CC BY
21
УДК/ UDC 636.234.1.034.003.12
COMPARATIVE EVALUATION OF MILK PRODUCTIVITY OF HOLSTEIN COWS DIFFERENT LINES IN DIFFERENT AGE PERIODS
СРАВНИТЕЛЬНАЯ ОЦЕНКА МОЛОЧНОЙ ПРОДУКТИВНОСТИ ГОЛШТИНСКИХ КОРОВ РАЗНЫХ ЛИНИЙ В РАЗЛИЧНЫЕ ВОЗРАСТНЫЕ ПЕРИОДЫ
Lyashuk A.R., Postgraduate Student Ляшук А. Р., аспирант Federal State Budgetary Educational Establishment of Higher Education "Orel State Agrarian University named after N.V. Parakhin", Orel, Russia
ФГБОУ ВО «Орловский государственный аграрный университет имени Н.В. Парахина», Орел, Россия E-mail: [email protected]
Many have studied the influence of Holstein cows in connection to lactation, as well as their linearity on milk productivity. The study of this problem relating to the Orel region is also very relevant and has practical value. The first-calf heifers of the Reflection Sovereign line had a significantly higher milk yield and were characterized by higher milk production rates than the first-calf heifers of the Vis Back Ideal line by 6.48 and 6.06%, respectively (P<0.05). At the age of the third lactation, the Reflection Sovereign cows exceed the Vis Back Ideal cows in terms of milk yield and milk yield by 10.58 and 9.55% (P<0.05). A significant margin of indicators of the amount of milk fat and the coefficient of relative fat content of cows of the Reflection Sovereign line was revealed over the cows of the Vis Back Ideal line of the first and third lactation age. The milk of first-calf heifers of the Reflection Sovereign line contained more milk protein than the first-calf Vis Back Ideal by 6.49% (P<0.05). At the same time, the indicator of the coefficient of specific white milk production exceeded the indicator of first-calf heifers of the Vis Back Ideal line by 6.87% (P<0.05). The amount of milk protein obtained from the experimental cows of the Reflection Sovereign line in the third lactation exceeded the indicator of the Vis Back Ideal peers by 10.48% (P<0.01). A fourfold shape of the material is formed. By the second lactation, the cows of the Vis Back Ideal line exceeded the milk yield of first-calf heifers by 16.55% (P<0.001). Indicators for the third and second lactation did not have significant differences than the milk yield for the fourth lactation by 7.3% (P<0.05). The milk yield of cows of the Reflection Sovereign line in the second lactation significantly exceeded the milk yield of first-heifers by 10.95% (P<0.01), and the milk yield in the third lactation exceeded the milk yield in the second lactation by 11.09% (P<0.01).
Key words: dairy cattle breeding, milk productivity of cows, age of cows, milk yield, milk production coefficient, fat and milk content, milk protein, correlation between the characteristics of productivity.
Многие исследователи изучали различные аспекты влияния возраста коров голшгинской породы в разрезе лактаций, а также их линейной принадлежности на молочную продуктивность. Изучение данной проблемы в условиях Орловской области также весьма актуально и имеет практическое значение. Первотелки линии Рефлекшн Соверинг имели достоверно больший удой и характеризовались более высоким коэффициентом молочности, чем первотелки линии Вис Бэк Айдиал соответственно на 6,48 и 6,06% (Р<0,05). В возрасте третьей лактации коровы линии Рефлекшн Соверинг превышали показатели коров линии Вис Бэк Айдиал по удою и коэффициенту молочности на 10,58 и 9,55% (Р<0,05). Выявлено достоверное превышении показателей количества молочного жира и коэффициента жирномолочности коров линии Рефлекшн Соверинг над коровами линии Вис Бэк Айдиал возрасте первой и третьей лактации. В молоке первотелок линии Рефлекшн Соверинг содержалось больше молочного белка, чем первотелок Вис Бэк Айдиал на 6,49% (Р<0,05). При этом показатель коэффициента удельной белковомолочности превышал показатель первотелок линии Вис Бэк Айдиал на 6,87% (Р<0,05). Количество молочного белка, полученного от подопытных коров линии Рефлекшн Соверинг в третью лактацию, превышало показатель сверстниц линии Вис Бэк Айдиал на 10,48% (Р<0,01). Возрастная динамика удоя голштинских коров различных линий на протяжении последующих четырех лактаций характеризовалась поступающим увеличением показателей. По второй лактации коровы
линии Вис Бэк Айдиал превосходили удой первотелок на 16,55% (Р<0,001). Показатели по третьей и второй лактации не имели достоверных отличий, а удой по четвертой лактации был выше, чем удой по третьей лактации на 7,3% (Р<0,05). Удой коров линии Рефлекшн Соверинг по второй лактации достоверно превышал удой первотелок на 10,95% (Р<0,01), а удой по третьей лактации превышал удой по второй лактации на 11,09% (Р<0,01). Ключевые слова: молочное скотоводство, молочная продуктивность коров, возраст коров, удой, коэффициент молочности, жирномолочность, белковомолочность, корреляция между признаками продуктивности.
Introduction. The production of raw milk and basic dairy products in Russia continues to grow, following a long-term trend. The total production of raw milk in the country increased in the first half of 2020 by 3.6% to 15.8 million tons. In the commodity sector, a more pronounced increase was seen - by 6.1% as a whole (to 11.7 million tons), including in agricultural organizations - by 8% (up to 8.7 million tons) in peasant farms, and by 9% (up to 1 million tons) in individual entrepreneurs. The increase in production is due to the introduction of new complexes, an increase in the milk productivity of cows, and the level of marketability. However, the consumption of dairy products in 2020 is steadily decreasing due to the fall in purchasing power, and there is every reason to predict a decline in consumption of dairy products by 3-4% by the end of the year [1 ].
On the dairy market, the Orel region has significant unrealized potential and many competitive advantages, which include favorable natural and climatic conditions, a good level of transport and energy infrastructure, free production capacity, and qualified personnel [2].
To apprehend the production potential of the dairy subcomplex in the Orel Region, it is necessary to quickly develop and implement scientifically grounded recommendations for increasing the productivity of the dairy herd and improving the milk production technology, which will allow the region to take its rightful place in the Russian dairy market. According to a number of authors, the main reserves are in the area of increasing the productive qualities of the livestock of specialized dairy breeds, the most prominent representative of which is the Holstein breed [3-6].
It is well known that an increase in the productivity of dairy cows occurs up to 4-5 lactation. However, in recent decades, because of a change in the genotype of farm animals due to the mass introduction of the Holstein breed, as well as an increase in the intensity of the use of lactating livestock, the average duration of productive longevity of dairy cattle has decreased to 2.6 lactations and continues to decline.
In this regard, many domestic and foreign researchers in recent years have studied various aspects of the influence of the age of Holstein cows in the context of lactations, as well as their linearity on milk productivity [7-20]. Undoubtedly, the study of this problem in the conditions of the Orel region is also very important and has practical value.
Based on the above, the purpose of the work was a comparative assessment of the milk productivity of Holstein cows of different ages and linearity in the conditions of the Orel region.
Materials and methods. The studies were carried out in the period from 2019 to 2020 at the state Holstein breeding farm, Slavyanskoye, in the Verkhovsky District of the Orel Region. The farm uses loose box keeping of animals with milking cows in the milking parlor. The rations for feeding lactating cows on the farm were per zootechnical standards.
The objects of research were all cows of the main herd, divided into groups by age in terms of lactations (from 1 to 4 inclusive), as well as by linearity. The material of the research was the data of zootechnical documentation, individual cards of a breeding cow, acts of control milking and reports of milk quality assessment by mass fraction of milk fat and milk protein.
Following the tasks set for this study, the experimental part of the work was a scientific and economic experiment, the diagram of which is shown in Figure 1.
Biometric processing of the experimental results was carried out using Microsoft Excel. The arithmetic mean, the arithmetic mean error, the correlation (r), the criteria for the reliability of the difference between the groups (td) were calculated using the Lakin method [21].
Figure 1 - Experiment scheme
Research results. Following the tasks set, a comparative study of the milk productivity of Holstein cows of different ages and lineage was carried out (Table 1).
Table 1 - Milk productivity of cows, M±m
Vis Back Ideal Line (control group)
Indicators 1 lactation, n=179 2 lactation, n=118 3 lactation, n=43 4 lactation, n=11
Live weight, kg 563±0,29 583±0,44 595±0,67 604±1,42
Milk yield, kg 8083±94 9421±134 9593±252 10293±201
Coefficient of relative milk yield, % 1436±16,8 1616±23,1 1612±42,8 1705±31,8
Reflection Sovereign Line
Indicators 1 lactation, n=61 2 lactation, n=29 3 lactation, n=10 4 lactation, n=10
Live weight, kg 565±0,66* 583±0,74 601±2,36* 604±1,22
Milk yield, kg 8607±198* 9549±266 10608±268* 10783±229
Coefficient of relative milk yield, % 1523±34,5* 1638±45,2 1766±45,4* 1795±38,1
Note. * - P < 0.05; ** - P < 0.01.
The results presented in Table 1 demonstrate the established proportion of studies of the excess of milk production indicators of Reflection Sovereign cows over Vis Back Ideal cows at the age of the first and third lactation. Thus, first-calf heifers of the Reflection Sovereign line had a higher relative milk yield coefficient than first-calf heifers of the Vis Back Ideal line, respectively, by 6.48 and 6.06% (P<0.05). During the third lactation, Reflection Sovereign cows exceeded the Vis Back Ideal cows in terms of milk yield and relative milk yield coefficient by 10.58 and 9.55% (P<0.05).
Concerning the milk yield and relative milk yield coefficient of the experimental cows at the age of the second and fourth lactations, a tendency was also verified for exceeding the indicators of cows of the Reflection Sovereign line, however, the statistical significance of differences in indicators was not detected.
In general, the superiority of first-calf heifers and cows of the Reflection Sovereign line over first-calf heifers and cows of the Vis Back ideal line in terms of milk yield and milk yield in the first and third lactation has been proven.
A comparative assessment of the fat content of Holstein cows of different ages and linearity is presented in Table 2.
The data obtained concerning the fat content of Holstein cows of different ages and linearity indicate a significant excess of the indicators of the amount of milk fat and the coefficient of the fat content of the Reflection Sovereign cows over the Vis Back Ideal cows of the first and third lactation age. The established excess was, respectively, for first-calf heifers - 6.23 and
6.24% (P<0.05), and for the third lactation - 10.47 and 9.63% (P<0.05). The tendencies for the excess of the fat content of the cows of the Reflection Sovereign line over the counterparts of the Vis Back Ideal line of the second and fourth lactation were statistically insignificant.
Table 2 - Fat content in cow milk, M±m
Vis Back Ideal Line (control group)
Indicators 1 lactation, n=179 2 lactation, n=118 3 lactation, n=43 4 lactation, n=11
Mass fraction of fat (MFF),% 3,77±0,01 3,80±0,02 3,79±0,04 3,81±0,06
The amount of milk fat (AMF), kg 305±4,00 359±5,67 363±9,63 393±10,0
Coefficient of relative fat content in milk, % 53,90±0,77 61,55±0,98 60,94±1,64 64,97±1,62
Reflection Sovereign Line
Indicators 1 lactation, n=61 2 lactation, n=29 3 lactation, n=10 4 lactation, n=10
Mass fraction of fat (MFF),% 3,75±0,02 3,83±0,04 3,78±0,07 3,77±0,45
The amount of milk fat (AMF), kg 324±8,30* 368±13,4 401±14,2* 407±10,3
Coefficient of relative fat content in milk, % 57,26±1,45* 63,10±2,29 66,81±2,42* 67,31±1,68
Note. * - P < 0.05; ** - P < 0.01.
Indicators of protein-milk content of cows of different ages and lineage are presented in Table 3. As follows from the research materials, the characteristics of the productivity of the experimental livestock, established in relation to milk yield and fat content, in general, corresponded to the indicators of protein content. Thus, the milk of first-calf heifers of the Reflection Sovereign line contained 6.49% more milk protein (P<0.05). At the same time, the indicator of the coefficient of relative protein content in milk exceeded the indicator of first-calf heifers of the Vis Back Ideal line by 6.87% (P<0.05).
Table 3 - Protein and milk content, M±m
Vis Back Ideal Line (control group)
Indicators 1 lactation, n=179 2 lactation, n=118 3 lactation, n=43 4 lactation, n=11
Protein mass fraction (PMF),% 3,28±0,004 3,27±0,006 3,28±0,01 3,28±0,02
The amount of milk protein (AMP), kg 266±3,12 308±4,38 315±8,40 337±6,65
Coefficient of relative protein content in milk,% 46,88±0,61 52,86±0,75 52,87±1,43 55,87±1,05
Reflection Sovereign Line
Indicators 1 lactation, n=61 2 lactation, n=29 3 lactation, n=10 4 lactation, n=10
Protein mass fraction (PMF),% 3,29±0,006 3,27±0,01 3,28±0,02 3,30±0,01
The amount of milk protein (AMP), kg 283±6,49* 312±8,24 348±8,10** 356±7,62
Coefficient of relative protein content in milk,% 50,10±1,13* 53,55±1,40 57,87±1,37* 58,85±1,28
Note. * - P < 0.05; ** - P < 0.01.
The amount of milk protein obtained from experimental cows of the Reflection Sovereign line in the third lactation exceeded the indicator of peers of the Vis Back Ideal line by 10.48% (P<0.01). Similarly, the coefficient of specific protein-milk content in cows of the Reflection Sovereign line in the third lactation exceeded the indicator of peers of the Vis Back Ideal line by 9.46% (P<0.05). According to the indicators of the milk protein content of the experimental cows at the age of the second and fourth lactations, no significant difference has been established.
At the next stage of the research, we studied the age dynamics of the milk yield of Holstein cows of various lines (Figure 2).
It was found that the age dynamics of the milk yield of Holstein cows of various lines during the next four lactations were characterized by an incoming increase in indicators. Thus, according to the second lactation, cows of the Vis Back Ideal line exceeded the milk yield of first-calf heifers by 16.55% (P<0.001). The indicators for the third and second lactation did not have significant differences, and the milk yield for the fourth lactation was higher than that for the third lactation by 7.3% (P<0.05).
Milk yield for 305 days of lactation, kg
11000 -
10500 -
10000 -
9500 -
9000 -
8500 -
8000 -
7500 -
1
Vis Back Ideal Reflection Sovereign
Figure 2 - Age dynamics of milk yield of Holstein cows of various lines
The age dynamics of milk yield in Reflection Sovereign cows, in general, had similar features. So, the milk yield of cows in the second lactation significantly exceeded the milk yield of first heifers by 10.95% (P<0.01), and the milk yield in the third lactation exceeded the milk yield in the second lactation by 11.09% (P<0.01). Concerning milk yield for the fourth and third lactation, no significant difference has been established.
Conclusions. Based on the research conducted, the following conclusions were formulated:
1. First-calf heifers of the Reflection Sovereign line had a significantly higher milk yield and were characterized by a higher milk yield ratio than first-calf heifers of the Vis Back Ideal line, respectively by 6.48 and 6.06% (P<0.05). At the age of the third lactation, the Reflection Sovereign cows exceeded the Vis Back Ideal cows in terms of milk yield and relative milk yield coefficient by 10.58 and 9.55% (P<0.05).
2. Concerning the milk yield and relative milk yield coefficient of the experimental cows at the age of the second and fourth lactations, a tendency was also verified to exceed the indicators of cows of the Reflection Sovereign line, however, the statistical significance of the difference in indicators was not discovered.
3. There was revealed a significant excess of the indicators of the amount of milk fat and the coefficient of relative fat content of cows of the Reflection Sovereign line over the cows of the Vis Back Ideal line at the age of the first and third lactation. The established excess was, respectively, for first-calf heifers - 6.23 and 6.24% (P<0.05), and the third lactation - 10.47 and 9.63% (P<0.05).
4. The tendencies of the excess of the fat content in milk of the experimental cows of the Reflection Sovereign line over the counterparts of the Vis Back Ideal line of the second and fourth lactations were statistically insignificant.
5. The milk of first-calf heifers of Reflection Sovereign line contained more milk protein than first-calf Vis Back Ideal by 6.49% (P<0.05). At the same time, the indicator of coefficient of relative protein content exceeded the indicator of first-calf heifers of the Vis Back Ideal line by 6.87% (P<0.05).
6. The amount of milk protein obtained from the experimental cows of the Reflection Sovereign line in the third lactation exceeded the indicator of the Vis Back Ideal peers by 10.48% (P<0.01). The coefficient of relative protein content in cows of the Reflection Sovereign line in the third lactation exceeded the indicator of their peers of the Vis Back Ideal line by 9.46% (P<0.05). According to the indicators of the milk protein content of the experimental cows at the age of the second and fourth lactations, no significant difference has been established.
tation
2 lactation
3 lactation
4 lactation
7. The study found that the age dynamics of the milk yield of Holstein cows of various lines during the next four lactations were characterized by an incoming increase in indicators. By the second lactation, cows of the Vis Back Ideal line exceeded the milk yield of first-calf heifers by 16.55% (P<0.001). The indicators for the third and second lactation did not have significant differences, and the milk yield for the fourth lactation was higher than that for the third lactation by 7.3% (P<0.05). The age dynamics of milk yield in Reflection Sovereign cows, in general, had similar features. So, the milk yield of cows in the second lactation significantly exceeded the milk yield of first heifers by 10.95% (P<0.01), and the milk yield in the third lactation exceeded the milk yield in the second lactation by 11.09% (P<0.01). Concerning milk yield for the fourth and third lactation, no significant difference has been established.
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