Animal Production Science最新文献

Estimates of enteric methane emissions for agricultural emissions trading schemes or national inventories can be a simple single emission factor, but the accuracy of the predictions may be affected by other diet- and animal-related parameters.

Determine the animal and dietary factors that affect methane yield (methane per unit of dry-matter intake) in pasture-fed cattle.

Methane emissions and dry-matter intake (DMI) of cattle of various ages and in different physiological stages that were fed different-quality fresh-cut pastures were quantified in respiration chambers. The animals used in the various trials were post-weaned calves, heifers and steers of various ages and some older lactating dairy cows. Diet quality of the pastures offered was determined using near-infrared spectroscopy. Mixed linear modelling was used to assess the impacts of animal and diet parameters on methane emissions.

Our results indicated that diet quality does not have a major effect on methane production. For individual composition parameters, the correlation (Pearson’s r) with methane production was less than 0.25. Only estimates of metabolisable energy (ME) content showed a higher correlation (r = 0.43). However, despite this correlation, ME, like the other diet composition variables, was not a useful parameter to predict daily methane production, as indicated by the Akaike’s information criterion (AICc). Including data on concentrate supplementation at a level of 30% of the DMI did not improve the prediction of methane production. The resulting model indicated that besides DMI, bodyweight, physiological state and sex significantly affected methane production. Methane production was mostly explained by DMI. This was illustrated by the observation that when methane production is expressed per kilogram DMI (methane yield, g kg⁻¹ DMI) none of the diet or animal related characteristics showed a significant correlation with methane yield. The model performed well, but needs to be validated with an independent dataset.

For ryegrass-based pasture dry-matter intake is the single most important factor that affects methane yield, while pasture composition has no effect and animal-related factors such as physiological stage and age only appear to modulate methane emissions.

Our findings have implications for methane accounting and national inventories in pastoral agricultural systems, which account for the majority of ruminant production systems.

Antibiotics are being prohibited as additives in poultry diets. Therefore, poultry farmers have been searching for other alternatives, such as symbiotics, to include in broilers and laying hens diets. In contrast, symbiotics have not been tested in laying-type chicks, especially symbiotics composed of three groups of bacteria, yeast and two prebiotics.

This study examined the effects of replacing zinc bacitracin with symbiotic supplementation on the performance variables, haematology and blood biochemistry variables, and the weight of the immune and digestive systems in layer-type chicks.

A total of 1040 female layer-type chicks from 1 to 5 weeks of age were evaluated in a completely randomised design, four treatments and 10 replicates of 26 birds. The treatments consisted of two basal diets (one composed of corn and soybean meal [control diet] and another similar to the first diet, except with the addition of meat and bone meal [MBM]), and two diets based on MBM: one with 0.05% zinc bacitracin (ZnBc) and another with 0.1% symbiotic. Data were subjected to analysis of variance and means were compared by orthogonal contrasts.

MBM provided higher mean bodyweight, weight gain and creatinine levels, but lower liver weight, caecum length and gamma-glutamyl transferase levels than in the birds fed the control diet. From 1 to 14 days, ZnBc provided greater bodyweight and weight gain than MBM. From 1 to 28 and 1 to 35 days, ZnBc resulted in higher bodyweight and weight gain, but lower feed intake and feed conversion ratio than birds fed the MBM diet. ZnBc decreased alkaline phosphatase, and increased creatinine levels and gamma-glutamyl transferase. From 1 to 14 and 1 to 21 days, 0.1% symbiotic provided a better feed conversion ratio than in the birds fed the ZnBc diet. The 0.1% symbiotic supplementation resulted in lower liver and fabricius bursa weights, higher mean alkaline phosphatase, and lower globulin, gamma-glutamyl transferase and aspartate transferase levels than ZnBc.

The symbiotic is effective for female layer type-chicks, fulfilling the purpose of replacing ZnBc.

Symbiotics used in chicks’ diets from the first day of life can replace antibiotics to maintain physiological homeostasis and protect them from possible stress situations.

Variation in bodyweight is an undesirable feature in broiler production. Compositional differences between high- and low-bodyweight (BW) chicks in bone parameters and tissue mineral concentrations may provide insight into underlying causes of variation in BW.

This study aimed to investigate differences in bone measurements, tissue mineral concentrations, and gut parameters of Ross 308 male broiler chicks with identical diet and environmental conditions, but with distinct BW on Day 21 (D21).

A 3-week growth study was conducted involving 40 male, day-old chicks from the Ross 308 line. Chicks were reared in a deep-litter house with a controlled environment and the same commercial diet. On D21, BW data collected from chicks were used as a criterion to rank them into high- and low-BW groups (n = 11/group). Retrospective BW measurements were compared between groups. Birds were selected for assessing bone parameters, liver mineral profile, gut pH, gizzard neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents.

Retrospective BW measurements among the high- and low-BW groups showed a consistent difference in BW between the two groups in early life. Tibial concentrations of manganese and strontium were significantly (P < 0.05) higher in the low-weight (LW) group relative to the high-weight (HW) group. Concentrations of manganese, cadmium and caesium in the liver tissue showed significant differences, with the LW group having higher concentration of these trace elements. The LW chicks had lower gizzard digesta pH, higher gizzard NDF and a statistical tendency for higher ADF concentrations compared to the HW group.

In summary, broilers ranked on the basis of D21 BW showed differences in tibial bone, gut, and tissue mineral parameters. The LW group had lower gizzard pH and higher gizzard fibre content than did the HW group, which may be attributed to factors such as behavioural activities relating to more litter consumption among the LW group than the HW group.

Improved knowledge of the quality of the diet ingested by grazing cattle requires measurement of the diets selected, including in native pasture rangeland.

The goal of the present study was to develop empirical equations to predict the intake, digestibility and protein concentration of the diet selected from faecal crude protein concentration of cattle grazing heterogeneous native grasslands through seasonal cycles in the Pampa biome of southern South America.

In Experiment 1, cattle held in metabolism pens were fed native pasture at 15 and 22.5 g DM/kg bodyweight, or ad libitum. In Experiment 2, cattle also housed in metabolism pens were offered mixtures of the native pasture and Italian ryegrass at a proportion of 0.33 and 0.66 of the mixture, or pure ryegrass. Organic-matter intake (OMI), faecal crude protein excretion (fCP), faecal crude protein concentration (fCPc), OM digestibility (OMD) and diet crude protein concentration (dCPc) were measured in Experiments 1 and 2 and relationships were developed between the diet attributes and faecal crude protein (CP). In the Experiment 3, steers grazed native grasslands (NatG), or native grasslands overseeded with Italian ryegrass (NatG + RyeG). Intake and digestibility equations generated in Experiments 1 and 2 were then evaluated in Experiment 3 to estimate diet attributes from faecal protein measures.

Three non-linear models (exponential, hyperbolic and mixed, i.e. exponential + hyperbolic) were examined to evaluate the OMD. The mixed model had the highest R² value (0.74) and the lowest relative prediction error. OMI and dCPc were both linearly related to fCP. The OMD, OMI and dCPc equations were able to detect differences among diets in Experiment 3.

It was verified that the faecal CP can be used to estimate key nutritional characteristics in cattle grazing heterogeneous grasslands in the Pampa biome in South America.

Relationships between faecal CP and key diet attributes can be used to support further research and models for nutritional assessment of the diet and productivity of grazing cattle in the rangeland system examined.

Global food insecurity is mostly the result of human-animal competition for food, as well as recent population growth, erratic weather patterns and environmental shocks. Therefore, maximising the production of animal proteins can reduce the competition between demand and consumption. Hence, the current review aimed at outlining the use of hemp on the production, health and reproductive performances of farm animals. The data used in this review were accessed using Google Scholar, Science Direct, ResearchGate and the directory of open-access journals. It was found that industrial hemp, particularly its derivatives such as hemp-seed meal and oil, has gained attention for its potential benefits in animal nutrition and health. The impact of hemp on farm animals, their productivity, health and reproductive performance, is an area of ongoing research. Our findings on the assessment of the nutritional benefits of hemp to livestock have shown hemp to be a great nutritional source to livestock because, hemp-seed cake, a byproduct of hemp oil extraction, is rich in essential and non-essential amino acids, fibre, and healthy fats, including omega-3 and omega-6 fatty acids. When incorporated into animal feed, it can contribute to a balanced diet, potentially improving overall health and productivity. Furthermore, the health benefits may be due to the fatty acid profile in hemp that is known to have positive effects on animal reproduction (optimal fertility and gestation) and health, including anti-inflammatory properties, which could benefit conditions related to inflammation. Additionally, hemp contains compounds such as cannabinoids and terpenes that might offer therapeutic effects, although the effects of these compounds in animals are still being studied. In conclusion, there is limited direct research on hemp’s effect on reproductive performance in farm animals. Hence, more research is necessitated.

Commercial Pekin Ducks housed in conventional open-sided sheds often experience heat stress in summer. Electrolyte or osmolyte supplements can help birds cope under heat stress.

To assess the effects of water electrolyte/betaine supplementation or betaine in feed on the growth performance of Pekin ducks exposed to high ambient temperature.

Commercial Cherry Valley Pekin ducks were fed diets with a dietary electrolyte balance (DEB) of 160 (L-DEB) or 209 (H-DEB) over Days 15–41 (D15–41) of age. Over D36–41, ducks were provided with water alone or supplemented with betaine in the feed (BF), or betaine and an ‘in-house’ electrolyte (E) formulation at 50%, 100% or 150% (D36–41) or at 100% for only 36 h on D40–41. There were 12 treatments with four replicate pens for each treatment. On D36–41 of age, temperature was increased to 28–32°C for 9 h (from 08:30 hours to 17:30 hours) and then returned to 22–24°C for the remainder of the day. Individual liveweights were taken on D28, D35, D41. During these times, feed intake and water consumption were determined. On D41, one male and one female from each pen were weighed, euthanised and breast muscle was removed and weighed. Birds were collected for commercial processing at 04:00 hours on D42.

Over D15–35, the DEB had no effect on bird performance. Over D36–41, for liveweight gain (LWG) there were significant interactions between treatment × week (P < 0.001) and treatment × diet (P = 0.017). Supplements E150 and E100 + 36 h supported LWG more than did other treatments, while treatments BF, E50 and E100 supported higher LWG than in controls. On the L-DEB diet, the control birds had a LWG lower than in other treatments (P < 0.05). On the H-DEB diet, the E50 supplement had highest LWG, but comparable to that in E100 + 36 h. The supplements had no effects on breast muscle yield, weight losses during transport and lairage or processed carcass weights.

The electrolyte supplements supported higher LWG during exposure to moderately adverse high temperature. Supply for 36 h supported LWG equivalent or better than did other treatments given over 6 days. The benefits could be related to increased water intake and not just electrolyte supply.

Water electrolyte plus betaine supplementation supports improved Pekin duck performance during a moderately high temperature challenge.

The attitudes of stockpeople towards their animals directly affects the human–animal relationship, in turn affecting stockperson behaviour and animal welfare and productivity. Little is known about the attitudes of Australian stockpeople towards dairy youngstock under their care.

We aimed to explore Australian stockperson attitudes and management practices associated with calf management and reported replacement heifer outcomes.

A convenience sample surveying 91 Australian dairy stockpeople was used to explore common calf-rearing practices, as well as attitudes of stockpeople towards youngstock and current issues in youngstock welfare and management on Australian dairy farms.

Management of both replacement and non-replacement calves varied considerably by farm, and reported practices did not correlate with herd management or demographic data. Factor analysis identified nine principal components related to attitudes towards primiparous heifer and calf welfare and management practices. Variables calculated from these components rarely correlated with demographic factors; however, female respondents were more likely to have positive attitudes towards current issues in calf management (P = 0.013). Several correlations were found between the component variables. Participants who believed it was difficult to use higher-welfare practices to manage the herd were less likely to believe their trusted advisors valued these practices (P < 0.001), or believe these practices were important themselves (P < 0.001). These participants were more likely to believe that early lactation heifers were difficult to handle (P < 0.001), and less likely to believe that it was important to separate cows and calves for calf health (P = 0.006). Respondents who believed that heifers were difficult to handle in early lactation were more likely to believe heifers on their farm were underperforming (P < 0.001).

Factors external to farm demographics appear to shape the attitudes of Australian stockpeople and on-farm dairy youngstock management decisions. Attitudes towards youngstock appear to be linked to on-farm cultures, particularly the perceived difficulty of performing tasks linked to good welfare outcomes, and the perceived value placed on these practices by trusted advisors.

The results indicate that further research using a more representative sample is needed to better understand those responsible for Australian dairy youngstock management and the key drivers behind their management choices, to best tailor approaches to encouraging implementation of best practice on-farm.

Breech flystrike is a painful, debilitating and potentially lethal disease caused by the larvae of the blowfly, Lucilia cuprina, and, despite many years of research, it remains a serious financial and animal-welfare issue for the Merino sheep industry in Australia. The common methods of prevention, namely insecticides, crutching and ‘mulesing’, are problematical, so alternative approaches are needed. Breeding for resistance to breech strike is a fundamentally attractive proposition, but the trait itself is difficult and expensive to quantify in large numbers of sheep in extensive production systems. Several indirect traits are correlated with susceptibility to flystrike, but a large proportion of the variation in susceptibility remains unexplained. The common thread through those indirect traits is odour, so we turned to the biology of insect olfaction and its role in fly–sheep interactions. L. cuprina uses odours to detect and locate potential hosts over long distances, to guide orientation and landing behaviour, and to select egg-laying sites. Preliminary studies demonstrated the importance of confining our work to gravid female L. cuprina, and also validated the use of flies reared in the laboratory for experimentation. Using laboratory-reared flies and a combination of gas chromatography–mass spectrometry with electroantennographic detection, we identified odouriferous compounds from sheep that the antenna of L. cuprina can detect. To determine whether the identified compounds were attractive or repulsive, we needed to use a behaviour test. In preliminary studies, we compared four behaviour bioassays (Y-tube, landing time, visiting frequency, and trap) and found the trap to be the most effective. We observed that L. cuprina was attracted by several compounds in Merino wool, including octanal, nonanal and dimethyl trisulfide. We also found that the wool levels of octanal and nonanal are heritable in Merino sheep, suggesting that these compounds might be useful as traits in selection for flystrike resistance. Another possibility is that these olfactory-active compounds might guide efforts to modify the genome of sheep, or perhaps even L. cuprina. Success in these endeavours could save as much as A$200 m per year for the Australian Merino-based industries, while also improving the image of wool in world markets.

Few experiments have demonstrated how alternative fibre sources such as micronised citrus pulp in the diet of sows during pregnancy and lactation can influence the productive and biochemical parameters of the sows.

The aim of the study was to compare different fibre sources fed to sows during gestation for effects on serum biochemical and reproductive parameters, and to determine how these effects may relate to sow and piglet performances.

In total, 220 sows of average initial liveweight 240.72 ± 29.42 kg were allotted to a completely randomised design with four treatments and 55 sows per treatment. The treatments comprised different fibre sources (micronised citrus pulp, soybean hulls and coffee husks) included in the feed, with a maize–soybean-meal-based diet as the control. Productive and biochemical parameters were assessed.

Productive and reproductive performance during gestation and lactation, and litter birth weight, were not influenced (P > 0.05) by treatment. Placental efficiency (g fetus produced/g placenta) was lower (P < 0.05) in sows receiving soybean hulls than coffee husks (4.9 vs 5.4). Control sows presented lower (P < 0.05) stillborn rate than those supplemented with soybean hulls (1.08% vs 2.72%). Blood glucose, creatinine, lactate, triglycerides, total protein, cholesterol and urea were not influenced (P > 0.05) by treatment. Postprandial blood glucose and triglycerides levels were higher (P < 0.05) than preprandial levels, whereas preprandial cholesterol was higher (P < 0.05) than postprandial (67.74 vs 62.51 mg/dL).

Diverse fibre sources minimally impacted sow performance; coffee husks emerged as a potentially advantageous choice.

Nutritional strategies to enhance reproductive and productive performance can be developed by incorporating coffee husks, micronised citrus pulp or soybean hulls in sows’ feed. Use of these fibre sources did not alter reproductive and productive parameters or blood metabolites of the sows.

Porcine gametes require energy for the physiological processes that allow fertilisation. Succinate dehydrogenase (SDH) plays a pivotal role in both, the tricarboxylic acid (TCA) cycle and the respiratory chain.

The aim of this work was to study the participation of SDH in the in vitro oocyte maturation, sperm capacitation and acrosome reaction in porcine species.

Cumulus–oocyte complexes (COCs) from abattoir-derived porcine ovaries were collected by aspiration and were incubated in maturation media, with the addition of increasing concentrations (0, 1, 5 and 10 mM) of malonate (a specific inhibitor of SDH). Nuclear maturation and cytoplasmatic maturation were analysed. Semen samples were incubated for 2 h in capacitating medium with 40 mM sodium bicarbonate, as sperm capacitation inducer, and the addition of increasing concentrations of malonate (0, 1, 5 and 10 mM). Sperm capacitation state and true acrosomal reaction were evaluated. SDH activity was determined in sperm and oocyte extracts by the spectrophotometric method.

The addition of 10 mM of malonate decreased both nuclear and cytoplasmic maturation rates (P < 0.05) without affecting COC viability (assessed using fluorescein diacetate). A lower level of capacitation (induced by bicarbonate) and acrosome reaction (induced by follicular fluid) was observed with the addition of 5 mM of malonate (P < 0.05) without affecting motility and viability of sperm at this concentration. The activity of SDH was 0.35 ± 0.1 × 10⁻⁵ and 2.37 ± 0.9 × 10⁻⁵ U/COC for immature and in vitro matured COC extracts (P < 0.05) respectively, and 0.44 ± 0.16 U/10¹⁰ sperm for boar sperm extracts.

In conclusion, because it has been proposed that aerobic and anaerobic metabolic pathways of cells are changed depending on the oxygen availability and the composition of metabolic substrates in their environment, our results suggest that energy obtained through the mitochondrial respiration (TCA cycle and oxidative phosphorylation) is necessary to support oocyte maturation, sperm capacitation and acrosome reaction in the porcine species.

The study of enzymatic activity in gametes is essential for understanding the mechanisms that control the energy production required to achieve successful fertilisation. This knowledge has significant implications for the development of assisted reproductive technologies.