David Miller

This experiment examined whether multiparous sows fed a diet lower in energy and lysine at a reduced feed allowance would still mobilise fat and (or) protein to support piglet growth and negatively impact subsequent reproductive performance. A total of 152 multiparous sows was allocated in a 2 × 2 factorial design with the respective factors being diet type fed in lactation (gestation, 13.0 MJ digestible energy (DE)/kg, 0.42 g standardised ileal digestible (SID) lysine/MJ DE; or lactation, 14.3 MJ DE/kg, 0.62 g SID lysine/MJ DE) and feed allowance (ad libitum or 7.5 kg/d, ~15% reduction on ad libitum intake). Body composition was estimated on the day after farrowing (day 2) and at weaning (day 21). Blood was collected on days 2, 21 and at standing heat, for the analysis of insulin and insulin-like growth factor 1 (IGF-1). Diet type did not alter (p > 0.05) bodyweight or P2 backfat depth change in lactation, estimated body fat and protein changes, litter growth, or subsequent total piglets born. Ad libitum-fed sows showed a significant gain in girth compared to sows offered 7.5 kg/d (2.9 versus −0.4 mm, p = 0.015) and had a tendency for a shorter wean-to-service interval (p < 0.10). Sows fed the lactation diet had higher insulin concentrations at weaning (p < 0.05), but levels were the same (p > 0.10) by heat detection; IGF-1 concentrations remained unaffected. These data indicate that imposing a calculated negative energy and lysine balance on lactating sows had a limited impact on lactation or subsequent reproductive performance, supporting the notion that the modern sow may be more resilient to nutritional impositions than has been historically reported.

There is increasing interest from cattle lot-feeders in the use of shade to mitigate the effects of a potential heat stress event, though it is unclear whether the reported benefits of shade in previous studies conducted in more high-risk heat stress zones are pertinent in cooler temperate zones. The objectives of this study were to measure the welfare and performance benefits of shade provision for lot-fed cattle at a commercial feedlot located in a mild heat-stress risk zone in Western Australia. Six blocks of black Angus (Bos taurus) steers were inducted into the feedlot over six time-windows across a southern hemisphere summer, with 80 cattle per block housed in a partially shaded pen (providing 3.125 m2 of shade per animal) and 80 in an unshaded pen. Parameters assessed in 960 cattle over the first 70 days in the feedlot included weight gain, feed intake, and physiological and behavioral indices of overall health and welfare. Over the months of October through to May in which the experiment was conducted, shaded cattle demonstrated a modest 0.13 kg overall increase in average daily gain across the 70-day feedlot period (P = 0.13). There was no difference in dry matter intake between any block or treatment. The physiological and behavioral markers of health and welfare revealed that, even during to hottest times of the experiment, the cattle were quite able to thermoregulate, via increased panting and seeking shade (if available), to maintain physiological homeostasis. In addition, we measured the effect of heat stress and shade provision on the affective state of the cattle. Qualitative behavioral assessment was used to indicate that the cattle in the ‘no stress’ temperature humidity index (THI) category and the shaded cattle in the ‘moderate stress’ THI category displayed the most positive demeanor (P < 0.05), being described as more ‘settled and sociable’, while the unshaded cattle in the ‘moderate stress’ THI category and all cattle in the ‘severe stress’ THI category were described as more ‘agitated/anxious’ (P < 0.05). Overall, the findings from the present study suggest that there are definite welfare and modest performance benefits associated with providing cattle with shade in summer in a feedlot situated in a temperate climatic zone.

Farm animal welfare assessment protocols enable the capture and reporting of information to address any concerns raised by the industry or the public alike. To underpin commercial protocols, research to address validity, repeatability, and practicality, including studies to determine appropriate sampling methodology, is needed. For protocols that adopt an animal outcome-based approach, including the proposed protocol for Australian lot-fed cattle, appropriate sampling is required to ensure validity of observations. The aim of this study was to determine optimal timing and frequency of pen-side assessments. The proposed welfare assessment protocol was applied at four time points for 208 sample pens at four feedlots during a seven-month period. To determine the effect of time of day, the number of behavioural measures were reduced using Principal Component (PC) analysis, and then a Generalized Linear Mixed Model applied to consider relevant resource and environmental factors. Three primary components of cattle behaviour and demeanour were identified. PC 1 (17.61% of total variation in the observed cattle behaviour) related to activity and rest, with cattle most active at 08:00 h and 17:00 h, and least active at 14:00 h. PC 2 (10.15% variation) related to engagement with environment and feeding. At 17:00 h more cattle were observed to express positive welfare outcomes, such as engagement and feeding behaviours. PC 3 (7.07% variation) captured behaviour and demeanour that reflected cattle mental state, but minimal variation was identified related to time of day. PC 1 to 3 varied by feedlot and visit number, and PC 1 scores also differed by cattle feeding program. Results indicate that to capture variation in cattle activity and rest, repeated assessments at two key time points; early-morning and early afternoon, are required for accurate pen-side welfare assessments of lot-fed cattle. These findings suggest further refinement of the welfare assessment protocol for lot-fed cattle is recommended to facilitate commercial adoption.

Lot feeding of cattle has gained momentum in recent years to improve efficiency in meeting market demands for high quality protein. Concurrently, societal concern for the welfare of animals raised in intensive farming systems has increased. Thus, the reporting of animal health and welfare measures is a key goal for the Australian cattle lot-fed industry. Although feedlots vary in location, climate, capacity, cattle genotype, and feeding programs, many welfare concerns are applicable across the industry. Despite this, no recognised standardised animal welfare assessment protocol exists for the Australian lot-fed industry. This study aimed to identify relevant measures to develop an assessment protocol, by identifying key welfare issues and their relevant measures, considering the validity, reliability, and practicality of each when applied to the feedlot context. An advisory model was derived after reviewing the relevant literature and five international protocols for the assessment of beef cattle (Welfare Quality ® , AssureWel, US Beef Quality Assurance assessment tool, Canadian Feedlot Animal Care Assessment program, and an Australian Live Export industry protocol), followed by stakeholder consultation. A total of 109 measures were evaluated, with 99 environmental-, management-, resource- and animal-based measures being proposed. Piloting of the protocol on commercial feedlots will enable further refinement and validation, to provide an evidence-based, practical protocol to facilitate standardised monitoring of cattle welfare. Such a protocol could promote continued advances in animal welfare at a feedlot level and support a sustainable industry by addressing societal concerns.

Lamb mortality is an important economic and welfare problem for the Australian sheep industry with 20 – 30% of lambs dying before weaning, 74% within three days of birth. A significant proportion of these lamb deaths and an unknown number of ewe deaths are related to dystocia (difficult birth). This review aims to describe the nutritional and non-nutritional pathways that may affect parturition and dystocia; quantify impacts on the Australian sheep industry, and; identify both opportunities to improve lamb and ewe survival and knowledge gaps requiring research and development…

Objectives To document changes in urinary biomarker concentration and conventional diagnostic tests of acute kidney injury (AKI) following hypotension and fluid resuscitation in anaesthetized dogs. Study design Experimental, repeated measures, prospective study. Animals A group of six male adult Greyhound dogs. Methods Following general anaesthesia, severe hypotension was induced by phlebotomy, maintaining mean arterial blood pressure (MAP) < 40 mmHg for 60 minutes, followed by resuscitation with intravenous gelatine solution to maintain MAP > 60 mmHg for 3 hours. Following euthanasia, renal tissue was examined by light microscopy (LM) and transmission electron microscopy (TEM). Urinary and serum concentrations of neutrophil gelatinase-associated lipocalin (NGAL), cystatin C (CysC), and gamma-glutamyl transpeptidase (GGT), serum creatinine and urine output were measured at baseline and hourly until euthanasia. Data are presented as mean and 95% confidence interval and analysed using repeated measures analysis of variance with Dunnett’s adjustment, p < 0.05. Results Structural damage to proximal renal tubular cells was evident on LM and TEM. Urinary biomarker concentrations were significantly elevated from baseline, peaking 2 hours after haemorrhage at 19.8 (15.1–25.9) ng mL–1 NGAL (p = 0.002), 2.54 (1.64–3.43) mg mL–1 CysC (p = 0.009) and 2043 (790–5458) U L–1 GGT (p < 0.001). Serum creatinine remained within a breed-specific reference interval in all dogs. Urinary protein–creatinine ratio (UPC) was significantly elevated in all dogs from 1 hour following haemorrhage. Conclusions and clinical relevance Urinary NGAL, CysC and GGT concentrations, and UPC were consistently elevated within 1 hour of severe hypotension, suggesting that proximal renal tubules are damaged in the earliest stage of ischaemia-reperfusion AKI. Measurement of urinary biomarkers may allow early diagnosis of AKI in anaesthetized dogs. Urinary GGT concentration and UPC are particularly useful as they can be measured on standard biochemistry analysers.

Gamma-aminobutyric acid (GABA) is a non-protein amino acid, a major inhibitory neurotransmitter in the central nervous system that stimulates feed intake and inhibits the hypothalamic-pituitary-adrenal (HPA) axis. We hypothesised that: (1) GABA supplementation in the diet would reduce markers of the stress response in weaned pigs injected with adrenocorticotropic hormone (ACTH) and inoculated with enterotoxigenic Escherichia coli (ETEC); and (2) this reduction in stress responses would improve performance after weaning. A total of 96 newly-weaned male pigs (Large White x Landrace) were stratified into a two by four factorial arrangement with respective factors being (i) with/without ACTH injection and ETEC infection (challenge versus non-challenge) and (ii) four dietary GABA levels (0, 60, 80, 100 mg/kg). On days 8 and 9 after weaning, piglets were orally inoculated with ETEC (0.8 ml via two gelatinized capsules; serotype O149; F4) as well as being given 5 IU ACTH intramuscularly (IM), which occurred an hour before ETEC inoculation. Pigs in the non-challenged group were given IM 0.2 mL of sterile saline and sham infected with two capsules of PBS. Faecal consistency scores were recorded daily, pigs and feed were weighed weekly to determine performance and blood samples were collected at days 6, 9 and 14. GABA supplementation did not reduce plasma cortisol. However challenged pigs had higher levels compared to the non-challenge group at day 9 (P = 0.001). Performance was not influenced by GABA supplementation (P > 0.05). Between days 8–14, 54.3% of pigs in the challenge group developed diarrhoea compared to 5.6% in the non-challenged group (P = 0.001). These data indicate that eliciting both an ETEC infection challenge and an acute stress response after weaning initiated an endocrine stress response. The use of GABA in feed did not reduce this stress response, reduce diarrhoea or improve production performance.

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

Weaning piglets usually involves mixing of non-littermate pigs into a new environment that causes social and physical stress due to the vigorous fighting and contributes to the post-weaning growth check. Dexamethasone (DEX) is a synthetic corticosteroid shown to attenuate stress responses via negative feedback on the hypothalamic-pituitary-adrenal (HPA) axis. The hypothesis tested in this study was that DEX given before the imposition of a stressful challenge, namely mixing non-littermate pigs, would ameliorate the stress response, sustain gastrointestinal tract (GIT) function, and increase growth performance. At weaning (d0), 96 male piglets (6.5 ± 0.9 kg) were allocated into pens with their littermates (4/pen) and allowed to acclimate for 14 days, at which point they were allocated to a 2 × 2 factorial arrangement of treatments from d14 to d28 with the respective factors being (i) treatment (administration of DEX or saline; DEX v SAL) and (ii) group type (mixing of non-littermate pigs or pigs kept as littermates; MIXED v NonMIXED). The study finished on d28 after weaning. On d12 and 13, pigs in the DEX treatment were given intramuscular injections of 0.2 mg/kg DEX at 0600 h and 1800 h (total 4 doses/pig; 0.8 mg/kg), while pigs in the control treatment were given the same volume of SAL. On d14 at 0800 h, 48 pigs were mixed with non-littermates and 48 pigs remained with their littermates. Individual body weights were measured weekly, and blood was collected at 1200 h on d11, d14 (4 h after mixing), and d16. On d14 and 16, four pigs per treatment group (n = 16) were given an intra-gastric dose of a solution containing 2.5 mL/kg 20% mannitol and 0.036 g/kg Co-EDTA to test gastrointestinal permeability. Plasma cortisol was greater (P = 0.001) in MIXED pigs at both 4 h after mixing (d14) and 2d after mixing (d16). Pigs given DEX tended (P = 0.100) to have a reduced cortisol concentration at day 14 regardless of the mixing treatment. The concentration of d-mannitol in plasma was reduced (P = 0.024) in pigs dosed with DEX compared to control pigs two days after mixing (d16). Growth performance was not improved by DEX treatment during the study. These results suggest that DEX has the ability to reduce some plasma stress markers and reduced intestinal permeability, possibly due to its anti-inflammatory properties, although DEX treatment did not improve performance.