steers grazing subtropical pastures, measurements of pasture quality and quantity, and diet quality in parallel with liveweight were made over two consecutive grazing seasons ( 48 and 46 weeks, respectively), on mixed Clitoria ternatea/grass, Stylosanthes seabrana/grass and grass swards (grass being a mixture of Bothriochloa insculpta cv. Bisset, Dichanthium sericeum and Panicum maximum var. trichoglume cv. Petrie). Steers grazing the legume-based pastures had the highest growth rate and gained between 64 and 142 kg more than those grazing the grass pastures in under 12 months. Using an exponential model, green leaf mass, green leaf %, adjusted green leaf % (adjusted for inedible woody legume stems), faecal near infrared reflectance spectroscopy predictions of diet crude protein and diet dry matter digestibility, accounted for 77, 74, 80, 63 and 60%, respectively, of the variation in daily weight gain when data were pooled across pasture types and grazing seasons. The standard error of the regressions indicated that 95% prediction intervals were large (+/- 0.42-0.64 kg/head.day) suggesting that derived regression relationships have limited practical application for accurately estimating growth rate. In this study, animal factors, especially compensatory growth effects, appeared to have a major influence on growth rate in relation to pasture and diet attributes. It was concluded that predictions of growth rate based only on pasture or diet attributes are unlikely to be accurate or reliable. Nevertheless, key pasture attributes such as green leaf mass and green leaf% provide a robust indication of what proportion of the potential growth rate of the grazing animals can be achieved.
The potential of beef producers to profitably produce 500-kg steers at 2.5 years of age in northern Australia's dry tropics to meet specifications of high-value markets, using a high-input management (HIM) system was examined. HIM included targeted high levels of fortified molasses supplementation, short seasonal mating and the use of growth promotants. Using herds of 300-400 females plus steer progeny at three sites, HIM was compared at a business level to prevailing best-practice, strategic low-input management (SLIM) in which there is a relatively low usage of energy concentrates to supplement pasture intake. The data presented for each breeding-age cohort within management system at each site includes: annual pregnancy rates (range: 14-99%), time of conception, mortalities (range: 0-10%), progeny losses between confirmed pregnancy and weaning (range: 0-29%), and weaning rates (range: 14-92%) over the 2-year observation. Annual changes in weight and relative net worth were calculated for all breeding and non-breeding cohorts. Reasons for outcomes are discussed. Compared with SLIM herds, both weaning weights and annual growth were >= 30 kg higher, enabling 86-100% of HIM steers to exceed 500 kg at 2.5 years of age. Very few contemporary SLIM steers reached this target. HIM was most profitably applied to steers. Where HIM was able to achieve high pregnancy rates in yearlings, its application was recommended in females. Well managed, appropriate HIM systems increased profits by around $15/adult equivalent at prevailing beef and supplement prices. However, a 20% supplement price rise without a commensurate increase in values for young slaughter steers would generally eliminate this advantage. This study demonstrated the complexity of pro. table application of research outcomes to commercial business, even when component research suggests that specific strategies may increase growth and reproductive efficiency and/or be more pro. table. Because of the higher level of management required, higher costs and returns, and higher susceptibility to market changes and disease, HIM systems should only be applied after SLIM systems are well developed. To increase profitability, any strategy must ultimately either increase steer growth and sale values and/or enable a shift to high pregnancy rates in yearling heifers.
This paper describes the development of a model, based on Bayesian networks, to estimate the likelihood that sheep flocks are infested with lice at shearing and to assist farm managers or advisers to assess whether or not to apply a lousicide treatment. The risk of lice comes from three main sources: (i) lice may have been present at the previous shearing and not eradicated; (ii) lice may have been introduced with purchased sheep; and (iii) lice may have entered with strays. A Bayesian network is used to assess the probability of each of these events independently and combine them for an overall assessment. Rubbing is a common indicator of lice but there are other causes too. If rubbing has been observed, an additional Bayesian network is used to assess the probability that lice are the cause. The presence or absence of rubbing and its possible cause are combined with these networks to improve the overall risk assessment.
The genetics of heifer performance in tropical 'wet' and 'dry' seasons, and relationships with steer performance, were studied in Brahman (BRAH) and Tropical Composite (TCOMP) (50% Bos indicus, African Sanga or other tropically adapted Bos taurus; 50% non-tropically adapted Bos taurus) cattle of northern Australia. Data were from 2159 heifers (1027 BRAH, 1132 TCOMP), representing 54 BRAH and 51 TCOMP sires. Heifers were assessed after post-weaning 'wet' (ENDWET) and 'dry' (ENDDRY) seasons. Steers were assessed post-weaning, at feedlot entry, over a 70-day feed test, and after similar to 120-day finishing. Measures studied in both heifers and steers were liveweight (LWT), scanned rump fat, rib fat and M. longissimus area (SEMA), body condition score (CS), hip height (HH), serum insulin-like growth factor-I concentration (IGF-I), and average daily gains (ADG). Additional steer measures were scanned intra-muscular fat%, flight time, and daily (DFI) and residual feed intake (RFI). Uni- and bivariate analyses were conducted for combined genotypes and for individual genotypes. Genotype means were predicted for a subset of data involving 34 BRAH and 26 TCOMP sires. A meta-analysis of genetic correlation estimates examined how these were related to the difference between measurement environments for specific traits. There were genotype differences at the level of means, variances and genetic correlations. BRAH heifers were significantly (P < 0.05) faster-growing in the 'wet' season, slower-growing in the 'dry' season, lighter at ENDDRY, and taller and fatter with greater CS and IGF-I at both ENDWET and ENDDRY. Heritabilities were generally in the 20 to 60% range for both genotypes. Phenotypic and genetic variances, and genetic correlations, were commonly lower for BRAH. Differences were often explained by the long period of tropical adaptation of B. indicus. Genetic correlations were high between corresponding measures at ENDWET and ENDDRY, positive between fat and muscle measures in TCOMP but negative in BRAH (mean of 13 estimates 0.50 and -0.19, respectively), and approximately zero between steer feedlot ADG and heifer ADG in BRAH. Numerous genetic correlations between heifers and steers differed substantially from unity, especially in BRAH, suggesting there may be scope to select differently in the sexes where that would aid the differing roles of heifers and steers in production. Genetic correlations declined as measurement environments became more different, the rates of decline (environment sensitivity) sometimes differing with genotype. Similar measures (LWT, HH and ADG; IGF-I at ENDWET in TCOMP) were genetically correlated with steer DFI in heifers as in steers. Heifer SEMA was genetically correlated with steer feedlot RFI in BRAH (0.75 +/- 0.27 at ENDWET, 0.66 +/- 0.24 at ENDDRY). Selection to reduce steer RFI would reduce SEMA in BRAH heifers but otherwise have only small effects on heifers before their first joining.
Feed intake, rumen function, microbial protein (MCP) production and the efficiency of MCP production were determined in steers fed four different forage hays varying markedly in crude protein content. Low quality tropical forage (speargrass and Mitchell grass) hays had lower crude protein content, higher neutral detergent fibre content and lower digestibility than a medium quality tropical forage (pangola grass) hay and a temperate forage (ryegrass) hay. Steers fed speargrass and Mitchell grass hays had lower MCP production (80 and 170 g MCP/day, respectively) and efficiency of MCP production [78 and 79 g MCP/kg digestible organic matter (DOM), respectively] than steers fed pangola grass (328 g MCP/day; 102 g MCP/kg DOM) and ryegrass (627 g MCP/day; 135 g MCP/kg DOM) hays, which was directly related to the supply of DOM and rumen degradable protein. Intake was greatest for ryegrass hay, followed by pangola grass, Mitchell grass and speargrass hays [17.6, 15.6, 10.1 and 5.5 g DM/kg W.day, respectively]. The retention time of DM in the rumen was 72.1, 47.7, 28.6 and 19.1 h for speargrass, Mitchell grass, pangola grass and ryegrass hays, respectively, with a similar trend apparent for the retention time of neutral detergent fibre, lignin, chromium-EDTA and ytterbium labelled digesta. The difference in the protein : energy ratio of absorbed substrates (measured as efficiency of MCP production) did not appear to account for all the differences in intake, nor did a purely physical mechanism.
The methods of single nucleotide polymorphism (SNP) identification can lead to ascertainment bias, which will affect population genetic analyses based on those data. In livestock species, the methods of SNP identification through genome sequencing are likely to suffer from this ascertainment bias. In the present study, a subset of data from the Bovine HapMap Project was re-analysed to quantify the effects of ascertainment bias on a range of common analyses and statistics. Data from 189 animals of the zebu breeds Brahman, Nelore and Gir, taurine beef Angus, Limousin and Hereford and taurine dairy Holstein, Jersey and Brown Swiss were analysed. There were 141 SNPs each of Angus, Brahman and Holstein origin, giving a total of 423 SNPs organised in 141 triplets. Each triplet consisted of one SNP of each breed, separated on average by 0.75 Mb within each triplet and where triplets were separated by 14.96 Mb to ensure that each triplet was unaffected by linkage disequilibrium. The minor allele frequency distribution, estimates of the F-statistic, FST, the partitioning of variance and population substructure were relatively unaffected by breed of origin of the SNPs. Estimates of heterozygosity were significantly affected by breed of origin of the SNPs. The clustering of animals of closely related breeds varied in the principal component analyses (PCA). However, in the PCA the effect of breed of origin of 141 SNPs was similar to the effect of using different panels of 141 SNPs of all three breeds, so the differences found in the PCA may not be all due to bias by the origin of the SNPs. Based on these results, analyses that depend on FST, including signatures of selection, gene flow and effective population size are unlikely to be strongly affected by SNP origin. Analyses that partition genetic variance and some analyses of population substructure will also be largely unaffected. However, analyses that are dependent on locus heterozygosity, which can be used for studying population bottlenecks, or those that study selection using extended haplotype homozygosity may be significantly affected by breed of origin of the SNPs. 2010 CSIRO.
Rainfall variability is a challenge to sustainable and pro. table cattle production in northern Australia. Strategies recommended to manage for rainfall variability, like light or variable stocking, are not widely adopted. This is due partly to the perception that sustainability and profitability are incompatible. A large, long-term grazing trial was initiated in 1997 in north Queensland, Australia, to test the effect of different grazing strategies on cattle production. These strategies are: (i) constant light stocking (LSR) at long-term carrying capacity (LTCC); (ii) constant heavy stocking (HSR) at twice LTCC; (iii) rotational wet-season spelling (R/Spell) at 1.5 LTCC; (iv) variable stocking (VAR), with stocking rates adjusted in May based on available pasture; and (v) a Southern Oscillation Index (SOI) variable strategy, with stocking rates adjusted in November, based on available pasture and SOI seasonal forecasts. Animal performance varied markedly over the 10 years for which data is presented, due to pronounced differences in rainfall and pasture availability. Nonetheless, lighter stocking at or about LTCC consistently gave the best individual liveweight gain (LWG), condition score and skeletal growth; mean LWG per annum was thus highest in the LSR (113 kg), intermediate in the R/Spell (104 kg) and lowest in the HSR(86 kg). MeanLWGwas 106 kg in the VAR and 103 kg in the SOI but, in all years, the relative performance of these strategies was dependent upon the stocking rate applied. After 2 years on the trial, steers from lightly stocked strategies were 60-100 kg heavier and received appreciable carcass price premiums at the meatworks compared to those under heavy stocking. In contrast, LWG per unit area was greatest at stocking rates of about twice LTCC; mean LWG/ha was thus greatest in the HSR (21 kg/ha), but this strategy required drought feeding in four of the 10 years and was unsustainable. Although LWG/ha was lower in the LSR (mean 14 kg/ha), or in strategies that reduced stocking rates in dry years like the VAR(mean 18 kg/ha) and SOI (mean 17 kg/ha), these strategies did not require drought feeding and appeared sustainable. The R/Spell strategy (mean 16 kg/ha) was compromised by an ill-timed fire, but also performed satisfactorily. The present results provide important evidence challenging the assumption that sustainable management in a variable environment is unprofitable. Further research is required to fully quantify the long-term effects of these strategies on land condition and profitability and to extrapolate the results to breeder performance at the property level.
Nutrition is a mature science with well established principles for energy, protein and mineral metabolism based on known metabolic pathways. The quantitative requirements are summarised within various international feeding standards and models. However, when these are applied to specific circumstances, especially in northern Australia, the response of the animal to nutrient supply does not always agree with that predicted from the feeding standards or the error of prediction is not sufficiently accurate for practical use. There is a need for the continual testing of these relationships within production systems. Molecular methods have the potential to discover new metabolic relationships within tissues and characterise the microbial ecology and its relationship to rumen function. Suitable problem models based on growth, meat quality, reproduction, milk and fibre production, and environmental consequences need to be identified. We suggest that production systems designed to meet market weight for age specifications, growth paths and compensatory growth, skeletal growth, parasites, fatty acid isomers, adaptation to low crude protein diets, rumen microbial ecology, epigenetics, remote data acquisition and animal management, greenhouse gas emission, and C balance of various production systems are important problem models, the research of which will benefit the future of the livestock industries in Australia.
This paper describes the performance of a prototype telemetric intraruminal bolus that measures and records pH continuously, can be delivered orally to the reticulum via bolling gun, has no external attachments and allows unrestricted activity of the animal. When interrogated by wireless the bolus transmits the recorded data to an operator standing beside the animal with a handheld receiving station. Boluses were placed in fistulated animals to enable direct comparison with samples obtained directly from the rumen and measured with a laboratory instrument. Overall, the mean (±s.d.) pH recorded on the manually collected samples (pH 6.64 ± 0.67) was generally less than that of the continuously measured telemetric system (pH 7.03 ± 0.54) with a correlation of r = 0.93 (P < 0.01). Data are presented to show typical diurnal and grain-enforced changes in pH recorded in a rumen over a 70-day period. The development of the Well Cow pH bolus device potentially enables researchers, dairy farmers and feedlot managers to monitor rumen function of any ruminant over prolonged periods without the need for invasive sampling. Enemark et al. (2003) considered that a 14–21-day observational period is required to properly monitor for conditions such as subacute ruminal acidosis. Whilst significant correlation (P < 0.01; r = 0.982) existed between the two readings for the first 40 days of continuous recording, the Well Cow pH bolus reading started to deviate significantly from the directly measured value thereafter. Regardless, a continuously measuring functional life of up to 40 days indicates that the current prototype has the capacity to accurately detect subacute ruminal acidosis.
With the increased incidence of parasite resistance to chemical anthelmintics worldwide novel approaches to manage parasite infection, such as medicinal plants and their extracts, are being investigated by the scientific community. The current study tested the effect of three rates of garlic (0.9, 1.8 and 3.6%) in a pelleted ration on Haemonchus contortus in sheep. Thirty-nine Merino wether lambs aged 6 months were divided into five treatment groups, including three garlic dose rates and two control groups that received no garlic. All animals were infected with 4000 L3 H. contortus larvae 3 weeks after allocation to treatments. A positive control group was drenched with abamectin 28 days after infection. The synthetic drench was effective in controlling the parasites, but there was no reduction in either worm egg counts (WEC) or total worm count due to the garlic. The 3.6% garlic treatment had significantly lower (P <0.05) liveweight, feed intake, body condition score and feed conversion ratio than any of the other treatment groups, suggesting that this level of garlic had a low level of anti-nutritional properties. There was an interaction between faecal WEC and voluntary feed intake overtime, with the animals with higher voluntary feed intake having lower WEC over time.
The present study set out to test the hypothesis through field and simulation studies that the incorporation of short-term summer legumes, particularly annual legume lablab (Lablab purpureus cv. Highworth), in a fallow-wheat cropping system will improve the overall economic and environmental benefits in south-west Queensland. Replicated, large plot experiments were established at five commercial properties by using their machineries, and two smaller plot experiments were established at two intensively researched sites (Roma and St George). A detailed study on various other biennial and perennial summer forage legumes in rotation with wheat and influenced by phosphorus (P) supply (10 and 40 kg P/ha) was also carried out at the two research sites. The other legumes were lucerne (Medicago sativa), butterfly pea (Clitoria ternatea) and burgundy bean (Macroptilium bracteatum). After legumes, spring wheat (Triticum aestivum) was sown into the legume stubble. The annual lablab produced the highest forage yield, whereas germination, establishment and production of other biennial and perennial legumes were poor, particularly in the red soil at St George. At the commercial sites, only lablab-wheat rotations were experimented, with an increased supply of P in subsurface soil (20 kg P/ha). The lablab grown at the commercial sites yielded between 3 and 6 t/ha forage yield over 2-3 month periods, whereas the following wheat crop with no applied fertiliser yielded between 0.5 to 2.5 t/ha. The wheat following lablab yielded 30% less, on average, than the wheat in a fallow plot, and the profitability of wheat following lablab was slightly higher than that of the wheat following fallow because of greater costs associated with fallow management. The profitability of the lablab-wheat phase was determined after accounting for the input costs and additional costs associated with the management of fallow and in-crop herbicide applications for a fallow-wheat system. The economic and environmental benefits of forage lablab and wheat cropping were also assessed through simulations over a long-term climatic pattern by using economic (PreCAPS) and biophysical (Agricultural Production Systems Simulation, APSIM) decision support models. Analysis of the long-term rainfall pattern (70% in summer and 30% in winter) and simulation studies indicated that ~50% time a wheat crop would not be planted or would fail to produce a profitable crop (grain yield less than 1 t/ha) because of less and unreliable rainfall in winter. Whereas forage lablab in summer would produce a profitable crop, with a forage yield of more than 3 t/ha, ~90% times. Only 14 wheat crops (of 26 growing seasons, i.e. 54%) were profitable, compared with 22 forage lablab (of 25 seasons, i.e. 90%). An opportunistic double-cropping of lablab in summer and wheat in winter is also viable and profitable in 50% of the years. Simulation studies also indicated that an opportunistic lablab-wheat cropping can reduce the potential runoff+drainage by more than 40% in the Roma region, leading to improved economic and environmental benefits.
An experiment using herds of similar to 20 cows (farmlets) assessed the effects of high stocking rates on production and profitability of feeding systems based on dryland and irrigated perennial ryegrass-based pastures in a Mediterranean environment in South Australia over 4 years. A target level of milk production of 7000 L/cow.year was set, based on predicted intakes of 2.7 t DM/cow.year as concentrates, pasture intakes from 1.5 to 2.7 t/cow.year and purchased fodder. In years 1 and 2, up to 1.5 t DM/cow.year of purchased fodder was used and in years 3 and 4 the amounts were increased if necessary to enable levels of milk production per cow to be maintained at target levels. Cows in dryland farmlets calved in March to May inclusive and were stocked at 2.5, 2.9, 3.3, 3.6 and 4.1 cows/ha, while those in irrigated farmlets calved in August to October inclusive and were stocked at 4.1, 5.2, 6.3 and 7.4 cows/ha. In the first 2 years, when inputs of purchased fodder were limited, milk production per cow was reduced with higher stocking rates (P < 0.01), but in years 3 and 4 there were no differences. Mean production was 7149 kg/cow.year in years 1 and 2, and 8162 kg/cow.year in years 3 and 4. Production per hectare was very closely related to stocking rate in all years ( P < 0.01), increasing from 18 to 34 t milk/ha.year for dryland farmlets ( 1300 to 2200 kg milk solids/ha) and from 30 to 60 t milk/ha.year for irrigated farmlets ( 2200 to 4100 kg milk solids/ha). Almost all of these increases were attributed to the increases in grain and purchased fodder inputs associated with the increases in stocking rate. Net pasture accumulation rates and pasture harvest were generally not altered with stocking rate, though as stocking rate increased there was a change to more of the pasture being grazed and less conserved in both dryland and irrigated farmlets. Total pasture harvest averaged similar to 8 and 14 t DM/ha.year for dryland and irrigated pastures, respectively. An exception was at the highest stocking rate under irrigation, where pugging during winter was associated with a 14% reduction in annual pasture growth. There were several indications that these high stocking rates may not be sustainable without substantial changes in management practice. There were large and positive nutrient balances and associated increases in soil mineral content (P < 0.01), especially for phosphorus and nitrate nitrogen, with both stocking rate and succeeding years. Levels under irrigation were considerably higher ( up to 90 and 240 mg/kg of soil for nitrate nitrogen and phosphorus, respectively) than under dryland pastures ( 60 and 140 mg/kg, respectively). Soil organic carbon levels did not change with stocking rate, indicating a high level of utilisation of forage grown. Weed ingress was also high (to 22% DM) in all treatments and especially in heavily stocked irrigated pastures during winter. It was concluded the higher stocking rates used exceeded those that are feasible for Mediterranean pastures in this environment and upper levels of stocking are suggested to be 2.5 cows/ha for dryland pastures and 5.2 cows/ha for irrigated pastures. To sustain these suggested stocking rates will require further development of management practices to avoid large increases in soil minerals and weed invasion of pastures.
Leucaena leucocephala subsp. glabrata (leucaena)-grass pastures are productive, perennial and long-lived (40 years). However, little is known about changes in the productivity of these pastures as they age even though they are grazed intensively and are rarely fertilised. A postal survey of beef cattle producers in Queensland who grow leucaena pastures was conducted. The questionnaire gathered information regarding: property location; extent and age of leucaena pastures; soil type; leucaena and grass establishment methodology; grazing and fertiliser management; and grazier perceptions of changes over time in leucaena productivity, grass growth and ground cover, prevalence of undesirable grasses and weeds, and livestock productivity. Graziers were asked to report on both young (10 years old) and aging (10 years old) pastures under their management. Eighty-eight graziers responded describing 124 leucaena paddocks covering 11750 ha. The survey results described the typical physical and management characteristics of leucaena pastures in Queensland. Graziers reported a decline in leucaena productivity in 58% of aging pastures, and declines in grass growth (32%) and livestock productivity (42%) associated with declining leucaena growth. Leucaena decline was greater in soil types of marginal initial fertility, particularly brigalow clay, soft wood scrub, downs and duplex soils. Maintenance fertiliser was not applied to most (98%) leucaena pastures surveyed despite significant amounts of nutrient removal, particularly phosphorus and sulphur, occurring over prolonged periods of moderate to high grazing pressure. It is predicted that large areas of leucaena pasture will continue to suffer soil nutrient depletion under current management practices. Research is needed to develop ameliorative actions to reinvigorate pasture productivity. 2010 CSIRO.
The present study was conducted to test the effects of l-arginine supplementation of wheat-based diets on the pregnancy outcome of gilts. Pregnant gilts (Yorkshire × Landrace, n ≤ 113) were assigned randomly into two groups representing dietary supplementation with 0.1% l-arginine as l-arginine-HCl or 0.17% l-alanine (isonitrogenous control) between Days 30 and 110 of pregnancy. Blood samples were obtained from the ear vein on Days 30, 70 and 90 of pregnancy. Compared with the control, arginine supplementation increased the total number of piglets born by 1.10 per litter and the number of live-born piglets by 1.10 per litter (P < 0.05). Plasma concentration of spermine was higher in gilts fed arginine diets than in those fed control diets at Day 90 of pregnancy (P < 0.05). Dietary arginine supplementation increased plasma concentration of IGF-I of gilts at Day 90 of pregnancy (P < 0.01) and plasma concentrations of arginine, proline and ornithine at Days 70 and 90 of pregnancy (P < 0.05). These results indicated that low-level supplementation (0.1%) of l-arginine-HCl of wheat-based diets beneficially enhances the reproductive performance of gilts and is feasible for use in commercial production.
Context Few studies have been conducted with the Brazilian Embrapa 051 hens to improve the feed conversion rate and control skeletal health in this breed. Aims To determine how different feeding volumes affect the laying rate and bone quality of the Embrapa 051 (E051) strain in comparison with Lohmann Brown (LB). Methods In total, 600 E051 and 200 LB hens were subjected to the following treatments: (1) control (LB fed 100% of their dietary requirements), (2) E051 fed 93% of the control diet, (3) E051 fed 100% of the control diet, and (4) E051 fed 107% of the control diet. Key results Throughout the 37–72 weeks of age, LB hens presented a higher egg production rate than E051 hens (P < 0.05). The bodyweight and egg production rate were lower in E051 when hens received 93% of the E051 control diet. The E051 hens achieved higher values for tibia weight and length and Seedor index than did LB hens (P < 0.05). At Week 40, the E051 hens fed 93% of the control diet presented a greater tibia weight (12.6 vs 11.5 g), length (124.5 vs 118.9 mm) and strength (21.9 vs 15.5 kgf), Seedor index (101.7 vs 96.13), and ash (33.0 vs 29.6%), calcium (11.1 vs 9.8%) and phosphorus (4.9 vs 4.5%) concentrations than did LB hens. However, at 73 weeks of age, the only differences observed in favour of E051 hens fed 93% of the control diet were for tibia weight, tibia length and tibia strength in comparison with LB hens (P < 0.05). Conclusions LB hens showed a higher performance, but lower bone quality than did E051 hens. E051 receiving 7% less feed showed a reduced laying rate but, in contrast, better bone quality. This study showed that the best feeding strategy for Embrapa 051 hens was to use the same feeding volume as recommended for Lohmann Brown hens. Implications Despite E051 hens showing a lower laying rate than that of LB hens, especially when receiving a restricted amount of feed, E051 is an accessible alternative breed with excellent bone quality for free-range systems in Brazil.
Context Vitamin D supplementation plays a key role because its actions positively affect the animal’s overall health for optimal performance. Aims To assess partial cholecalciferol replacement with 1,25-dihydroxycholecalciferol glycoside for piglets on nutrient digestibility and daily balance of calcium and phosphorus, growth performance and blood metabolites. Methods To test digestibility, a total of 36 whole male piglets (18.79 ± 3.37 kg BW) were assigned in a randomised complete block design, with four treatments: (1) D3 (100% of the vitamin D supplemented with 1969 IU of cholecalciferol), (2) no supplemental sources of vitamin D (control), (3) D3 (50% of requirement + 0.375 μg of 1,25(OH)2D3 glycoside) or (4) 100% supplemented with 0.750 μg of 1,25(OH)2D3 glycoside. Nine replicates were performed, with one animal per experimental unit. For growth performance (Experiment II), a total of 128 whole male piglets (6.82 ± 0.38 kg BW) were distributed in a randomised complete block design, with four treatments: (1) 100% D3 (2707 IU in the pre-starter phase I, 2405 IU in the pre-starter phase II and 1969 IU in the starter phase), (2) 50% D3 + 0.25 μg of 1,25(OH)2D3 glycoside, (3) 25% D3 + 0.375 μg of 1,25(OH)2D3 glycoside or (4) 100% supplemented with 0.50 μg of 1,25(OH)2D3 glycoside. Eight replicates were conducted, with and four animals per experimental unit. Key results The apparent digestibility of nutrients and mineral balance were not influenced (P > 0.1). The results of Experiment II indicate effects (P < 0.1) of vitamin D supplementation on the growth performance evaluated during the nursery phase. Plasma calcium concentrations in the pre-starter II phase showed (P < 0.1) the highest concentration in the 50/50 treatment. Alkaline phosphatase showed (P < 0.001) a difference between treatments in the starter phase, with treatment 25/75 promoting the lowest plasma value. Conclusions Cholecalciferol or 1,25-dihydroxycholecalciferol glycoside resulted in similar digestibility and balance of calcium and phosphorus, even though the combination increased plasma calcium and alkaline phosphatase concentration in piglets. In addition, the partial replacement reduced the voluntary feed intake of piglets during nursery phase. Implications This investigation provided new information on partial cholecalciferol replacement with 1,25-dihydroxycholecalciferol glycoside in piglet starter as an alternative in post-weaning nutrition.
Angiopoietin-like protein 3 (Angptl3) may promote adipose formation. The present study investigated the beneficial effect of 1,3,5,8-tetrahydroxyxanthone (Xan), a naturally occurring polyphenol agent, on carcass characteristics and meat quality in pigs and the mechanisms involved. Forty-eight Duroc x Landrace x Yorkshire pigs (65.3 +/- 7.8 kg) were randomly divided into four groups: control group, untreated high lipid diet (HLD) group and two groups of HLD with Xan (1 or 3%). Forty-two days later, Xan (1 or 3%) treatment significantly increased percentage lean, loin eye area, colour, expression and activity of adipose tissue lipoprotein lipase activity and decreased percentage fat, backfat thickness, total cholesterol concentration, triglyceride concentration, and Angptl3 mRNA expression. The present results suggest that the beneficial effect of Xan on carcass characteristics and meat quality may be related to decreased expression of Angptl3 in pig.
Continuous postharvest treatment of cut rose flowers (Rosa hybrida L. cv. Diana) with maleic acid hydrazide (1.2-dihydro-3,6-pyridazinedione, MH) at 560.5 8-hydroxyquinoline sulfate (HQS) at 388.4 HQS, MH + HQS or sucrose + HQS treatments. The longevity of flowers in MH + sucrose in combination with HQS was extended for 18 days after vase treatments, whereas the longevity of cut flowers was only 4, 6 and 8 days for HQS, MH + HQS and sucrose + HQS, respectively. Cut roses treated with MH + sucrose + HQS in vase solution exhibited greater water uptake and less water loss than those in HQS. The concentrations of various sugars in petals were highest in the sucrose + HQS treatment, and MH + sucrose + HQS > MH + HQS > HQS. Ethylene production was significantly lower in sucrose + HQS or MH + sucrose + HQS treatments in comparison to MH + HQS, or HQS.
An experiment was conducted to define the lysine requirement of neonatal pigs fed a liquid diet up to 5.5 kg bodyweight (BW). Neonatal pigs, 1-2 days old, with an initial bodyweight of 1.63 +/- 0.04 kg, were randomly allotted to 10 isocaloric diets varying in lysine concentration from 0.76 to 1.62 g lysine/MJ gross energy (GE). Diets were formulated using whey protein concentrate and casein as protein sources and contained similar balance of indispensable amino acids. On day 1 of the experiment, pigs were fed 350 g liquid diet/kg metabolic bodyweight (BW0.75) according to the average BW of all pigs. On day 2, feeding rate was increased to 400 g/kg BW0.75. Increments were 100 g/kg BW0.75 per day for the subsequent 3 days until pigs reached 700 g/kg BW0.75 on day 5. Thereafter, feed was offered to pigs at a common feeding level of 700 g/kg BW0.75 each day until they reached 5.5 kg BW. Feed intake and BW were measured daily. Concentration of fat in the carcass decreased (P < 0.05) and the ratio of crude protein (CP) to fat in the carcass increased (P < 0.05) linearly as lysine inclusion increased. Both average daily gain and CP accretion increased (quadratic, P < 0.05), whereas fat accretion decreased (quadratic, P < 0.05) as lysine inclusion increased. Using the maximum point of the quadratic function, the estimated dietary lysine required for maximal growth (271 g/day) and CP accretion (45.2 g/day) was 1.41 and 1.32 g lysine/MJ GE, respectively. The dietary lysine required, estimating the requirement at the lower limit of the 95% confidence interval for CP accretion of 42.9 g/day, was 1.12 g lysine/MJ GE. Gross efficiency of CP deposition (CP deposition/CP intake) achieved a maximum of 0.85 at 1.01 g lysine/MJ GE.
A cortisol metabolite, 11-ketoetiocholanolone (11-k), is widely used in monitoring stress in several vertebrates, and can be detected by immunoassay. However, these assays have certain limitations with respect to specificity. Also, differences in the excretion of faecal glucocorticoid metabolites (FGM) among species and even between sexes make validation necessary in each case. Therefore, our aims were, first, to develop and validate a high-pressure liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) methodology for monitoring 11-k in faeces of Iberian red deer (Cervus elaphus hispanicus), and second, to investigate the capability of our method to determine variations of this FGM in a longitudinal study. Third, and finally, we assessed the correspondence between faecal 11-k concentrations and plasma cortisol. An adrenocorticotropic hormone (ACTH) test was performed on six red deer stags translocated and kept in captivity for a week and faecal samples were collected twice a day. One single blood and faecal sample from another seven stags was also collected after 2 weeks in captivity. The results of the longitudinal study showed a first peak in 11-k 36 h after the ACTH test and handling, and a second peak at 120 h of being kept indoors. Maximum concentrations of 11-k ranged from 22.71 to 375.68 ng/g. In the second stag group, 11-k concentrations of 25.09 +/- 20.53 ng/g had a correlation of r(2) = 0.88 with the concentration of plasma cortisol, which was 54.6 +/- 55.1 ng/mL. This technique is capable of detecting changes in the concentrations of faecal 11-k. The values determined have a good correlation with the cortisol concentration in blood, and we also detected differences in different individuals' responses to the same stressors.
Growth data and feed intakes were recorded from 333 male, Friesian calves from birth to 11 weeks of age. The calves came from seven experiments. All calves were weaned from milk replacer at five weeks and fed a starter from two to eleven weeks of age. The average birth weight of the calves was 42.6 kg, they gained 13.6 kg to weaning at five weeks and 32.2 kg from weaning to 11 weeks of age. There was a significant positive correlation between birth weight and weight at weaning and 11 weeks, but the correlation between birth weight and weight gain to 11 weeks was not significant. The correlation coefficient for the weight gain pre-and post-weaning was 0.20 over all calves. There was a significant negative (r = -0.26) correlation between the weight gain post-weaning and the feed conversion ratio. Hence, it is concluded that birth weight is a poor indicator of subsequent weight gains.
One hundred and sixty female Large White × Landrace pigs were obtained at 3 weeks of age, average liveweight (LW) 5.5 ± 0.08 kg, stratified on LW and allocated to four treatments in a factorial design that consisted of two housing treatments, conventional (C) or deep-litter (D), across two growth periods: early (3–13 weeks of age) and late (13–24 weeks of age). At 13 weeks of age eight pigs per treatment (n = 32) were slaughtered, and the remaining pigs (n = 128) moved to new pens where they remained until slaughter at 24 weeks of age. Moving pigs into a new housing system caused a growth reduction, as indicated by significantly lower LW (P = 0.003), compared with pigs that remained within the same housing system, regardless of whether the new system was C or D. Carcass composition results indicated that pigs finished in the D system (24 weeks of age) were not fatter than pigs raised in C housing, with pigs raised entirely in C housing tending to be the fattest (P = 0.090). There was an effect of housing on fat distribution within the carcass where pigs finished in D housing had significantly less fat in the belly primal compared with pigs finished in the C facilities (35.3 versus 31.2%, P = 0.030). These findings suggest that the strategy of moving pigs from D housing to C housing for finishing, to reduce carcass fatness and improve pig growth performance, was not successful as pigs were fatter, lighter and less efficient than pigs of the same age housed in D from wean to finish.
The objective of this trial was to study the impact of slaughter weight (SW) class: heavy (≥120 kg) or light (<120 kg) on carcass fatness, development of main lean cuts and fat composition in barrows and gilts intended for dry-cured ham and shoulder elaboration. A total of 181 Duroc × (Landrace × Large White) pigs was used, being 94 barrows and 87 gilts. Carcasses from barrows had lower ham compactness but higher shoulder:ham weight ratio than those from gilts. The allometric growth coefficient of ham was higher in gilts whereas those for shoulder, loin and shoulder/ham were higher in barrows. An interaction sex × SW class was found for carcass fatness; the increase of fat thickness was higher in barrows than in gilts in light SW class but higher in gilts than in barrows in heavy SW class. In addition, the allometric growth coefficients for ham, loin and shoulder:ham ratio were higher in light than in heavy pigs. Percentage of rejected carcasses at slaughterhouse, due to lack of fat thickness, was higher for females than for barrows and for light than for heavy pigs. Sex and SW class had no effect on intramuscular fat content. However, more saturation was found in fat (intramuscular) from barrows and in that (subcutaneous) from light pigs. It can be concluded that carcasses from barrows are commercially more suitable than those from gilts and heavy SW might be more interesting when animals are intended for Teruel dry-cured ham and shoulder production.
Physical performance data from 13 dairy farms in Western Australia, six feeding all concentrate in the milking parlour and seven feeding a portion of concentrate in a partial mixed ration (PMR) with forage, were collected between March 2012 and June 2013. Each farm was visited 13 times at intervals of 4-6 weeks, and feed intake and milk production was recorded on each visit. Four farms had access to fresh pasture all year round via irrigation. Milk yield (MY) and composition data was calculated daily from milk processor records. Pasture dry matter intake (DMI) was estimated based on metabolisable energy supply and requirements according to published feeding standards. All milk and feed-related measures were significantly affected by visit date (P < 0.01). Mean annual concentrate intake and MY was 2082 ± 344 kg/cow and 7679 ± 684 kg/cow, respectively. Daily concentrate DMI was greatest in May 2012 (8.9 ± 2.2 kg/cow), near the end of the non-grazing season, and lowest in August 2012 (5.1 ± 1.5 kg/cow). On an average annual basis, PMR farms provided 22 ± 15% of total concentrate fed as part of a PMR, and 28 ± 11% of total concentrates and by-products fed as part of a PMR. Daily grazed pasture DMI was highest on all farms in September 2012 (12.9 ± 2.4 kg/cow), and averaged 6.6 kg/cow on the four irrigated farms between January and May. Daily yield of energy-corrected milk was highest in September 2012 (26.9 kg/cow) and lowest in January 2013 (21.9 kg/cow). Milk fat content was highest in summer and lowest in winter; the reverse was true of milk protein. Feed conversion efficiency was significantly affected by visit date, but mean feed conversion efficiency was the same (1.37) for in-parlour and PMR farms. Overall there was some evidence that PMR feeding systems on Western Australian dairy farms are not optimised to their full potential, but a high degree of variability in performance between all farms was also apparent.
The aims of the present study were to describe intermuscular differences in meat-quality traits in 15 young-sheep muscles, and to study the associations between meat quality and fibre typing across all (pooled) muscles as well as in previously selected homogeneous contractile–metabolic groups of muscles (slow-oxidative, intermediate and fast-glycolytic muscles). Meat-quality traits (pH, colour, expressed juice, cooking losses, tenderness and sarcomere length) and fibre typing were evaluated after 24 h of slaughter in 15 muscles from five cross-bred young sheep. Across all the studied muscles, intermuscular differences in some meat-quality traits (pH24, a* and expressed juice) seemed to be mainly explained by muscle oxidative activity, while intermuscular variation in other meat-quality traits (L*, b* and Warner–Bratzler shear force) were mainly explained by differences in fibre sizes. Within fast-glycolytic muscles, larger fast-glycolytic fibres and reduced oxidative activity were generally associated with lower ultimate pH, higher L* values, lower a* values and longer sarcomeres. Within intermediate muscles, larger fast-glycolytic fibres and reduced oxidative activity were generally associated with lower ultimate pH, higher L* values, shorter sarcomeres and reduced meat tenderness. Within slow-oxidative muscles, larger fast-glycolytic fibres and reduced oxidative activity were generally associated with lower amounts of expressed juice, lower a* values and reduced meat tenderness. The present study has contributed to a better understanding of the influence of muscle fibre types on intermuscular meat-quality variation, suggesting that although muscle fibre diversity may explain, at least in part, intermuscular differences in meat quality, these associations can also slightly vary among muscle contractile–metabolic groups.
In the present study, the effects of restricted intake of the final finishing diet as a means of dietary adaptation compared with diets increasing in concentrate content (step-up) over periods of 14 and 21 days on growth performance, carcass characteristics, feeding behaviour and rumen morphometrics of Nellore cattle were evaluated. One hundred and twenty 20 months old Nellore bulls (initial BW = 372.2 kg, s.d. = 21.5 kg) were randomly allocated in 24 pens (n = 5 per pen) and fed for 84 days. The study had a completely randomised design with a 2 × 2 factorial arrangement: adaptation using both 14-day and 21-day step-up and restriction protocols. Each treatment was replicated 6 times. One bull per pen was slaughtered (n = 24) at the end of adaptation period to evaluate rumen morphometrics. The remaining bulls (n = 96) were slaughtered at the end of experimental period. Interactions were observed (P < 0.05) for growth performance, feeding behaviour and rumen morphometrics variables. Overall, no protocol or adaptation length main effect (P > 0.05) was observed for any of the growth rate and carcass traits evaluated, except for hot carcass weight (P = 0.03) and dressing percentage (P = 0.04), where bulls adapted for 14 days had heavier carcasses and increased dressing percentage when compared with cattle adapted for 21 days. Cattle adapted for 21 days had a larger (P = 0.005) rumen wall absorptive surface area at the end of adaptation period than those adapted for 14 days; however, no differences were detected at the end of finishing period. Thus, Nellore yearling bulls could be adapted for 14 days regardless of the protocol.
Context The regulation of milk lipids is important for the evaluation of dairy cows’ performance. Lipids are produced and secreted by mammary gland under the regulation of steroid hormones, growth factors and microRNAs (miRNAs). MicroRNAs have been verified to be involved in numerous biological processes. Previous studies have shown that miR-141 is expressed at higher levels in dairy cows at peak lactation than in those at early lactation. However, the roles of miR-141 in bovine mammary epithelial cells (BMECs) and the mechanisms how it affects lipid metabolism are as yet unknown. Aims The aims of this study were to clarify (i) the molecular mechanisms of miR-141 in milk lipid metabolism, and (ii) how miR-141 affects milk lipid metabolism in BMECs. Methods Triglycerides were observed in BMECs using triglyceride analysis after overexpression or inhibition of miR-141; selected potential candidate genes that are targeted by miR-141 using TargetScan. The regulatory relationship among miR-141, SIRT1 gene and lipid metabolism-related genes (SREBF1, FASN and PPARγ) by using the dual luciferase assay, quantitative real-time PCR and western blotting. Key results Through overexpression or inhibition of miR-141 expression, we found that miR-141 promoted lipid metabolism in BMECs and an increase in triglycerides was observed in these cells. Further, miR-141 targets the 3′UTR of SIRT1 mRNA, and negative regulates the expression of SIRT1 gene in BMECs. Also, the expression levels of SREBF1, FASN and PPARγ, which are related to milk lipid metabolism, were also altered after overexpression miR-141. Conclusions Our results have revealed that miR-141 could promote milk lipid metabolism in BMECs by means of negative regulates SIRT1 gene and positive effects lipid metabolism-related genes (SREBF1, FASN and PPARγ) in BMECs. Implications Our research indicates that miR-141 could be considered a marker in cattle breeding to obtain high quality dairy products. It would be useful to study the function of miRNAs in milk lipid metabolism and synthesis. In the long term these findings might be helpful in developing practical means to improve the quality of ruminant milk.
Context Gastrointestinal microorganisms play an important role in ruminant digestion and metabolism, immune regulation and disease prevention and control. Different parts of the digestive tract have different functions and microbial community structures. Aims This study aims to explore the microbial diversity in the rumen and the small intestine of Xinong Saanen dairy goats. Methods Rumen fluid and jejunum fluid from three Xinong Saanen dairy bucks with the average slaughter weight of 33.93 ± 0.68 kg were collected and analysed for microbial diversity, by using 16S rRNA gene high-throughput sequencing. Key results In total, 1118 operational taxonomic units (OTUs) were identified, with 1020 OTUs and 649 OTUs being clustered to rumen and jejunum samples respectively. Alpha-diversity indices were significantly (P < 0.05) different between rumen and jejunum, as indicated by the fact that the rumen microbial community diversity, richness and uniformity/evenness were higher than those of jejunum. At the phylum level, the dominant phyla in the rumen were Bacteroidetes (66.7%) and Firmicutes (25.1%), accounting for 91.8% of the rumen microorganisms. The dominant phylum in the jejunum was Firmicutes, accounting for 73.0% of the jejunum microorganisms. At the genus level, the dominant bacteria in the rumen were Prevotella_1, norank_f_Bacteroidales_BS11_gut_group, Rikenellaceae_RC9_gut_group, Christensenellaceae_R-7_group and Family_XIII_AD3011_group, whereas the dominant bacteria in the jejunum were Omboutsia, Aeriscardovia, Intestinibacter, unclassified_f_Peptostreptococcaceae and unclassified_f_Bifidobacteriaceae. Clusters of Orthologous Groups (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) results showed that the major functions of microorganisms in the rumen and jejunum were carbohydrate metabolism, amino acid metabolism, nucleotide metabolism, membrane transport and translation. Interestingly, fructose and mannose metabolism and peptidoglycan biosynthesis were abundant in the rumen, while homologous recombination and nucleotide excision repair were abundant in the jejunum. Conclusions Our study clarified the differences in microbial diversity and community structure between the rumen and the jejunum in Xinong Saanen dairy goats. Prevotella was the most predominant genus in the rumen, compared with Romboutsia, Bifidobacterium as well as Peptostreptococcaceae genera, which were the predominant genera in the jejunum. Implications In combination with the functional prediction of microorganisms and the metabolic characteristics of different parts of the digestive tract in ruminants, our findings provided information for further exploring the relationship among genes, species and functions of microorganisms and their hosts’ nutritional and physiological functions.
The pampas deer (Ozotoceros bezoarticus) is one of the most endangered neotropical mammals in Uruguay. Although it has a wide geographic distribution in south-eastern South America (from 5S to 41S), the habitat required by this species has been greatly reduced by agriculture and urbanisation. The species decline was due to human activities, and currently two isolated populations survive. The parasitological load is a good indicator of the health of the species and the ecosystem. The objective of the present study was to survey and determine the parasitological composition of the two Uruguayan pampas deer populations. We quantified the coproparasite load, by analysing the effect of seasonality through the year, the micro-ecosystem environment, the topography and also the livestock of the paddock. The taxonomic assessment was based on adult individuals obtained from the post mortem necropsy examination in individuals found dead in the field. The genera of the endoparasites recorded through the morphological eggs, larvae and/or adults were Trichuris, Capillaria, Strongyloides, Fasciola, Paramphistomum, Moniezia, Haemonchus, Ostertagia, Trichostrongylus, Oesophagostomum and Coccidias ooquiste. Our results showed that the parasitological community in the pampas deer is strongly correlated with the environmental conditions, topology, micro-ecosystem and the land use, as well as the effect of the livestock load. Moreover, because we have diagnosed the same genera of helminths in domestic ruminants, we recommend balancing the carrying capacities of the field paddocks, and performing periodical surveys of the livestock parasite load that will be helpful in maintaining control at lower values.
Twin- and triplet-born lambs are smaller and lighter at birth than singletons and remain so until at least 1 year of age. However, there is little evidence in the literature to demonstrate if these smaller/lighter twin- and triplet-born lambs are metabolically different to singletons later in life. Additionally, many studies have demonstrated that dam nutrition during the periconceptual period can program the fetus in utero, influencing development, growth and performance later in life. However, little is known regarding the impact of differing levels of maternal nutrition before the periconceptual period, during the period of preantral follicle development. This study aimed to determine if dam pre-breeding nutrition (High versus Maintenance, 113-71 days pre-breeding) and birth rank (single versus twin versus triplet) affected the metabolic responses of ewes at 18 months of age, to an intravenous glucose (0.17 g/kg liveweight) (GTT) and insulin (0.15 IU/kg liveweight) (ITT) tolerance test. Dam pre-breeding nutrition had no effect (P > 0.05) on glucose and insulin responses to GTT, or glucose and cortisol responses to ITT. However, before both GTT and ITT, ewes born to High-fed dams had greater (P < 0.05) beta-hydroxybutyrate (beta-HBA) baselines than those born to Maintenance-fed dams, and also had greater (P < 0.05) maximum beta-HBA change in response to both GTT and ITT. Birth rank tended (P = 0.06) to affect maximum glucose concentration change in response to glucose administration, with twin- born ewes having a greater increase in glucose compared with both singletons (P = 0.06) and triplet-born (P < 0.05) ewes in response to a glucose challenge. Insulin area under the curve 0-120 min after glucose administration of twin- born ewes was lower (P = 0.05) than both single- and triplet-born ewes. Prior to ITT, baseline beta-HBA concentrations of single- born ewes were lower (P < 0.05) than triplet-born ewes. Single-born ewes had a reduced (P < 0.05) decrease in beta-HBA change compared with twin- and triplet-born ewes in response to ITT. In summary, this study showed little difference in glucose and insulin metabolism of single-, twin- and triplet-born lambs at 18 months of age. However, the level of dam nutrition 113-71 days pre-breeding appears to have lasting effects on beta-HBA metabolism in ewe progeny. The next step is to determine if these metabolic differences result in any measurable animal performance differences, as this would have implications for feeding regimes of ewes before mating and selection of appropriate ewe progeny for use as replacement animals.