Number of consumers and days of display necessary for the assessment of meat colour acceptability

Visual assessment is regarded as the gold standard to evaluate meat colour shelf-life, but it is costly and time consuming. To address this issue, this paper aims to evaluate the number of consumers and days of display that are necessaries in order to assess the colour shelf-life of meat, presented with different methods, all using images. Photographs of thirty-six lamb steaks were taken just after cutting (day 0) and on each of the following days until the 14th day of display under standardized conditions. Images were presented in three different manners: 1) with days of display and animals in random order (Random); 2) days of display in sequential and animals in random order (Sequential); and, 3) days of display and animals in sequential order (Animal); they were presented to 211 consumers who evaluated visual acceptability on a 9-point scale. At day zero, visual acceptability scores were the highest in Animal, followed by Sequential, and then by the Random (P <.05) method. Scores decreased over time for all methods tested (P <.05). The Random method presented the highest standard deviation; however, an increase in standard deviation among consumers along days of display was observed for all methods tested (P <.05). Shelf-life determined by regression varied according to the method of presentation (7.83, 7.00 and 7.54 days for Random, Sequential and Animal, respectively). A minimum number of 4 day points before and 4 day points after neutral scores had been reached (scores = 5.0) were necessary in order to obtain a robust model. The minimum number of required consumers (a = 0.05; d = 0.1 and ß = 0.2 or 0.1) varied according to methodology: it was 81 to 109 consumers for Random, 69 to 92 for Sequential, and 55 to 74 for Animal. Our study indicates that an optimal number of days and evaluators can be calculated depending on the manner of sample presentation. These findings should be taken into account in further studies that aim to balance data reliability with the cost involved in meat colour analyses

Effect of feeding starter containing butyrate salt on pre- and post-weaning performance of early or normally weaned calves

Two experiments were conducted to examine the influence of the starter supplemented with butyrate salts on the performance of Holstein calves. Twenty-three and thirty-five male calves were used in the Experiment I and II, respectively. Total duration of the experiments are 70 d (35 d pre-weaning and 35 d post-weaning) and 100 d (60 d pre-weaning and 40 d post-weaning), respectively. In both of the experiments, all calves were kept together with their dam and fed colostrum for the first 3 days after calving and then housed in calf hutches. Calves were fed individually whole milk (4 l/d) with two meals and starter diets ad libutum in pre-weaning period, while total mixed ration contained starter (60%) and alfalfa hay ground (40%) were used in post-weaning period. The starter diets contained 0 (without butyrate salt, CON), 1.5 g/kg sodium butyrate (NaB15), and 3.0 g/kg sodium butyrate (NaB30) in the experiment I, 0 (without butyrate salt, CON), 2.5 g/kg calcium butyrate (CaB25) and 5.0 g/kg calcium butyrate (CaB50) in the experiment II. Live weight, live weight gain and feed intake of calves were determined weekly in each experiment. Feeding starter containing NaB increased significantly (P< 0.05) live weight, live weight gain, and feed conversion efficiency of calves during pre-weaning period, but did not postweaning period. On the other hand, feeding starter supplemented with CaB did not affect performance of calves in both periods. The present results suggest that the inclusion of NaB in starter feeds could be recommended for calves in early weaning program