An experiment was carried out on weaner pigs (initial BW 10.8 kg) to estimate the maintenance requirement for lysine (Lys) and its marginal efficiency of utilisation using a comparative slaughter technique. Three groups of six pigs each were fed purified diets for 21 days supplying Lys at 19.5, 78 or 195 mg/kg W0.75, which corresponded to 50, 200 or 500% of the assumed maintenance requirement. All other essential amino acids were given at 50% excess. At the end of the experiment, pigs were killed for whole-body nitrogen (N) and amino acid analysis. A representative group of six pigs was analysed at the beginning of the experiment. Based on regression equations, relating Lys or N retention to Lys intake, Lys requirement for zero Lys retention was estimated to be 121 mg/kg W0.75, while Lys requirement corresponding to zero N retention was 41.7 mg/kg W0.75. At N equilibrium, the pigs lost 65 mg of Lys per kg W0.75 daily while at zero Lys retention, the daily N retention was 156 mg/kg W0.75 . The marginal efficiency of lysine utilisation was 0.91. It is concluded that zero lysine retention is a better criterion of lysine maintenance requirement than zero N retention.
The aim of this study was to analyse the effect of supplementary feeding of DHA (Docosahexaenoic Acid) rich algae product (Algae S TM Alltech Inc.) on production of milk, fat and protein as well as on reproduction of high yielding Holstein dairy herd. Field trial was set up on Top 10 dairy farm in western part of Slovakia, under commercial conditions. The data of high yielding dairy cows, separated in two groups of 30 (control) and 29 (trial) animals, were recorded for period of 3 subsequent months from October to December 2015. Animals were fed once a day Total Mixed Ration based diet with different feed mixture composition in trial group (+100 g Algae S TM Alltech Inc. per cow and day). Performance data were collected in accordance with official milk recording system of Breeding Services of Slovak Republic s. e. and milk samples were collected once per month according to the A4 standard methodology. The control group showed higher level of milk production compared to trial. Our study indicated that the feeding of algae caused milk fat depression and generally lower protein content in milk. Significant impact of algae feeding was found also for the level of urea in milk. In addition, the supplementary feeding of DHA may represent effective strategy to increase the percentage of pregnancies per inseminations in lactating dairy cows.
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