Use of phosphorus by cow’s breast tissue in the lactation periods during the day
Authors: Плюта Лариса 
Published: June 2020

The article examined the use of Phosphorus by cows of Phosphorus breast tissue during the day and lactation. In the new lactation period, on average, 0.14±0.028 mmol/l, or 9.46 % of the Phosphorus from the inflowing blood, was absorbed by the cows of Phosphorus breast tissue from the first to the second milking. In the period from the second (lunchtime) to the third (evening) milking, the following dynamics use of Phosphorus by cows of Phosphorus breast tissue was established. Two hours after the first milking, breast tissue absorbed 0.19±0.038 mmol/l of Phosphorus (12.92 %) from the inflowing blood. In the fourth hour after milking the use of Phosphorus by cows of Phosphorus breast tissue decreased and was to 10.52 %, or 0.16±0.032 mmol/l. Six hours after milking, breast tissue reduced Phosphorus adsorption from inflowing blood to 0.09±0.018 mmol/l and increased its use by eight hours after milking to 0.12±0.024 mmol/l. On average, from the second (afternoon) to the third (evening) milking, the cows of Phosphorus breast tissue used 8.72 % of Phosphorus from the inflowing blood. In the second and fourth hours after the third (evening) milking, the breast tissue used Phosphorus at almost the same level – 0.18±0.036 mmol/l and 0.17±0.034 mmol/l, or 12.08 % and 11.72 %. For six hours, the adsorption of Phosphorus by breast tissue decreased to 0.10±0.020 mmol/l and increased by eight hours to 0.14±0.028 mmol/l. On average, in the new lactation period from evening to the morning milking the cows of Phosphorus breast tissue adsorbed 0.13±0.026 mmol/l of Phosphorus from arterial blood, or 8.84 % of its content in arterial blood.  On average, in the period from the third evening until the morning milking during the new milking period the cows of Phosphorus breast tissue adsorbed 0.13±0.026 mmol/l of Phosphorus from arterial blood, or 8.84 % of its content in arterial blood. In the mid-lactation, the use of Phosphorus by the cows of Phosphorus breast tissue had some dynamics. Two hours after the first milking, 0.12±0.024 mmol/l of Phosphorus, or 7.74 % was absorbed by breast tissue from arterial blood. On average, from the first to the second milking, the cows of Phosphorus breast tissue absorbed 0.09±0.016 mmol/l, or 6.19 % of Phosphorus. On average, from the second (lunchtime) to the third (evening) milking the cows of Phosphorus breast tissue used 6.38 % of Phosphorus from inflowing to them blood.

It should be noted that as in the period of new milking, from the second to the third milking breast tissue adsorbed Phosphorus from the inflowing blood more intensively. Before the third (evening) milking the breast tissue absorbed 0.08±0.016 mmol/l of Phosphorus (5.09 %). Two hours after milking, this indicator increased by 1.56 times (р<0,001). Four hours after milking the cows of Phosphorus breast tissue reduced the Phosphorus adsorption significantly from the inflowing blood (0.09±0.018 mmol/l). Subsequently, in the sixth and eighth hours after the third milking the cows of Phosphorus breast tissue adsorbed Phosphorus from the inflowing blood at the level of 0.07±0.014 and 0.05±0.01 mmol/l. On average, from the time of the third to the first milking the cow&apos;s breast tissue reduced Phosphorus using by 2.80 times (р<0,001). 

In the middle of lactation, the cows of Phosphorus breast tissue adsorbed 0.092±0.018 mmol/l, or 6.03 % of Phosphorus on average, which is 1.28 times less than in the first lactation period (р<0,01). During the day, the cows of Phosphorus breast tissue reduced Phosphorus using from the inflowing blood from milking to milking by 2.41 times (р<0,001).

It was found that during the decline lactation period cows of Phosphorus breast tissue practically did not reduce the absorption of Phosphorus from the inflowing blood. On average, during the decline lactation period cow&apos;s breast tissue used 0,085±0,016 mmol/l of phosphorus from the inflowing blood. We found that 6.48 % of phosphorus from inflowing arterial blood was used by cows of Phosphorus breast tissue during lactation in providing the cows of Phosphorus organism according to the feeding norms. In general, the cows of Phosphorus breast tissue reduced the using of Phosphorus during the day in milking period by 1,21 times, 2.41 times in the middle of lactation and 1.51 times during the lactation decline while providing the cows with nutrients according to feeding norms (р<0,001). In the new milking period the using of Phosphorus by cows of Phosphorus breast tissue was 8,78  %, in the middle of lactation – 6.03 % and 5.70 % during the period of lactation decline. In the new milking period cows of Phosphorus breast tissue absorbed 8,78 % of Phosphorus from arterial blood, which is 1.45 times more than in the middle of lactation and 1.54 times more than in the period of lactation decline.