The dependence of the productive qualities of pigs on the ventilation system of the premises during the suckling period of their cultivation

The dependence of the growth rate, the safety of young pigs in growing and fattening and their feeding qualities on the ventilation system of negative and uniform pressure in the suckling period of their cultivation was studied. We have found that the growth rate of piglets, and their payment of feed by growth during rearing, did not depend on the design features of the room ventilation system during suckling period. We have established some better preservation of piglets in growing with an unchanged ventilation system in the suckling and growing periods. It was revealed the tendency to insignificantly improve of the growth rate and feed payment by growths in piglets, which were grown during ventilation with uniform pressure in the suckling period. It was found that pigs that were raised during the suckling period with a uniform pressure ventilation system reached a mass of 100 kg at the age of 158.4 days, while their counterparts that were raised at that time with a negative pressure ventilation system reached the age of 159.8, that is later on 1, 4 days, or 0.88%. It wasn’t found a significant dependence of the feeding qualities of pigs on the ventilation system of the premises during the suckling period of their cultivation. There was a tendency to a slight improvement in the safety index by 1.9% in animals that were kept in the suckling period with a uniform pressure ventilation system, compared with analogues that were raised during this period with negative pressure ventilation. According to the calculation of the index of feeding qualities according to the formula M.D. Berezovsky, a comprehensive indicator of feeding qualities in animals that were raised during the suction period with uniform pressure ventilation was 21.4% higher compared to peers that were kept during negative pressure ventilation. In general, the growth rate of pigs during rearing and fattening, their safety during these periods and fattening qualities did not significantly depend on the ventilation system of the premises during the suction period of their rearing. Key words: ventilation, microclimate, sow, pig, multiplicity, growth, safety.

The Influence of the Self-Contained Breathing Apparatus (SCBA) on Ventilatory Function and Maximal Exercise

Our previous work showed that breathing low density gases during exercise with the self-contained breathing apparatus (SCBA) improves maximal ventilation (VE) and maximal oxygen consumption [Formula: see text] This suggests that the SCBA limits exercise by adding a resistive load to breathing. In this study we compared [Formula: see text] with and without the various components comprising the SCBA to determine their impact on [Formula: see text] Twelve males performed 4 randomly ordered incremental exercise tests to exhaustion on a treadmill: (1) low-resistance breathing valve only (CON); (2) full SCBA (SCBA); (3) SCBA regulator only (REG); and (4) carrying the cylinder and harness assembly but breathing through a low-resistance breathing valve (PACK). Compared to CON, [Formula: see text] was reduced to a similar extent in the SCBA and REG trials (14.9% and 13.1%, respectively). The PACK condition also reduced [Formula: see text] but to a lesser extent (4.8 ± 5.3%). At [Formula: see text][Formula: see text] was decreased and expiratory mouth pressure and external breathing resistance (BR) were increased in both the SCBA and REG trials. There was a significant correlation between the change in maximal [Formula: see text] and [Formula: see text] with the SCBA. The results show that the SCBA reduces [Formula: see text] by limiting [Formula: see text] secondary to the increased BR of the SCBA regulator. Key words: ventilation, breathing resistance, expiratory flow limitation, [Formula: see text]

Contribution of Acid-Base Changes to Control of Breathing During Exercise

The mechanisms mediating the exercise hyperpnea remain controversial; there is no unequivocal evidence that any of numerous proposed mechanisms mediates the hyperpnea. However, a great deal has been learned including the potential role of changes in PCO2, [H+], strong ion differences (SID), weak acids, or any other acid-base component. The contribution of acid-base changes to the hyperpnea during exercise is likely through known or postulated chemoreceptors. Two of these, pulmonary and intracranial chemoreceptors, do not appear critical for the ventilatory adjustments to meet the metabolic demands of exercise. A third, the carotid chemoreceptors, appear to fine-tune alveolar ventilation during exercise to minimize disruptions in arterial blood gases. The role of the fourth chemoreceptors, those within skeletal muscles, is least clear. However, there is evidence that they do contribute to the hyperpnea, and it is quite clear that a muscle chemoreflex contributes to the exercise muscle pressor reflex; thus the contribution of these chemoreceptors to the exercise hyperpnea requires additional study. Key words: ventilation, hydrogen ion, PaCO2, PO2