Predicting optimal time of insemination in cows that show visual signs of estrus by estimating onset of estrus with pedometers

An experiment was designed to estimate the optimal interval from the beginning of estrus to artificial insemination (AI). The data were analyzed by means of a mathematical model. The analysis was based on pedometer readings and results of rectal palpation at 42 to 49 d post-AI of 171 breedings in 121 cows. The chance of conception was highest between 6 and 17 h after increased pedometer activity; the estimated optimum was at 11.8 h. In this data file, the effects of disease, inseminator, time of AI (a.m. or p.m.), and bull did not contribute to the improvement of the model. The effects of disease were not significant because of the low incidence of any specific disease. Activity measurements can be used as a tool for AI strategy to improve conception in groups of healthy cows and heifers already showing visual signs of estrus.     

The impact of dietary cation anion difference (DCAD) on the acid-base balance and calcium metabolism of non-lactating, non-pregnant dairy cows fed equal amounts of different anionic salts

We evaluated the impact of the dietary cation-anion difference (DCAD) on the influence of anionic salts (AS) on the metabolism of dairy cows using a study-design that included control of feed intake. Ten mature, non-lactating, non-pregnant, Holstein-Friesian-crossbreed cows received 2000 mEq of either one of the seven anionic salts tested, two combinations of the anionic salts or water as control via a rumen cannula. Salts and controls were assigned in a 10x10 Latin square design. Whole blood, serum and urine samples were taken during treatment (TP) and washout period. Samples of whole blood were tested for pH, base-excess and bicarbonate concentrations. In urine, pH and net acid-base excretion (NABE) were analysed. Calcium was measured in serum and urine. According to the different batches of hay, five groups of DCAD were created regarding cluster analysis. Changes in urine and blood parameters were statistically analysed for each DCAD group separately. The different DCAD had an impact on the amount of change in acid-base balance (ABB) and calcium metabolism and for how long these changes lasted. In the DCAD group receiving the highest amount of AS (239 mEq/kg dry matter with AS), changes of ABB were only noticeable in urine and these changes only differed from day zero in the first week of TP (P<0.05). In the other four groups changes of ABB were also visible in blood parameters, but only on a few days of TP did the deviations differ significantly (P<0.05) from day zero. Changes of ABB parameters in urine samples were more pronounced than those in blood and differed clearly from day zero (P<0.05). Parallel to the changes of ABB, calcium concentrations in these samples were significantly increased (P<0.001) in all DCAD groups. Except for the highest DCAD group, ionized calcium concentrations changed over time (P<0.020). However, the differences were very small and only differed from day zero on a few TP days. We conclude that the DCAD of a dairy cow's diet has an important impact on the effect of AS on ABB and calcium metabolism with respect to the duration and amount of change. The target regions of DCAD should be clearly below 100 mEq/kg dry matter to ensure the desired effect on ABB and calcium metabolism. Extremely negative DCAD should be avoided to minimize the risk of clinical acidosis induced by AS.     

Impact of Lauric Arginate Application Form on its Antimicrobial Activity on the Surface of a Model Meat Product

This study evaluated the antimicrobial effect of N^α‐Lauroyl‐L‐arginine ethyl estermonohydrochloride (lauric arginate), sodium lactate, and sodium diacetate at various concentrations against Listeria innocua, Escherichia coli C600, and Lactobacillus curvatus (10² CFU/g) on “Lyoner style” sausage slices as a function of application form. We want to investigate if the results of a surface application of lauric arginate in various applications forms may differ from that of an in‐matrix application since different physicochemical processes occur at surfaces than in matrices. Lauric arginate was applied on the surface of meat emulsions as aqueous solution, as oil‐in‐water emulsion, and as solid lipid particles. The sausages slices were stored at 6 °C for 24 d and bacterial growth was assessed every 3rd day. The growth of L. curvatus was not impacted by lactate and diacetate at any tested concentration. In contrast, L. innocua and E. coli were inhibited over 24 d in the presence of ≥3.0 × 10³ μg/g diacetate. Aqueous lauric arginate solutions of 2.0 and 2.5 × 10³ μg/g were required for total inhibition of L. curvatus and L. innocua, respectively. The growth of E. coli was not affected by application of lauric arginate. The use of lauric arginate in an oil‐in‐water emulsion or solid lipid particles reduced antimicrobial effectiveness on the surface of Lyoner slices, which is in stark contrast to a previously conducted in‐matrix application of the same systems. Results were attributed to molecular interactions and mass transport processes that rendered lauric arginate less active when applied as emulsions or solid lipid particles. Results highlight the importance of understanding physicochemical properties when using interfacially active antimicrobials.