Context Accurate early prediction of growth traits is essential for guiding selection decisions and accelerating genetic improvement in livestock. In Beetal goats, 6-month body weight is an important indicator of future performance, yet estimating its genetic merit traditionally requires time-consuming and less flexible analytical methods. Aims This study aimed to evaluate the effectiveness of advanced machine learning (ML) algorithms in predicting the genetic merit (breeding value) of 6-month body weight in Beetal goats. Methods Data from 889 goats recorded over two decades (2004–2023) at the Goat Breeding Farm, Lala Lajpat Rai University of Veterinary and Animal Science, Hisar, Haryana, India, were used. The dataset included pedigree information, birth-related factors, dam characteristics and early growth records. Nine supervised ML algorithms, namely, gradient boosting machine, random forest, support vector machine, artificial neural network, Bayesian regression, Gaussian process, multivariate adaptive regression splines, sequential minimal optimization regression, and multiple linear regression were trained and tested. Model performance was compared using R2, root mean square error, mean absolute error, mean absolute percentage error and bias metrics. Key results Gradient boosting machine showed the highest predictive accuracy, yielding the greatest R2 (85.29%), and the lowest root mean square error (0.37), mean absolute error (0.28) and bias (−0.02). Random forest performed comparably well, whereas Bayesian regression and multiple linear regression produced the least accurate predictions. Six-month body weight was identified as the most influential predictor for breeding value. Conclusions Advanced ML algorithms, particularly gradient boosting machine and random forest, demonstrated strong potential for accurately predicting breeding values for 6-month body weight in Beetal goats. Implications The adoption of these ML tools can support earlier and more precise selection decisions, thereby enhancing genetic progress and improving productivity in goat breeding programs.
Context The utilization of electrical stimulation (ES) in small ruminant carcasses is less common than in beef processing facilities. Nevertheless, ES shows promise in mitigating cold shortening and improving meat quality traits in small ruminants. Aim This meta-analysis assessed how ES applied to carcasses influences meat quality parameters in sheep and goats. Methods To evaluate the effect of ES on small ruminant carcasses, two datasets were created: sheep (21 peer-reviewed publications, 53 treatment means) and goats (8 publications, 27 treatment means). The effects of ES were assessed using weighted mean differences (WMD) between stimulated and control carcasses. Heterogeneity was examined through meta-regression and subgroup analysis considering animal age, slaughter method, stimulation timing, ES duration, and ES system. Key results In goats, ES enhanced proteolysis, increasing the myofibrillar fragmentation index (5.74%; P < 0.0001) and sarcomere length (9.32%; P < 0.0001). Low-voltage ES (50–150 V) reduced pH (WMD = −0.16; P < 0.0001) and shear force (WMD = −2.29 kgf/cm2; P < 0.0001), while increasing L* (WMD = 3.02; P = 0.001) and tending to reduce a* (WMD = −1.24; P = 0.055). In sheep, medium-voltage ES (150–500 V) reduced pH (WMD = −0.06; P = 0.041) and shear force (WMD = −0.51 kgf/cm2; P = 0.046), while improving color traits: L* (WMD = 1.27; P < 0.0001), a* (WMD = 1.18; P = 0.002) and b* (WMD = 0.75; P = 0.002). Conclusion Overall, reductions in pH and shear force in both species suggest improvements in instrumental tenderness, a key determinant of sensory quality and consumer acceptance. Sheep also showed enhanced color parameters, which may increase visual appeal and marketability. Notably, ultralow-voltage ES (<50 V) applied to goat carcasses reduced pH and shear force while increasing sarcomere length, without compromising color, suggesting potential benefits at minimal energy input. Implications ES affects goat and sheep meat quality differently, indicating that species-specific stimulation protocols may be needed to optimize its benefits.
Context The body weight of cattle decreases during transport. The decrease in weight is associated with reduced gut fill, dehydration and weight loss. Cattle experience thirst and hunger during long journeys. To the best of the author’s knowledge, a systematic review and meta-analysis of factors that contribute to weight loss during transport has not been previously published. A model that predicts body weight loss in cattle during transport may assist producers understand the key drivers of weight loss and identify opportunities where body weight loss can be reduced during the journey. Aim The aim of this review is to identify factors associated with cattle live-weight loss during road transport and to develop a predictive model to assist industry stakeholders estimate weight loss. Methods A systematic review of the literature found 26 studies suitable for inclusion in the meta-analysis, based on inclusion and exclusion criteria. Moderators were initially screened using univariable multilevel meta-regression analyses. A backward selection approach was used to construct the final multivariable model, with moderators sequentially removed based on statistical significance and model fit. Key results Feed and water deprivation time (P = 0.001) and the initial body weight of the animal (P = 0.001) were significant modifiers of body weight loss. Treatment (transport or no transport) (P = 0.3744), genetic type (P = 0.3417), region (P = 0.4501), sex (P = 0.6069) and feed type (P = 0.8101) were not significant modifiers in the univariable analysis and were excluded from the final model. Conclusions Initial body weight and the duration of feed and water deprivation are significant predictors of body weight loss. Road transportation was not a significant modifier of the relationship between feed and water deprivation and body weight loss. Implications Reducing the total time that cattle are deprived of feed and water is likely to reduce weight loss during transportation. Therefore, providing cattle with ad libitum access to feed and water as close as possible to loading may help minimise weight loss. The predictive model, based on the results of the meta-analysis, can assist industry stakeholders predict cattle body weight loss for an intended journey.
Context Stocking density can impact animal welfare during livestock export voyages. Aims This study assessed selected welfare and heat stress measures for sheep housed at two allometric stocking densities (k = 0.033 and 0.042) during a voyage from Western Australia to Kuwait. Methods Merino wethers (n = 479) were loaded onto the vessel and housed in eight pens in groups of 57–66, for a 14-day voyage. Scan sampling of the number of wethers standing was conducted at 3-hourly intervals on Days 1–12 using video footage. For a subset (five per pen; ‘focal’ wethers), liveweights were recorded on Days 1 and 13, and faecal glucocorticoid metabolite concentrations were assessed on Days 0 and 13. Focal wethers had a rumen bolus inserted on Day 0 to record rumen temperature. Respiration rates (RR) and open-mouthed breathing were recorded for focal wethers three times daily. Air ammonia was measured three times daily, and faecal pad assessments were conducted daily. Key results Additional pen space decreased the number of sheep standing over the first 4 days, but stocking density had limited effect on lying synchrony. The effects of stocking density on RR were unclear, and estimates for the effects on open-mouthed breathing and rumen temperature were consistent with small effects at most. Higher wet-bulb temperature led to increased RR and an increased likelihood of breathing with an open mouth. For both rumen temperature and RR, some wethers had lower (and others higher) average values, and some displayed smaller (or greater) increases for every 1°C increase in wet-bulb temperature. Understanding how sheep differ in their rumen temperature and RR, and in their responses to hot conditions may be useful for facilitating sheep selection and management before and during voyages. Conclusions The biological cost of attempting to cope with restricted pen space was relatively low and achieved with minor behavioural changes only, but attempting to cope with the warm conditions seemed more challenging for sheep in this study. Implications This work indicates usefulness in identifying and selecting sheep that are more able to cope with hot and humid conditions for export.
Context In the context of sustainable pig production, it is essential to identify performance gaps and implement targeted strategies to reduce variability among batches and farms, thereby fostering continuous improvement and long-term sustainability of the production system. Aims This study applied a structured methodology to identify opportunities for improvement in pig production during the growing–finishing phase. Methods One hundred farms were selected on the basis of flooring type, feeder, and housing automation. Gap analysis and clustering were applied, resulting in benchmark and non-benchmark batches by the adjusted feed conversion ratio (AFCR) and mortality rate (MR), and three clusters by AFCR, namely Cluster A (≤2.23; n = 153 batches), Cluster B (2.24–2.31; n = 229), and Cluster C (≥2.32; n = 151). Management and structural data were collected by questionnaire and compared mainly among clusters. Extra feed cost and growing–finishing phase losses were estimated, and intra-cluster regression was performed. Key results Descriptively, the benchmark showed lower mortality, higher daily intake, longer intervals between batches, and larger housing capacity than did non-benchmark farms. Significant differences were observed on AFCR and mortality (P < 0.01) for Cluster A (2.21 ± 0.01; 1.69 ± 0.08%), Cluster B (2.27 ± 0.01; 2.01 ± 0.06%), and Cluster C (2.34 ± 0.01; 2.35 ± 0.10%). Cluster A presented greater cleaning and disinfection frequency, lower pig:feeder ratio (2.20 ± 0.07 vs 7.69 ± 1.13), and more experienced farmworkers (9.47 ± 3.28 vs 1.00 ± 0.20 year). In Cluster A, higher initial weight improved AFCR (−0.008 units/kg), whereas mortality worsened it (+0.026 units/%). In Cluster C, mortality was the main driver (+0.024 units/%). Compared with Cluster A, Cluster C incurred (per 1000 pigs) +$US7870 in feed cost and +$US6.6 pigs lost. Conclusions Better AFCR in pigs during the growing–finishing phase was linked to stricter hygiene, adequate feeder space, skilled staff, lower mortality, and higher starting weight at housing. Implications Identifying targeted factors within pig production systems, such as improving hygiene practices, feeder space allocation, staff training, and pig weight at housing, can reduce mortality and enhance feed efficiency, narrowing performance gaps among commercial growing–finishing farms and contributing to more responsible and sustainable swine production practices.
Context Barley grass (Hordeum spp. L.) is a pervasive annual grass weed of southern Australian crops and pastures, producing seeds that contaminate sheep carcasses and, causing weight loss and discounts at processing of affected meat and wool. Previous modelling of barley grass control highlighted effective control strategies for reducing seed banks in lucerne over 10 years. However, the impacts of weed management strategies on the productivity of lamb enterprises grazing pastures of varying infestation levels currently remain unknown. Aims This study assessed the capacity of a ex ante bioeconomic modelling approach to simulate the impacts of variable barley grass seed contamination and weed control strategies on the profitability and productivity of weaned lambs grazing a barley grass-infested lucerne pasture in southern Australia. Methods A bioeconomic model was developed by incorporating a barley grass population model, a livestock growth model (incorporating impacts of seed contamination) within an economic framework to simulate impacts of weed control strategies applied to the barley grass population. Control strategies were activated in the model at various weed densities to investigate differences in lamb production and were simulated over a 10-year period to identify optimal weed control strategies. Key results Simulating the absence of barley grass control demonstrated incursion of large losses (A$793/ha) to the lamb production system over 10 years. Economic returns tended to remain highest under integrated management scenarios at lower weed densities (≤50 seedlings/m2). Maximum profitability could be attained through strategies targeting weed fecundity, particularly at the lowest weed density (5 seedlings/m2). Conclusions Integrated management of barley grass produced the greatest economic benefit at low weed densities when control targeted seed production. The simulation of repeated mowing constrained the barley grass infestation and showed promise as a non-chemical practice for reducing seed contamination in sheep. Further field studies and development of associated model relationships will facilitate further substantiation of model outputs. Implications Results highlighted the potential for combined model frameworks to determine economic consequences of weed management in livestock grazing systems and to identify optimal strategies that maximise livestock health, welfare and production.
Context Grazing sheep on crops provides mixed crop and livestock farmers with the opportunity to utilize available feed during early winter when demand for feed typically exceeds supply from pastures. However, this practice is associated with the risk of uneven grazing of the crop, which can lead to an increased risk of yield penalty in overgrazed areas of the crop. Aim The aim of this study was to improve the uniformity of crop grazing by attracting sheep from over- to under-utilized areas of a wheat crop with strategically placed supplement feeding stations. Methods Two paddocks of wheat were grazed for 2 weeks and plots of high (H), medium (M) and low (L) grazing intensity were identified from the analysis of sheep dispersion based on GPS tracking of seven sheep in each paddock. Supplement feeding stations were then placed in half of the plots identified as low supplemented grazing intensity (LS). Sheep were then reintroduced, and the paddocks were grazed for another 2 weeks to determine whether the placement of supplement altered the grazing distribution and intensity away from the H and towards the LS relatively more than to the L areas. Crop biomass cuts and visual grazing-score measurements were taken throughout the experiment to evaluate grazing intensity and any associated yield losses. Key results There was a significant increase in the number of GPS points in the LS plots and a decrease in the H plots after the supplement was introduced. Furthermore, there was no significant difference in grazing intensity between treatment plots after the supplement stations were introduced, indicating that grazing distribution became more uniform after providing the supplement. However, the biomass and grazing score data did not confirm the GPS data, which may have been due to high variability in biomass within paddocks. Conclusions Strategic placement of supplement feeding stations (as attractants) altered sheep grazing distribution by attracting sheep from areas of high to low grazing intensity within a wheat crop. Implications Given that feeding mineral supplements is a recommended practice for sheep grazing vegetative cereal crops, placing mineral supplement stations in strategic locations should be a cost-effective method to disperse grazing pressure and improve the utilization of dual-purpose crops that are grazed at low stocking densities. However, this will depend on a reliable and cost-effective way to identify areas of low paddock utilization, such as the commercial use of GPS tracking.
Context Porcine in vitro fertilisation (IVF) efficiency remains limited by sperm quality constraints, including high polyspermy rates and suboptimal gamete preparation. Density gradient centrifugation using Percoll is widely applied to select motile, structurally competent spermatozoa; however, the impact of different gradient configurations on sperm structural and functional integrity in cooled boar semen has not been systematically evaluated. Aims To compare four discontinuous Percoll density gradient configurations (35/70%, 45/90%, 65/70%, and 90/90%) with respect to their effects on motility, kinematics, plasma membrane integrity, and acrosomal status in cooled porcine semen. Methods Semen was collected from 11 Pietrain boars, cooled, and pooled into three experimental replicates. Each replicate was processed through the four Percoll gradient configurations. Sperm motility and kinematic parameters were assessed by computer-assisted semen analysis (CASA), plasma membrane integrity by the hypo-osmotic swelling test (HOST), and acrosomal integrity by confocal microscopy using FITC-conjugated Pisum sativum agglutinin (FITC-PSA). Key results The 35/70% gradient yielded the highest pellet concentration, whereas the 90/90% configuration produced significantly lower sperm recovery. Total motility and velocity parameters (average path velocity (VAP), curvilinear velocity (VCL), straight-line velocity (VSL)) did not differ significantly across gradients, although beat-cross frequency decreased consistently after all Percoll treatments. Plasma membrane integrity was significantly reduced in all gradient-processed groups relative to the control; the 90/90% configuration showed the lowest values. The 35/70% gradient best preserved acrosomal integrity, with intact acrosome rates comparable to unprocessed semen, whereas the 65/70% and 90/90% configurations were associated with increased acrosomal defects and spontaneous acrosome reaction. Conclusions Increasing Percoll gradient density does not improve sperm kinematic parameters but progressively compromises plasma membrane and acrosomal integrity. The 35/70% configuration provided the most favourable balance between sperm recovery and structural preservation. Implications: These findings provide practical guidance for optimising sperm preparation in porcine IVF systems, supporting the use of moderate-density Percoll gradients to maintain structural sperm integrity while ensuring adequate functional selection.
Context Increasing use of genomic information in the genetic evaluation of livestock has stimulated interest in analyses combining data from multiple breeds. This can increase the size of the reference population and increase the accuracy of predicted breeding values. In particular, it is relevant for breeds with small numbers of records that are genetically similar to the other breeds in the analysis. Aims Evaluate the scope for multi-breed genetic evaluation of tropically adapted beef cattle in Australia. Methods Data comprised records for 25 traits measured for three breeds of tropically adapted Australian beef cattle, namely Brahman, Droughtmaster and Santa Gertrudis. After quality control and edits, allele counts for 75,932 genomic markers were available for 68,200 individuals. Univariate analyses were performed fitting standard BREEDPLAN models accounting for the genetic differences among the base populations for different breeds by fitting metafounders. Estimation of variance components was followed by single-step best linear unbiased prediction analyses performed considering all records or omitting records on the youngest individuals, so-called focal animals. Contrasting results from ‘part’ and ‘whole’ analyses allowed calculation of the linear regression (LR) statistics proposed for the validation of predicted breeding values. Key results Comparing LR statistics from single- and multi-breed analyses clearly demonstrated the gains in information possible from utilising records for closely related breeds. Whereas there were only small differences for Brahman, increases in population accuracy were consistent for Droughtmaster, amounting to 0.065 on average across traits. Corresponding gains for Santa Gertrudis were, on average, 0.032, with values being close to zero for traits with many records. Conclusions Owing to crossbreeding with Brahman in creating the Droughtmaster and Santa Gertrudis breeds, the three tropically adapted breeds are sufficiently similar genetically for simple, joint multi-breed analyses prediction of breeding values to be advantageous, in particular for Droughtmaster. Implications Multi-breed analyses can increase the accuracy of genomic evaluation and enlarge the pool of selection candidates for individual producers.
Context Ammonia (NH3) production and manure pad characteristics are important animal welfare considerations for intensively housed livestock, such as those on-board livestock export vessels. Aim This study investigated the effects of five allometric stocking densities (k = 0.030, 0.033, 0.037, 0.042 and 0.047) on manure pad formation, air NH3 concentrations, lying behaviour and liveweight of Merino wethers under thermoneutral conditions. Methods Wethers were group housed in 10 respiration chambers for 21 days, across two runs. Air NH3 was measured at eight heights twice daily. Daily visual assessments of faecal pad condition, depth and moisture were conducted. Pad samples were collected from each chamber on Days 7, 14 and 21 for analysis of pH, electrical conductivity, ammonium and bulk density. Pad depth was measured at 25 locations per chamber on Day 21. Sheep standing and lying behaviours were recorded every second day at 15-min intervals, and liveweights were measured at the start and end of the voyage. Key results Lower stocking densities resulted in fewer sheep standing and reduced mean NH3 concentrations compared with the highest density. Stocking density had minimal effect on liveweight. The air NH3 concentrations measured at 5 and 215 cm from the surface of the manure pad were slightly lower than at the other heights. Pad depth increased with higher densities, whereas pads were drier at the lowest density. Pad ammonium concentration and pH were higher at the lowest stocking density, with little variation across pad depths or locations. Conclusions Reducing stocking density improved manure pad conditions and reduced air NH3 concentrations under thermoneutral conditions. Implications These findings suggest that manipulating stocking density could complement ventilation strategies to manage air quality and pad conditions in intensive sheep housing systems, including livestock export vessels and feedlots.
Context Consumption of water with high sulfate concentrations can negatively affect on feed intake in beef cattle. However, limited information is available on how water quality interacts with diets differing in digestibility. Aim This study evaluated the interaction between a broad range of diet quality (DQ) and water quality (WQ) on feed and water intake (WI), total tract digestibility, nitrogen (N) metabolism, and ruminal hydrogen sulfide (H2S) production in beef heifers. Method Eight Braford-crossbred heifers (326 ± 34 kg BW) were used in an eight-treatment crossover design combining two types of WQ, namely, low-sulfate water (LSW; 333 mg/L sulfate, SO4) and high-sulfate water (HSW; 3286 mg/L, SO4) with four DQ of low (LQ), medium–low (MLQ), medium–high (MHQ), and high (HQ). Key results A significant DQ × WQ interaction was observed for WI (P = 0.04), digestible organic matter (OM) intake (DOMI; P = 0.01), and digestible neutral detergent fiber (NDF) intake (DNDFI; P < 0.01). Diet quality had a quadratic effect on both water (P = 0.02) and feed intake (P < 0.01), with the highest values occurring at intermediate levels of digestibility. High-sulfate water reduced WI (P < 0.01), OM intake (OMI; P < 0.01), and NDF intake (NDFI; P < 0.01). In heifers consuming HSW, DOMI tended to be lower at the highest DQ (HQ; P = 0.07), with lower values also observed at intermediate DQ levels (MLQ and MHQ; P < 0.01). Water quality improved and tended to enhance total tract NDF (P = 0.03) and OM digestibility (P = 0.06) respectively. High-sulfate water also increased ruminal H2S concentrations (P < 0.01). Conclusions The results of this study demonstrated an interaction between diet and water quality affecting feed intake in beef heifers. Implications Improving diet quality may help mitigate the negative effects of high sulfate-containing water on feed intake. Additionally, incorporating highly digestible NDF into the diet appears to be a viable strategy to maintain ruminal H2S concentrations below toxic thresholds.
Early life programming has been recognised as a potential enteric methane mitigation strategy. The premise is that the rumen microbiome of the young ruminant is malleable, thereby allowing for intervention to tailor the rumen environment to produce animals with life-long low methane emissions. This review explores the potential to affect the developing ruminal microbiome at different life stages. Exposure to external factors during the pre- and post-weaning stages have been shown to influence ruminal microbial populations with varying duration post-birth, with careful management required to sustain microbial changes for low enteric methane emissions. There is growing evidence that indicates the presence of gastrointestinal tract microbes in the neonatal calf. Interventions aimed at manipulating the ruminal microbiome should be considered as early as, or even prior to, conception. However, the sensitivity of the rumen microbiome to changes in the environment and life stage means that it is currently not a viable methane mitigation solution for the Australian dairy industry, where most enterprises are pasture-based systems. We recommend that future research places an emphasis on understanding the longevity of microbiome changes in young ruminants. Such research would provide valuable insights into the efficacy of early life programming as a methane mitigation strategy on Australian dairy farms and potentially provide a platform to stack shorter-term mitigation strategies to maximise abatement over the life of the cow.
Ram sperm cryopreservation is crucial for artificial insemination and genetic improvement programs in the small ruminant industry. Semen handling and cryopreservation can negatively affect sperm quality irrespective of the storage conditions and extenders used. Studies have reported an increase in reactive oxygen species in ram sperm during cryopreservation, leading to oxidative stress. Oxidative stress significantly compromises the sperm fertilising ability by inducing oxidative damage to protein, lipid, and nucleic acid components of the sperm cell. The supplementation of antioxidants to semen extenders before cryopreservation can minimise this detrimental effect. Natural antioxidants have emerged as an economical and effective source of additives to preserve and enhance ram sperm quality during semen preservation. This review presents an overview on harmful effects of oxidative stress on ram spermatozoa, extrinsic and intrinsic factors responsible for occurrence of oxidative stress, as well as natural antioxidants and their potential as an additive for sperm quality enhancers in different ram breeds. Taken together, we suggest that synergistic combinations of antioxidants that are economically feasible, such as resveratrol with vitamins C or E, could be the way forward, but warrant further investigations into dosage versus toxicity, standardised extraction protocols, and breed-specificity in their supplementation in semen extenders.
Context Industrial hemp biomass, the low Δ9-tetrahydrocannabinol variety of Cannabis sativa L., was identified as a potential feed for ruminants because of its quick growth rate and high biomass yield. Industrial hemp biomass was found to be nutritionally suitable for sheep following feeding either iHemp stubble- or hay-containing diets; however, the potential effects the cannabinoids present in industrial hemp biomass, including both Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD), may have on the consuming animal remain largely unknown. Aims The aim of this study was to determine whether Δ9-THC and/or CBD are metabolised in the rumen, affect the rumen environment, and/or the 24 h digestibility of a feed standard. Methods Daisy™ incubators designed for the efficient laboratory simulation of ruminant digestion in vitro were utilised, with the study consisting of three treatment groups (1, dimethyl sulfoxide (DMSO) only; 2, CBD and DMSO; and 3, Δ9-THC and DMSO), and four replicates per treatment. Over a 24 h incubation period, the incubation medium was sampled to determine diurnal cannabinoid concentrations and volatile fatty acid (VFA) concentrations and molar proportions. At the end of the incubation period, the incubated lucerne hay standard was analysed to determine 24 h digestibility. Key results There was no evidence that either Δ9-THC or CBD are metabolised by ruminal microorganisms. Mean total VFA concentrations were unaffected; however, dry matter, organic matter and crude protein 24 h digestibility were all decreased following addition of either Δ9-THC or CBD to the incubation medium. Conclusions Metabolism of the cannabinoids must occur in an alternate location in ruminants, such as the liver, with further research required to confirm. Both Δ9-THC and CBD exert an adverse effect on digestibility, which has implications for iHemp to be a feed for production animals. Implications If industrial hemp is to be a feed for ruminants, more research is required to determine maximum concentrations of cannabinoids that ruminants could consume without causing any adverse effects on the animal, their microbial populations and, consequently, production characteristics.
Nutrition is the foundation of life and yet, resources are finite. For wild animals, variation in resources and risk across time and space has resulted in a wide array of adaptations that allow individuals to meet daily metabolic and nutritional needs, including seasonal changes in metabolism, capital stores, and diverse reproductive strategies. For long-lived, iteroparous mammals, resources should be obtained, allocated, and stored in a way that balances current needs and yet, is sensitive to future requirements for survival. We propose that risk-sensitive allocation of energy is the mark of a nutritional legacy associated with an anticipatory adaptation of seasonal and variable environments. Here, we synthesize how nutritional legacies are interwoven into the very existence and life history of large ungulates, and how the accumulation of nutritional legacies across lifetimes and generations emerges into a nutritional ecotype. We describe nutritional ecotypes as the integrated profile of how large ungulates anticipate, acquire, store, and allocate energy across temporal scales, from daily decisions to evolutionary history. The annual fat cycle of ungulates, although affected by environmental conditions, is an anticipatory outcome of risk-sensitive allocation of resources anchored in metabolic programming within the context of a specific environment and the life history of a species or sex. Refinement in risk-sensitive allocation across days, seasons, lifetimes, and generations yields an important life-history adaptation that enables animals to align resource acquisition and allocation with the specific environments they occupy. Energetic strategies of wild animals are both a product of past experiences and the anticipation of the risks and resources that will occur in the future; the shaping of a nutritional ecotype in wild ungulates is itself an adaptation to local environments. We contend that further appreciation for nutritional ecotypes holds potential to advance our understanding of how large ungulates will persist or fail to, in our ever-changing world.
Context The drinking water temperature during winter has a significant impact on dairy buffaloes’ thermoregulation, which in turn influences their haemato-biochemical, endocrine responses and milk yield. Aims The experiment was conducted to find out the effect of drinking water temperature on haemato-biochemical and endocrine responses of lactating Murrah buffaloes during the winter season under a subtropical climate. Methods Twenty-four lactating buffaloes maintained at Livestock Research Centre, ICAR-National Dairy Research Institute, Karnal, India, under a loose housing system were selected for the study during January to March 2024. Twenty-four lactating buffaloes were divided into three uniform/random groups, with eight in each group after considering their bodyweight, parity and milk yield. Group-I animals were offered drinking water at a temperature of 8–12°C, whereas, Group-II and Group-III were offered drinking water at temperatures of 20–24°C and 32–36°C, respectively. Voluntary water intake was recorded daily and blood sample analysis was conducted at fortnightly intervals. Serum biochemical and endocrine parameters, including glucose, total protein, albumin, blood urea nitrogen, creatinine, cholesterol, triglycerides, insulin, non-esterified fatty acids and total antioxidant capacity were analysed. Key results The study revealed that the group offered cold water had significantly (P < 0.05) less water consumption. The results revealed that drinking water temperature did not significantly affect the haematological profile, but significantly influenced electrolyte balance, metabolic responses and stress indicators. Cold water (8–12°C) significantly increased blood glucose, non-esterified fatty acids and electrolyte concentrations, indicating higher metabolic demands and mild stress. Whereas fresh water (20–24°C) and warm water (32–36°C) promoted efficient glucose metabolism and retained lower insulin concentrations while boosting antioxidant capacity. Conclusion The present study indicated that fresh water temperature (20–24°C) was sufficient in maintaining metabolic efficiency, reducing the effects of cold stress in buffaloes, and promoting better health and performance without the cost of suppyling heated water. Implications The study draws attention to a simple, yet efficient management approach that might enhance animal welfare and health during severe winters.
Context Recently, there has been a growing global and local demand for goat meat. However, various extrinsic and intrinsic factors can influence goat meat production. Aims This study investigated how goat breed affects carcass characteristics and meat-quality parameters. Methods Twenty-four goats, consisting of Boer goats (BG), Rangeland goats (RG), and their first-generation crossbreds (F1), of similar age and sex, and raised on the same property, were weighed and electrically stunned before being exsanguinated. Weight ratios of by-products, including head, trotters, heart, liver, kidney, lungs, testicles, skin, and gastrointestinal tract (GIT), to liveweight were calculated to determine yield. Carcasses were broken into commercial cuts, where each cut underwent deboning, after which lean yield, fat, bone, and the lean-to-fat ratio were assessed. The following six muscles were collected for further analysis: longissimus thoracis et lumborum (LTL), semimembranosus (SM), biceps femoris (BF), semitendinosus (ST), infraspinatus (IS), and supraspinatus (SS). The measured quality parameters included pH, color, moisture, protein, fat, and ash content. Key results The liveweight, carcass, head, and skin weights were heavier (P < 0.05) in BG than in the other breeds. The yield of the flap cut was significantly higher in BG (3.58%) and RG (3.54%) than in F1 (3.24%). The BG breed had a significantly higher lean-to-bone ratio for the loin than did the F1 breed. However, there was no difference in the total lean-to-bone ratio between BG and RG or between RG and F1. The muscle color of RG had significantly higher a*, b*, and chroma values than did BG for both the BF and SS muscles. Moreover, breed did not differ significantly in moisture or protein content, whereas fat content was significantly higher in the ST and IS muscles from RG than from F1. Conclusions The goat breed significantly influenced carcass yield and some meat-quality attributes. The BG breed exhibited higher meat yield than did other breeds. Implications These findings suggest potential advantages for producers when breeding with more meaty breeds, because breed differences in carcass characteristics and meat-quality traits offer opportunities for targeted breed programs and market differentiation.
Chronobiology is the science of how organisms maintain synchrony with rhythmic variation in their natural environment. Over the past five decades, research in a select group of species has led to a consensus that daily synchrony is maintained via genetically encoded, innate circadian timer systems, which are a ubiquitous property of life. The current understanding of how year-round seasonal synchrony is achieved is, by contrast, less well developed and the role of innate circannual timers is a matter of continuing debate. Here, we consider how the behaviour and physiology of cervids is temporally organised, and the extent to which chronobiological principles usefully apply in this group. We also consider the contributions of deer biology to our understanding of chronobiology. Internal temporal programs emerge as the hidden masters of animal responses to changing energy demands throughout the year. Prospectively, understanding of these temporal programs is important or developments in farming and maintaining healthy biological synchrony in a changing world.
Context Rusa deer (Rusa timorensis) is classified as vulnerable because, despite being a common species in the Indo-Pacific region, its population is declining because of habitat loss and illegal hunting. Consequently, breeding Rusa deer in other regions of the world may play an important role in reducing the risk of extinction. Aim This study aimed to describe the application of B-mode and Doppler ultrasonography to evaluate the testis and accessory sex glands of this species when raised in north-eastern Brazil. In addition, seminal parameters were characterized. Methods The experiment was conducted between July and September of 2023 and 2024 by using eight adult male Rusa deer aged 42 and 60 months. Body measurements and testicular biometry were recorded. The B-mode and spectral Doppler ultrasonography of accessory genital glands and testis were performed. Semen was collected by electroejaculation, and kinematic parameters were determined using a portable computer-assisted sperm analysis system. Comparisons of means and proportions were performed using the independent t-test and Fisher’s exact test respectively, with statistical significance set at P < 0.05. Key results The seminal vesicles were visualized in all experimental animals and the mean (±s.d.) echogenicity was 55.15 ± 23.20. The prostate was located dorsal to the urethra, with the body and disseminated parts being clearly defined and exhibiting a homogeneous echotexture. When comparing supratesticular and iliac arteries, significant differences were observed for end-diastolic velocity (EDV), time-averaged maximum velocity (TAMAX), and pulsatility index (PI). All observed seminal parameters were similar to those reported in previous studies of Rusa deer semen. Conclusion Slightly smaller in body size, male Rusa deer raised in the north-eastern Brazil exhibited andrological and seminal characteristics similar to those of individuals in their native range. In addition, the use of B-mode and Doppler ultrasound has been shown to be an important tool in examining the genital system. Implications These findings will be useful for selection of better breeders and for the development of protocols for semen cryopreservation and artificial insemination (AI) in this species.
This paper reflects on my contributions to the fields of large herbivore ecology, conservation, and land management over the past 45 years. Although the work spans diverse ecosystems and species, a unifying thread is the pioneering research on cervids. Here, I trace my progression of thought, including shifts in focus, challenges encountered, and the influences that shape my trajectory from foundational studies on the behavioural ecology of native red deer in the Scottish Highlands to the pivotal investigations into the ecological impacts and niche shifts of invasive deer in Australia and lately the design of future deerscapes in New Zealand. I further examine how the empirical findings informed broader, pragmatic contributions to conservation policy, particularly my co-authored wolf reintroduction proposal and my influential ‘rewilding lite’ framework. By bridging empirical science with a nuanced understanding of socio-economic and political contexts, my work demonstrates a crucial interdisciplinary approach to addressing complex human–livestock–wildlife conflicts. I would like to think that I have contributed to translating granular ecological data into evidence-based solutions for managing ecosystems in a human-dominated world and hope to influence the path of next generation scientists, farmers, and wildlife managers.
