lasalocid and acetoacetic-acid

Dairy calf weaning results in blood ketone concentrations in excess of mature rates of use and can result in excretion of ketones in urine representing a loss of energy. Lasalocid is frequently supplemented as an anticoccidial agent in calf starters; however, in mature ruminants it is known to alter molar ratios of ruminal volatile fatty acids (VFA). Effects of weaning transition and postweaning ionophore supplementation on body weight, dry matter (DM) intake, average daily gain (ADG), and blood concentrations of glucose, acetoacetate, beta-hydroxybutyrate (BHBA), lactate, pyruvate, nonesterified fatty acids (NEFA), VFA, insulin, and glucagon were examined using Jersey bull calves (n = 24) over 16 wk. Calves were blocked into groups of 2 according to birth date and weight and randomly assigned to receive either a commercial pelleted starter (control), or the same diet containing lasalocid (TRT; 83 mg/kg of DM). Calves were fed milk replacer from d 3 to 34 (d 3 to 20 = 454 g/d at 12% solids; d 21 to 34 = 568 g/d at 15% solids), from d 35 to 48 calves received both replacer (d 35 to 41 = 454 g/d; d 42 to 38 = 227 g/d) and free access to control or TRT starter, and from d 49 to 112 received ad libitum control or TRT. Body weight and jugular blood metabolite concentrations were measured and recorded weekly. Postweaning DM intake, average daily gain, and feed:gain did not differ between control and TRT calves. Glucose and NEFA concentrations did not differ between control and TRT, but declined with age. Insulin and glucagon concentrations did not differ between control and TRT, but glucagon concentrations increased with weaning. Total VFA significantly increased following introduction of solid feed at d 35 in both groups with an apparent 1-wk lag in TRT VFA increases compared with control. Jugular acetate and butyrate concentrations were greater in control calves than TRT calves during wk 7. Propionate concentrations did not differ between control and TRT at any time following weaning. Blood BHBA concentrations were greater in control than TRT during wk 8 and 9. Thus, consumption of starter supplemented with lasalocid delayed peak acetate and butyrate and lowered peak BHBA concentrations. However, supplementation at concentrations currently recommended for control of coccidiosis did not appear to be sufficient to enhance growth or efficiency during the wk 7 to 16 postweaning interval for this sample size.

Topics: 3-Hydroxybutyric Acid; Acetoacetates; Animal Feed; Animals; Blood Glucose; Cattle; Dairying; Diet; Eating; Fatty Acids, Nonesterified; Fatty Acids, Volatile; Glucagon; Insulin; Ionophores; Lactates; Lasalocid; Male; Models, Statistical; Pyruvates; Random Allocation; Time Factors; Weaning; Weight Gain

Two adult sheep, A and B, received successively during three experimental periods a forage-based pelleted feed, then the same diet supplemented with 33 mg/kg of lasalocid (L) or cationomycin (C). The feed was given in either eight (sheep A) or two (sheep B) daily meals. After four weeks of adaptation, 11 blood samples were taken through catheters in the rumen vein (RVA) and the mesenteric artery (MAA) in sheep A and in the rumen vein (RVB) and portal vein (PVB) in sheep B over a 5-hour period after the morning meal. Because of a blockage in the catheter it was not possible to measure the effect of C in MAA. Food intake had no immediate effect on the plasma levels measured: the distribution of eight daily meals stabilized plasma levels and made it easier to determine the effect of the ionophores. This effect varied according to the sampling site, the animal and the antibiotic, sometimes contradictorily. All the plasma parameters monitored in RVA were significantly modified by either one of the ionophores. A decrease in plasma albumin concentration (P < 0.05) was observed with L in MAA and with C in RVA and MAA. Aceto-acetate concentration decreased (P < 0.05) with L in MAA but increased with L and C in RVB. A decrease in glycaemia and uraemia (P < 0.05) was observed with L in MAA, RVA and RVB and with C in RVA. Total amino acid concentration decreased (P < 0.05) with C in RVA or increased (P < 0.05) with L in PVB and RVB. These variations in results may be due to different mechanisms of action of L and C on digestion, particularly in the rumen. While the changes undergone by the ketone bodies in the blood suggested a decrease in hepatic ketogenesis with L, there was no evidence that the ionophores had a direct postprandial effect.

Topics: Acetoacetates; Animal Feed; Animals; Anti-Bacterial Agents; Blood Glucose; Blood Urea Nitrogen; Fatty Acids, Nonesterified; Furans; Hydroxybutyrates; Kinetics; Lasalocid; Mesenteric Arteries; Portal Vein; Rumen; Serum Albumin; Sheep; Time Factors; Urea; Veins

Twelve Holstein bull calves were ruminally cannulated at 5 d of age and assigned to 0 or 1 mg of lasalocid/kg of BW daily, administered postruminally via milk replacer or into the ruminal cannula. Calves were fed milk replacer for 8 wk and calf starter for 12 wk. Lasalocid administration was terminated at weaning in calves fed lasalocid in milk replacer. Ruminal pH tended to be higher in calves fed lasalocid ruminally than in calves on control treatment and averaged 5.9 and 5.6 and 5.4 and 5.1 during wk 1 to 8 and 9 to 12, respectively. Molar proportion of ruminal butyrate tended to be lower when lasalocid was added to the rumen, particularly after weaning. Blood beta-hydroxybutyrate and acetoacetate were lower when lasalocid was administered into the rumen after weaning and averaged .897 and .646 and .026 and .015 mM in calves on control and ruminal treatments, respectively. No effects of lasalocid administered via the milk replacer were observed, except for plasma NEFA, which were reduced postweaning. These data suggest that lasalocid reduces blood beta-hydroxybutyrate by changes in ruminal fermentation and subsequent metabolism of butyrate by ruminal epithelium.

Topics: 3-Hydroxybutyric Acid; Acetoacetates; Animals; Butyrates; Butyric Acid; Carboxylic Acids; Cattle; Fatty Acids, Nonesterified; Hydrogen-Ion Concentration; Hydroxybutyrates; Ketones; Lactates; Lactic Acid; Lasalocid; Male; Rumen