No abstract

If gastric acidity is to be encouraged, it may be beneficial to eliminate some feed elements from pig starter meals since they bind more acid in the stomach than others. The cereals (wheat, maize, and barley), soybean meal, commercial mineral supplement, and two feed mixtures (one of them with the additive Zeolit) were evaluated. In this study, it was discovered that adding zeolite to the feed mixture had the effect of lowering its initial pH (P<0.001), buffering (P<0.05) and binding capacity (P<0.05). This study aimed to measure the buffering and acid-binding capacity of some ingredients commonly used in growing pig feeds and estimate the coefficient of correlation between crude protein, ash, and the buffering capacity of feed ingredients with significant linear correlation (P<0.05 and P<0.01, respectively). The combined impact of the individual feed mixture components' individual buffering capacities has not been proven.

This study was conducted to determine the effects of a low-protein diet supplemented with synthetic amino acids on the biochemical parameters in the blood serum, the indicators of fermentation processes, and nitrogen excretion in 12 crossbred piglets. The piglets (weaned at 28 days of age) were divided into two groups with 6 piglets each. The control group had an initial average body weight of 8.8 ± 0.6 kg and the experimental group with an average initial body weight of 8.6 ± 0.7 kg. The control diet contained 210.8 g.kg−1 crude protein and the experimental diet contained 186.4 g.kg−1. The experimental diet was supplemented with lysine, methionine and threonine to achieve a more ideal amino acid pattern. The blood collections from the sinus ophthalmicus for the determination of the biochemical parameters were performed 4 times at weekly intervals in the control and experimental groups 4—5 hours after feeding. The faeces were taken from the rectum at the end of the study period. The decrease in the dietary crude protein content of the experimental group was manifested by a significant decrease of the blood urea level (2.61 mmol.l−1 average concentration) compared to the control groups (4.21 mmol.l−1 average concentration) (P < 0.001). The other serum component concentrations (total protein, albumin, glucose, cholesterol, total lipids and selected enzymes) showed no significant statistical changes between the control and experimental groups. The results of the fermentation process analysis indicated that the butyrate concentration decreased (P = 0.0017) and the pH increased (P = 0.0180) in the experimental group compared to the control group. The levels of crude protein and ammonia in the faeces of experimental animals were significantly lower (P < 0.001) in comparison with those in the control animals.

The aim of this study was to evaluate the milk urea content along with the dynamics of lactation and milk components in production dependency in Holstein dairy cows. Evaluation of daily milk yield in relation to milk urea presented a positive regression dependency, which was the strongest in early lactation (r = 0.860; P < 0.001), decreasing in mid lactation (r = 0.329; P < 0.001) and late lactation (r = 0.261; P < 0.001). Evaluation of milk protein in relation to milk urea showed a negative regression dependency, which was the strongest in early lactation (r = -0.850; P < 0.001), decreasing in mid lactation (r = -0.819; P < 0.001) and late lactation (r = -0.679; P < 0.001). The somatic cell counts in relation to milk urea confirmed a negative regression dependency in early lactation (r = -0.635; P < 0.05) and mid lactation (r = -0.818; P < 0.05), but no significance was found in late lactation. The results of the study confirm the influence of production factors (milk quantity and milk components) on the milk urea content. Dependencies found between the production, milk components and milk urea are applicable for the evaluation of protein nutrition and metabolic transformation of nutrients in dairy cows.

The aim of this study was to evaluate the relationship between nutrition, the concentration of milk urea nitrogen (MUN) and the urinary nitrogen excretion in farm conditions and to use the MUN concentration as a tool to control protein nutrition and environmental load in dairy farming. Urinary N excretion was evaluated by an empirical model according to the intake and metabolic transformation of N to milk protein in selected farms was on average 208.8 ± 34.8 g with a range of values from 127.7 to 277.8 g N.day−1. The evaluated proportion of excreted N in relation to crude protein (CP) intake in the total mix ration (TMR) was statistically significant (R2 = 0.504; P < 0.0001). Urinary N excretion, evaluated according to the analysis of the MUN content, using selected regression equations, was on average 211.8 ± 24.3 g.day−1 with an individual variation of 157.2‒274.7 g.day−1 with a significantly higher positive correlation to the received CP in the TMR (R2 = 0.693; P < 0.0001). The evaluated effect of CP concentration in the TMR on urine N excretion confirmed the higher nitrogen excretion in the urine by 25.6 g per day with an increased CP in the TMR by 1 %. The proportion of urea nitrogen in the total N excreted in the urine was on average 80.5 %. The validation of the models for the prediction of nitrogen excretion, according to the MUN for the practical application on farms, was determined the best equation by Kaufmann a St-Pierre, which used available data from routine analysis of milk composition by the Breeding service of Slovakia. The MUN analysis offered a simple and non-invasive approach to the evaluation of the urinary N excretion, as well as, the efficiency of N utilization from feed to milk.