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Simple Summary: Behavioral patterns of grazing lambs associated with sickness were evaluated using a model of infusion with the endotoxin lipopolysaccharide (LPS), which can lead to subclinical symptoms of disease. Acceleration sensors are validated to have the potential to identify behavioral patterns of farm animals, which can indicate a deterioration in health. However, there is limited research on automatic identification of sickness behavior of grazing lambs. In the present study, the commercial ear-mounted CowManager SensOor (Agis, Harmelen, The Netherlands) was used to detect the changes in behavioral patterns of grazing lambs and showed promising potential for accurately identifying the sickness behavior of grazing lambs. Acute disease of grazing animals can lead to alterations in behavioral patterns. Relatively recent advances in accelerometer technology have resulted in commercial products, which can be used to remotely detect changes in animals' behavior, the pattern and extent of which may provide an indicator of disease challenge and animal health status. The objective of this study was to determine if changes in behavior during use of a lipopolysaccharide (LPS) challenge model can be detected using ear-mounted accelerometers in grazing lambs. LPS infusion elevated rectal temperatures from 39.31 °C to 39.95 °C, indicating successful establishment of an acute fever response for comparison with groups (p < 0.001). For each of the five recorded behaviors, time spent eating, ruminating, not active, active, and highly active, the accelerometers were able to detect an effect of LPS challenge. Compared with the control, there were significant effects of LPS infusion by hour interaction on durations of eating (−6.71 min/h, p < 0.001), inactive behavior (+16.00 min/h, p < 0.001), active behavior (−8.39 min/h, p < 0.001), and highly active behavior (−2.90 min/h, p < 0.001) with a trend for rumination time (−1.41 min/h, p = 0.075) in lambs after a single LPS infusion. Results suggest that current sensors have the capability to correctly identify behaviors of grazing lambs, raising the possibility of detecting changes in animals' health status. [ABSTRACT FROM AUTHOR]

Intensive pastoral systems have moved away from diverse and varied diets towards overly simple monotonous diets. Feed choice through time is an obsolete way of providing forage to animals, as intensive management schemes generally allocate a single herbage or a dyad mixed sward. Monotonous feeding regimes impose nutritional repetition, which may impair animal performance and welfare. The objective of this experiment was to determine the impact of a diverse diet [DIV; free choice from perennial ryegrass (Lolium perenne L.), plantain (Plantago lanceolata L.), alfalfa (Medicago sativa L.), and chicory (Cichorium intybus L.) at all times], a varied diet [VAR; choice from ryegrass and plantain in the AM (0700–1600 h), and chicory and alfalfa in PM (1600–0700 h)], and a single forage diet of alfalfa [SFA; alfalfa at all times], on DMI, performance, and welfare of lambs. Six-month-old Coopworth ram lambs (n = 21) were offered their respective fresh-forage treatment (n = 7) diet indoors for 20 d. The DIV lambs consumed 1.64 ± 0.03 kg DM/d (mean ± SEm), which was 6% more (P < 0.05; 1.54 ± 0.03 kg DM/d) than the SFA and were not different (P > 0.05; 1.59 ± 0.03 kg DM/d) to the VAR lambs. Average daily gain (ADG) of DIV (296 g/d) and VAR (378 g/d) was 30% and 67% greater (P < 0.05) than that in the SFA lambs (227 g/d), respectively. The VAR lambs had 28% greater (P < 0.05) ADG than the DIV lambs. Differences among treatments were detected (P < 0.05) for the proportion of the day spent conducting the following behaviors: eating, ruminating, idling, lying, and standing. In addition, the number of bouts of stereotypic behaviors recorded from the SFA lambs (13.2 ± 2.2) was 150% greater (P < 0.05) than the DIV (5.1 ± 1.0) and VAR (5.5 ± 1.0) lambs. Our results suggest that the varied diet offered can improve animal performance and welfare compared to a monotonous SFA diet. Feeding management to provide a varied diet can improve performance relative to giving lambs free choice from taxonomically diverse forage options. Moreover, performance is affected by more than the primary chemical composition of the diet consumed, but how the diet is presented through time and the herbage species and quantities of each that are consumed to reach that chemical composition. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effect of offering animals a multi forage choice (MF) of fresh herbages on dry matter intake (DMI), live weight gain, and animal welfare, in comparison with a monotonous diet of ryegrass (Lolium perenne L.). Twenty ram lambs (30.5 ± 0.9 kg initial live weight; mean ± SEM), were randomly allocated to either a diet consisting of diverse MF choice or a single forage ryegrass (SF) diet (n = 10 per treatment) for 35 d. Both diets were fed ad libitum; however, the MF diet was composed of set dry matter ratios of 24% chicory (Cichorium intybus L.), 30% lucerne (Medicago sativa L.), 25% plantain (Plantago lanceolata L.), and 21% ryegrass. The DMI of the MF lambs was 48% greater (P < 0.01) and the within animal day-to-day coefficient of variation (CV) of intake was 26% lower (P < 0.01) than the SF lambs. The average daily gain (ADG) of lambs offered the MF diet was 92% greater (P < 0.01) than the lambs offered the SF diet. The within-animal day-to-day CV of intake was negatively related to ADG (r = −0.59; P < 0.01). The MF lamb’s urinary N concentration was 30% lower (P < 0.01) than that of the SF lambs. The SF lambs spent more time (P < 0.05) exhibiting stereotypic behaviors in the afternoon and spent more time observing other animals than the MF. Overall, allocating an MF choice of fresh herbages as opposed to a single forage diet of ryegrass increases DMI and thereby animal performance, while potentially reducing urinary N excretion. [ABSTRACT FROM AUTHOR]

Background and objectives: The possibility of manipulating the immune response in lambs to the gastrointestinal nematode Trichostrongylus colubriformis to reduce production losses associated with infection was investigated. In a series of four experiments, attempts to immunize sheep via the mucosal route to modify the immune response and induce mucosal tolerance are outlined. Initially, a proof of concept study was conducted with lambs being injected with multiple doses of a somatic T colubriformis antigen without an adjuvant in the rectal submucosa and subsequently challenged with T colubriformis L3 larvae. This was followed by a dose‐response study comparing different antigen doses to identify the optimum dose of the nematode antigen for successful induction of mucosal tolerance. The final two studies were conducted to determine the larval stage specificity of the parasite antigen and the most suitable site of delivery required to stimulate mucosal tolerance. Methods: In the proof of concept study, lambs either received repeated injections in the rectal submucosa at 3 × weekly intervals with 15 µg of L3, 11 µg of L4 and 21 µg of immature adult (L5) somatic T colubriformis antigens (ANT) or not (INF) prior to infection with T colubriformis. In the dose‐rate study, antigen dose rates of 100%, 50%, 10%, 1% or 0% of the antigen concentration used in the proof of concept study were compared while the larval stage study compared antigen from either L3, L4, L5 stages or combination of all (COMB) and the route of administration study compared antigen delivery into either the rectal submucosa (RE) or sub‐cutaneous injection (SC). Results: During infection, lamb growth was improved by antigen treatment between days 21 and 42 in the proof of concept study (P =.009), for groups 10%, 50% and 100% in the dose‐rate study (P <.05 for all) and in RE in the route of administration study with no improvement observed in the larval stage study. No differences in faecal egg counts were observed (P >.05 for all). Parasite‐specific IgA and IgE showed a dose‐response (the dose‐rate study), were not affected by larval stage (the larval stage study) and were greater in RE than SC (the route of administration study). IL‐4 production following lymphocyte stimulation was greatest in COMB (the larval stage study) and RE (the route of administration study). Conclusions: Although antigen treatment improved performance, this was inconsistent and appeared to stimulate immunity rather than induce tolerance. Combined larval stages were more efficient than individual stages, and intra‐rectal administration was more effective than sub‐cutaneous. [ABSTRACT FROM AUTHOR]

Feed supply and livestock production The 4-year experiment at Canberra demonstrated the opportunities and challenges of incorporating dual-purpose crops into the production system. Since that time research into dual-purpose cropping has continued with focus including management of crops to maximise grain yield (e.g. [13]; [32]; [34]; [3]), livestock production outputs from component studies (e.g. [9]; [33]) and improving understanding of dual-purpose cropping in the larger farming system (e.g. [1]; [7]; [2]; [35]). Wool production was also demonstrated to be increased when dual-purpose crops were part of the production system, driven by higher fleece weights and increased stock numbers ([22]). Mixed farming businesses, where cropping and livestock enterprises are managed through the integration of the resources and requirements for each, are the predominant farming system of southern Australia. [Extracted from the article]

Teladorsagiosis is a major production-limiting disease in ruminants in temperate regions throughout the world and one of the key interventions in the management of the disease is the prevention of pasture contamination with Teladorsagia circumcincta eggs by ewes during the periparturient relaxation in immunity which occurs in the period around lambing. Here, we describe the immunisation of twin-bearing ewes with a T. circumcincta recombinant subunit vaccine and the impact that vaccination has on their immune responses and shedding of parasite eggs during a continuous T. circumcincta challenge period spanning late gestation and lactation. In ewes which displayed a clear periparturient relaxation in immunity, vaccination resulted in a 45% reduction in mean cumulative faecal egg count (cFEC, p = 0.027) compared to control (immunised with adjuvant only) ewes. Recombinant antigen-specific IgG and IgA, which bound each of the vaccine antigens, were detected in the serum of vaccinated ewes following each immunisation and in colostrum taken from vaccinated ewes post-partum whereas low levels of antigen-specific IgG were detected in serum and colostrum from control ewes. Antigen-specific IgG and IgA levels in blood collected within 48 h of birth from lambs largely reflected those in the colostrum of their ewes. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effect of offering animals a multiforage choice (MF) of fresh herbages on dry matter intake (DMI), live weight gain, and animal welfare, in comparison with a monotonous diet of ryegrass (Lolium perenne L.). Twenty ram lambs (30.5 ± 0.9 kg initial live weight; mean ± SEM), were randomly allocated to either a diet consisting of diverse MF choice or a single forage ryegrass (SF) diet (n = 10 per treatment) for 35 d. Both diets were fed ad libitum; however, the MF diet was composed of set dry matter ratios of 24% chicory (Cichorium intybus L.), 30% lucerne (Medicago sativa L.), 25% plantain (Plantago lanceolata L.), and 21% ryegrass. The DMI of the MF lambs was 48% greater (P < 0.01) and the within animal day-to-day coefficient of variation (CV) of intake was 26% lower (P < 0.01) than the SF lambs. The average daily gain (ADG) of lambs offered the MF diet was 92% greater (P < 0.01) than the lambs offered the SF diet. The within-animal day-to-day CV of intake was negatively related to ADG (r = -0.59; P < 0.01). The MF lamb's urinary N concentration was 30% lower (P < 0.01) than that of the SF lambs. The SF lambs spent more time (P < 0.05) exhibiting stereotypic behaviors in the afternoon and spent more time observing other animals than the MF. Overall, allocating an MF choice of fresh herbages as opposed to a single forage diet of ryegrass increases DMI and thereby animal performance, while potentially reducing urinary N excretion., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Refugia-based strategies are intended to help slow the development of anthelmintic resistance by providing a population of parasites that are not exposed to the treatment. Evidence from field studies is lacking. There is no single way to incorporate refugia into a parasite control program. There are many options available varying greatly in complexity and practicality, and none are suitable for all situations. Incorporating refugia into production systems typically requires a change in farmer mindset and greater input of time, labor, and/or technology, but is necessary to help preserve anthelmintic efficacy and promote sustainable animal production systems., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The hypothesis that increases in the concentration of the anorectic peptide leptin may be responsible for the immune-mediated reduction in feed intake (FI) during gastrointestinal parasitism in sheep was investigated. In a 2 x 2 x 2 factorial design, the first factor was age at the start of infection (5 months old v. 17 months old). The second factor was parasite infection (no infection v. administration of eighty L3 infective Trichostrongylus colubriformis larvae/kg live weight (LW) per d three times per week for 77 d). The third factor was immunosuppressive therapy with a corticosteroid (no therapy or weekly intramuscular injection of 40 mg methylprednisolone acetate/30 kg LW). Relative to their uninfected counterparts, a 20 % reduction in FI per unit LW (FI/LW; g DM/kg LW) was observed in infected non-suppressed 5-month-old lambs from 21 to 63 d post-infection (P < 0.001) but not in comparable17-month-old ewes or in corticosteroid-treated lambs or ewes (P>0.05 for all), allowing the suggestion that the anorexia was a consequence of the developing immune response. The reduction in FI/LW in 5-month-old lambs was not associated with an increase in plasma leptin concentration. Furthermore, plasma leptin concentrations were greater in corticosteroid-treated animals (P < 0.001) and in 17-month-old animals (P < 0.001), none of which displayed an infection-induced reduction in FI/LW. Plasma leptin was positively correlated with carcass fat percentage in both 5-month-old (P = 0.016) and 17-month-old (P < 0.001) animals and did not appear to provide a direct feedback mechanism that restricted energy intake. The results do not support the hypothesis that an increase in circulating leptin is directly responsible for the immune-mediated anorexia in lambs during T. colubriformis infection.