The innate immune stimulant Amplimune® is safe to administer to young feedlot cattle.

BACKGROUND: Infectious disease has a significant impact on livestock production. Availability of alternatives to antibiotics to prevent and treat disease is required to reduce reliance on antibiotics while not impacting animal welfare. Innate immune stimulants, such as mycobacterium cell wall fractions (MCWF), are used as alternatives to antibiotics for the treatment and prevention of infectious disease in a number of species including cattle, horses and dogs. This study aimed to evaluate the safety of Amplimune®, an MCWF-based immune stimulant, for weaner Angus cattle. METHODS: On day -1 and 0, sixty mixed-sex Angus weaner cattle were transported for 6 h before being inducted and housed in a large single pen, simulating feedlot induction conditions. The cattle were assigned to one of six treatment groups (n = 10 per group): 2 mL Amplimune intramuscularly (2IM); 2 mL Amplimune subcutaneously (2SC); 5 mL Amplimune intramuscularly (5IM); 5 mL Amplimune subcutaneously (5SC); 5 mL saline intramuscularly (SalIM) and 5 mL saline subcutaneously (SalSC) on day 0 following transportation. Body temperature, body weight, concentrations of circulating pro-inflammatory cytokines (TNFα, IL-1ß, IL-6 and IL-12) and haematology parameters were measured at various times up to 96 h post-treatment. RESULTS: No adverse effects from Amplimune treatment were observed. Amplimune induced an increase in circulating cytokine TNFα concentrations, total white blood cell count and lymphocyte counts indicative of activation of the innate immune system without causing an excessive inflammatory response. CONCLUSIONS: Results confirm that Amplimune can be safely administered to beef cattle at the dose rates and via the routes of administration investigated here.

The use of sodium hyaluronate in freezing media for bovine and murine embryos.

Four experiments were designed to determine whether sodium hyaluronate (SH) may be used to replace newborn calf serum (NCS) in murine and bovine embryo freezing media. A total of 780 mouse and 178 cattle embryos were frozen. Freezing media were prepared in Dulbecco's phosphate-buffered saline supplemented with 20% NCS and 10% glycerol (v/v) (medium A). In experiments I and II, NCS was replaced by 0.1% SH (w/v) in medium B and by 0.1% polyvinyl alcohol (PVA) (w/v) in medium C. In experiments III and IV, NCS was replaced in mouse embryo freezing medium by three different molecular weights of SH as follows: 0.1 or 0.2% (SH-1; < 3 x 10(5) Da) in medium B, by 0.1 or 0.05% (SH-2; 5-7.5 x 10(5) Da) in medium C, and by 0.1 or 0.025% (SH-3; > 1.2 x 10(6) Da) in medium D. Embryos were frozen and thawed using standard procedures. Glycerol was diluted from embryos after thawing in a single step with 1.0 M sucrose. After 48 h in culture (Ham's F-10 medium for cattle embryos and BWW medium for mouse embryos), embryos were evaluated for development to expanded or hatched blastocysts. Survival rates were compared by chi 2 analysis. In experiment I, there were no significant differences in mouse embryo survival or development between NCS, SH, and PVA groups (84.1, 79.2, and 83.3%, respectively). In experiment II, there were no significant differences in bovine embryo survival between NCS and SH groups (67.2 and 67.7%), but both had significantly higher survival than the PVA group (37.9%; P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)