scholarly journals Interdependence of productive properties of Holstein breed cows on biomass and use of mobile milking machines

2021 ◽  
Vol 244 ◽  
pp. 02018
Author(s):  
M. Ashirov ◽  
D. Omonov ◽  
R. Khalilov ◽  
U. Rakhimov

Studies have established that the highest monthly milk yield in cows of all groups was noted in the third month of lactation. In this month of lactation in cows of the III group with a live weight of 481 kg and more, the monthly milk yield was, respectively, 44 and 24 kg higher than in the peers of the I and II groups. The highest monthly milk yield of cows of groups I, II and III was, respectively, 12.33%, 12.37% and 12.53% of milk yield per lactation. Studies have confirmed that the level of payment for feed with dairy products is closely related to the level of milk production of cows. The cost of feed units for milk production in high-yielding cows is noticeably lower than in less productive peers. It was also found that the use of mobile mobile milking machines contributes to the complete milking and the manifestation of the potential of milk productivity of Holstein cows.

2017 ◽  
Vol 19 (74) ◽  
pp. 48-51
Author(s):  
L. V. Ferenz

The influence of bullock`s different breeding value for reproductive ability and milk production of their  daughters were investigated. Established that the age of first productive insemination of heifers Ukrainian black spotted milk breed, was 17.5–18.6 months and age of first calving – 26.6–27.8 months. Heifers` live weight at the first insemination was 361.4–407.1 kg. During first lactation the highest productivity had daughters from parents with breeding value by milk yield more than 801 kg. In the first lactation wasn’t found significant difference in duration service-period and interparturition-period for cows derived from progenitors with different breeding value. In the second lactation best indexes in duration service-period and interparturition-period for cows derived from progenitors with breeding value by milk yield 601–800 kg and more than 801 kg. In the third, the highest lactation, these indexes were best for cows derived from progenitors with breeding value by milk yield 601–800 kg. The difference in milk yield during first lactation between heifers received from progenitors with breeding value by milk yield less than 200 kg and heifers from bullock`s  with breeding value 401–600 kg was 292 kg. The difference in milk yield between heifers received from progenitors with breeding value by milk yield less than 200 kg and heifers from bullock`s  with breeding value  with breeding value 601–800 kg  was 660.3 kg. The difference in milk yield between heifers received from progenitors with breeding value by milk yield less than 200 kg and heifers from bullock`s  with breeding value more than 801 kg was  920.8 kg In the second lactation this difference was 589.8 (Р < 0.001), 841.5 (Р < 0.001) і 894.4 (Р < 0.001) kg of milk, in the third, the highest lactation – 754.5 (Р < 0.001), 951.8 (Р < 0.001) і 1335.7 кг (Р < 0.001).


Author(s):  
S.V. NIKOLAEV ◽  
N.A. SHEMURANOVA

Представлены данные о продуктивности коров холмогорской породы и их помесей с различной степенью голштинизации. В период с 2000 по 2019 год установлено, что в условиях Республики Коми коровы с долей кровности более 75 по голштинской породе превосходят чистопородный холмогорский скот по показателям молочной продуктивности и жира в молоке за 1-ю лактацию на 40,3 и 0,63 абс., а в 3-ю на 52,8 и 0,64 абс., соответственно. Однако повышение молочности за лактацию не приводит к увеличению пожизненного производства молока, что обусловлено снижением продолжительности хозяйственного использования. У коров с долей кровности по голштинам более 75 средний возраст выбытия составляет 2,400,11 отела, что в 1,5 раза меньше по сравнению с чистопородными животными.Наибольший пожизненный удой имеют животные с кровностью 50, полученные при скрещивании чистопородного голштинского и холмогорского скота (19850618 кг), а наименьший с кровностью 2550 при разведении помесей в себе (123281134 кг). Продукция молочного жира за все лактации у коров с кровностью 50 составляет 799,625,3 кг, что в 1,9 раз больше аналогичного показателя животных с долей кровности до 25. При учете молочной продуктивности на 1 день жизни животного установлено, что наибольший показатель наблюдается у коров с кровностью 50 7,4 кг молока натуральной жирности, а при пересчете на базисную жирность (3,4) у высококровных (более 75) по голштинской породе помесей (9,00,3 кг), где также наблюдается наибольший показатель производства молочного жира на 1 день жизни 307,310,1 г.The article presents data on the productivity of cows of the Kholmogorskaya breed and their crosses with varying degrees of holsteinische. In the course of studies conducted in the period from 2000 to 2019, it was found that in the Komi Republic, cows with a blood content of more than 75 of the Holstein breed outperform pure-bred Kholmogorsky cattle in terms of milk productivity and fat in milk for the first lactation by 40.3 and 0.63, and in the third by 52.8 and 0.64 respectively. However, an increase in milk yield per lactation does not lead to an increase in lifetime milk production, which is due to a decrease in the duration of economic use: in cows with a Holstein blood ratio of more than 75, the average leaving age is 2.400.11 calving, which is 1.5 times less than in purebred animals. The highest lifetime yield is given to animals with a blood content of 50 obtained by crossing Chi-pedigree Holstein and Kholmogorsky cattle (19850618 kg), and the lowest with a blood content of 2550 when breeding crossbreeds in themselves (123281134 kg). The production of milk fat during all lactation in cows with a blood content of 50 is 799.625.3 kg, which is 1.9 times more than in animals with a blood content of up to 25. When accounting for milk production on a day in the life of an animal is established that the highest milk yield observed in cows with percentage of the blood 50 and 7.4 kg of milk, natural fat content, and at recalculation on basic fat content (3.4) from 75 of the Holstein breed hybrids (9.00.3 kg), which also has the highest production of milk fat on day 1 of life 307.310.1 grams


Author(s):  
Murodulla Eshonqulovich Ashirov ◽  
Khusniddin Abdiolimovich Donaev ◽  
Alo Askarovich Yuldashev

Studies have revealed that despite the selection, the Holstein cows have a high genetic potential of milk production and in all lactations it is good in the specific conditions of the hot climate of Uzbekistan. The milk production level of German cows for the first lactation was 6511.2 kg of milk with a fat content of 3.84%, the Dutch — 6653.0 kg with fat content of 3.95%, and local breed — 6495.2 kg with a fat content of 3.95%. All mature cows retained high milk production, for III lactation and older it was 7112.5 kg and 3.90%, 7266.0 kg and 3.90%, 6847.5 kg and 3.94%, respectively. The yield of Dutch breeding cows was higher for 1 lactation by 141.80–157.8 kg, for III lactation and older by 153.5–418.5 kg, the yield of milk fat by 12.8–6.3 kg, respectively, of indicators peers of German and local selection. The cows of the studied selections combined well with high milk yield and fat content. The level of 4% milk for the studied lactation in all cows was quite high and testified to its good nutritional value. Holstein cows of different breeds are distinguished by a strong dairy type. For I lactation, for every 100 kg of live weight, 1,159.0–1265.5 kg of milk was produced, for III lactation and older - 1200.0–1308.6 kg. It is revealed that milk productivity depends on the level of live weight of cows. The increase in body weight of cows in all groups provides an increase in milk yield, milk fat yield, milk yield of 4% milk. Milk productivity is interrelated with the duration of the service period. In group I, cows with a service period of 91–100 days were more productive, in group II, 81–90 and in group III, up to 80 days. The use of Holstein cows for the production of milk is effective and ensures an increase in its production, the creation of highly productive dairy herds and the production of high-quality maintenance stock. KEYWORDS: Holstein breed, herd, milk yield, milk, fat, selection.


2016 ◽  
Vol 52 ◽  
pp. 6-12 ◽  
Author(s):  
M. V. Gladiy ◽  
G. S. Kovalenko ◽  
S. V. Priyma ◽  
G. A. Holyosa ◽  
A. V. Tuchyk ◽  
...  

The main goal of dairy breeds selection should be improving breeding and productive qualities of animals under modern conditions. The majority of farms, using native breeds to produce milk, has created optimal conditions for keeping and feeding, selection and matching, growing of replacements etc. Further improvement of created native dairy breeds for economically useful traits occurs at total use of purebred Holstein bulls (semen) of foreign selection. In order to realistically assess milk productivity (milk yield, fat content in milk and fat yield) of Ukrainian Black-and-White and Red-and-White Dairy cows should be conducted a comparative analysis of Holstein cows under the same conditions of feeding and keeping. It was established that Ukrainian Red-and-White Dairy cows were characterized by the highest milk yields for 305 days of all lactations, taken into account, the among three investigated breeds. Their milk yield during the first lactation was 5933 kg of milk, during the second – 6393 kg, the third – 6391 kg and during higher lactation – 6650 kg. Ukrainian Black-and-White Dairy cows were second by milk yield (except for the second lactation), during the first lactation – 5932 kg of milk, the third – 6462 kg and higher – 6541 kg, and Holstein cows were third, during the first lactation – 5794 kg of milk, the second – 6381 kg, the third – 6335 kg and higher – 6469 kg. The fat content was almost the same and varied within 3.49-3.58% in milk of Ukrainian Red-and-White Dairy cattle, 3.50-3.60% in milk of Ukrainian Black-and-White Dairy cattle and 3.50-3.56% in Holsteins’ milk. The difference between the breeds was within 0.01-0.04%. All the investigated breeds had predominance in fat yield for three lactations over standards of these breeds: Ukrainian Red-and-White Dairy cows from 75.1 to 93.4 kg, Ukrainian Black-and-White Dairy cows – 75.1-89.0 kg respectively and Holstein cows – 41.9-60.2 kg. It was found different level of positive correlation between milk yield and fat yield in all the cases and high correlation (r = 0.604-0.921, P < 0.001) in five cases (41.7%) Negative correlation coefficients indicate that selection of animals to higher milk yield in the herd will decrease the second trait – fat content in milk. Positive and highly significant correlation between milk yield and fat yield indicates that selection of cows in the herd to higher milk yields will increase fat yield. It was revealed that bulls were among the factors impacted the milk productivity (milk yield, fat content, fat yield) of three investigated breeds. So, the force (η²x) of father’s impact on milk yield was15.4-47.9%, fat content – 22.0-43.4% and fat yield – 14.9-47.7% taking into account a lactation and a breed. The force of lines impact (η²x) was second; it was on milk yield 6.1-24.5%, fat content – 4.1-17.1 and fat yield – 5.8-23.5%. The force of breeds impact (η²x) was last; it was on milk yield 0.3-2.9%, fat content – 0.2-0.3% and fat yield – 0.6-2.7%. So, the comparative studies of milk productivity of Ukrainian Red-and-White and Black-and-White Dairy cattle with Holsteins indicate that under similar conditions of feeding and keeping, these native breeds can compete with Holstein cattle. The milk yield for 305 days of higher lactation was 6650 kg of milk in Ukrainian Red-and-White Dairy cows, 6541 kg in Ukrainian Black-and-White Dairy cows and 6469 kg in Holsteins. It was found the inverse correlation r = -0.025-0.316 between milk yield and fat content in milk in most cases. Selection and matching of animals in the herd should be carried out simultaneously on these traits. It was found positive repeatability of milk yields between the first and second, the third and higher lactations (rs = 0.036-0.741), indicating the reliability of forecasting increase in milk productivity during the next lactations in all herd. Bulls have the greatest impact (η²x) on milk productivity among the factors taken into account: milk yield – 15.4-47.9%, fat content in milk – 22.0-43.4% and fat yield – 14.9-47.7%.


Author(s):  
A. Zheltikov ◽  
N. Kostomakhin ◽  
D. Adushinov ◽  
O. Zaiko ◽  
V. Dementev ◽  
...  

The characteristic of milk productivity of cows of Holstein and Simmental breeds in LLC “Sibirskaya Niva” in the Maslyaninsky district in the Novosibirsk region has been given. It has been revealed that under the natural and climatic environments of the Western Siberia, when creating favorable conditions for feeding and housing for cows of Holstein and Simmental breeds have sufficiently high milk productivity. It has been found that Holstein first-calf heifers surpassed their Simmental herdmates by 959 kg in milk yield for the first 305 days of lactation under the same conditions of housing and feeding, by 3,1 kg in daily milk yield, by 38,2 kg in milk fat yield, and by 28,3 kg in milk protein yield (P < 0,001). There were no statistically significant differences between animals of Holstein and Simmental breeds in terms of fat and protein content in milk, which amounted to 3,94 and 2,96 % in Holstein breed and 3,97 and 2,98 % in Simmental breed, respectively. Both breeds have shown high milk productivity during the first 3 lactations. Thus, the milk yield of Holstein cows for the first 3 lactation was 6475–9290 kg, Simmental cows it was 5516–7680 kg, fat content was 3,93–3,99 and 3,96–3,97 %, respectively. The protein content in the milk of cows of both breeds did not exceed 3,0 %. High variability has been found in milk yield, yield of milk fat and protein, the coefficient of milk content and duration of lactation, the lowest in the content of protein and fat in milk and live weight. The correlation coefficients between the fat and protein content in milk were generally positive, but did not exceed 0,28. Therefore, breeding in the herd of cows in LLC “Sibirskaya Niva” have to be conducted not only by fat content, but also by protein content in milk.


Author(s):  
N. Kosyachenko ◽  
Marina Abramova ◽  
M. Lapina

Abstract. Aim. The study of the influence of crossbriding on the growth and development of heifers and subsequent productive and reproductive qualities of cows on the first lactation. Methods. Using statistical methods, correlation analysis and ANOVA for evaluated genetic indicators of economic-valuable traits of dairy cattle. In particular was studied live weight of heifers from birth to 18 months, first insemination age and first fecundation age, live weight at fecundation, frequency of insemination, first calving age, days open, live weight at first lactation, milk yield for 305 days (kg), fat (%, kg) and protein (%, kg) in milk. Results. Relationship between productive indicators and the genotype of the animal is established. When assessing the strength of the influence of the factor «blood on the Holstein breed» it was found that the greatest impact can be traced at the age of 6 and 18 months, and is respectively 12.7 % and 17.1 %.The reproductive qualities of the first-calf cows decreased with the increase percent of blood in the Holstein breed. Evaluation of the impact of crossbreeding on milk production at first lactation has revealed significant strong influence on milk yield for 305 days of first lactation, and related signs the amount of milk fat and protein. According to qualitative indicators, the low influence of the Holstein blood fraction was found, while to a greater extent on the fat content than on the protein content in milk. Evaluation of phenotypic and genotypic correlations of milk yield and quality components of milk revealed average negative phenotypic and low negative genotypic correlation in all groups. The exception was in heifers of Yaroslavl breed with percent of Holstein blood less than 50 %, in which the relationship of yield x protein was positive. The relationship between milk yield and fat and protein content in milk has the opposite moderate character and strength. Practical significance. Studies was established that breeding of animals of Holstein and Yaroslavl breeds in one herd allows to receive an optimum ratio of milk production with optimal percentage fat and protein. For this herd among animals of the improved genotypes of the Yaroslavl breed, the use of genotypes with a percent of blood in the Holstein breed from 75.1 % to 87.6 % is optimal, which should be taken into account when selecting bulls to the breeding program.


2020 ◽  
Vol 59 ◽  
pp. 26-34
Author(s):  
S. L. Voitenko ◽  
O. V. Sydorenko

The scientific community has shown that the genetic improvement of dairy cattle depends on many genotypic factors, including paternal ancestry and lineage. With this in mind, the purpose of our research was to evaluate the Holstein bulls of black-and-white and red-and-white suits of different lines for the milk productivity of their daughters. The research was carried out on the basis of primary breeding records of 10 breeding herds of Ukrainian Black-and-White Dairy breed, 3 – Ukrainian Red-and-White Dairy breed and one – Ukrainian Red Dairy breed, which are subordinated to NAAS. Cows of the studied breeds has divided into groups according to lineage and paternal origin. Studies have revealed a significant differentiation of milk yield of cows of the first and highest lactation not only of one breed, but also of linear affiliation and paternal origin. It was found that the yield of the first lactation in cows of the Ukrainian Black-and-White Dairy breed varied from 3211 kg (Damir 7100354042) to 7884 kg (Dzhokus 113080315) of milk. Noteworthy are the daughters of Dzhokus 113080315, from which 9143 kg of milk were obtained for higher lactation, Polyarsten 342347941 and Manteno 344222859 – 8248 kg and 8290 kg of milk, respectively. The significant influence of paternal origin on the yield of Ukrainian Black-and-White Dairy breed cows of the first and higher lactation (31.0%; P > 0.999) and 37.3% has been proved; P > 0.999). The influence of genealogical formation on the milk productivity of cows was significant and amounted to 10.8% for the first lactation, higher – 10.2%. Some of the first-born Ukrainian Black-and-White Dairy breed has characterized by high milk productivity, which steadily increased until the third and higher lactation. The yield of cows of the Ukrainian Red-and-White Dairy breed of the first lactation varied from 5414 kg (Dialog 2009) to 6689 kg (Larets 6177), testifying to better homogeneity of herds in terms of milk productivity compared to the Ukrainian Black-and-White dairy breed. The highest yield of the third and highest lactation – 7626 kg, had cows-daughters of the bull Roman 660886883 Starbuck line 352790. The variability of milking cows of Ukrainian Red-and-White Dairy breed of the first and highest lactation by 25.0% and 15.2%, respectively, was due to the influence of the father offspring and to a lesser extent – belonging to the line. A very high (6517–8013 kg) realization potential of milking cows of the Ukrainian Red Dairy breed was established, but it also depended on the paternal origin and linear affiliation. The highest yield of the first lactation were shown by the daughters of the bull Belisar 365235897, Dzhorin 114414759 and Tumpi 112367468, who produced 8013 kg, 7323 kg and 7170 kg of milk, respectively. In cows of this breed it was found that yield increased with increasing serial number of lactation, with the third and higher lactation cows produced more than 8000 kg of milk per lactation, and the daughters of bull Dzhorin 114414759 – more than 9000 kg. The influence of the bull on the milk productivity of the first-born cows of the Ukrainian Red Dairy breed (16.7%; P > 0.999) is almost three times higher than this linear affiliation. Significant phenotypic variability of milk productivity of cows of different breeds of half-sisters by the father is established. The advantage of the daughters of the bull Belisar 365235897 of the Ukrainian Red Dairy breed on milking of the first lactation over the representatives of the Ukrainian Red-and-White Dairy breed was 1932 kg (p < 0.001). The difference in milk yield of the first lactation of the half-sisters by the father, the bull Konbeo 579810507 was 1007 kg (p < 0.01), and Roman 660886883 – 717 kg. Thus, a significant phenotypic variability of milk productivity of cows of different breeds of half-sisters by father was established. At the same time, regardless of the breeder, the cows of the Ukrainian Red Dairy breed were characterized by higher milk yield of the first lactation in comparison with the Ukrainian Red-and-White Dairy breed.


2020 ◽  
Vol 50 (2) ◽  
pp. 57-63
Author(s):  
L. L. Petrukhina ◽  
S. L. Belozertseva

The materials of the long-term (2008–2018) research into the reproductive function of cattle of the black-and-white breed of Baikal type in Irkutsk region are presented. The influence of the age at the first insemination and live weight on cows’ milk productivity, lifelong productivity and productive longevity was studied. The experiment was conducted on the basis of materials from the breeder-farm for breeding cattle of Baikal type on the groups of cows of different ages: up to 14–20 months and older. Cows inseminated at 16 months (7917 kg) had the best milk yield in the first lactation. The largest milk yield was obtained from inseminated cows with live weight of 401-410 kg. Milk production of these heifers was 7902 kg in the first lactation, 8792 kg – in the second and 8710 kg – in the third. It was revealed that age of cows and their live weight at the first successful insemination had a positive effect on the lifelong productivity and productive longevity of cows. Cows whose age at the first successful insemination was 15 or 16 months had a longer duration of productive use (productive life span of animals was 2561–2558 days, respectively). The highest lifelong productivity (34379–34585 kg) was obtained from the cows of this group. The economic efficiency of lifelong milk production was determined depending on the age of the first insemination. The highest lifelong milk productivity was obtained from cows, which were first inseminated at the age of 15–16 months. The largest revenue from sales of additional products was also received from the cows of this group (366,058–370,480 roubles per head). The results obtained allow to develop effective methods for increasing reproductive capacity of cattle.


2020 ◽  
Vol 16 (4, Accepted for print) ◽  
pp. 21-28
Author(s):  
Roman Mylostyvyi ◽  
Wladimir Kindratowicz Kostiuk ◽  
Aleksandr Chernenko ◽  
Olena Khmeleva ◽  
Julia Duda ◽  
...  

<b>This work investigated the percentage influence of country of origin and lineage on parameters of lifetime milk production in Holstein cows brought as heifers to Ukraine from Western Europe. The animals were kept untethered in new, modern, uninsulated steel cowsheds in a large dairy complex. Data from the Orsek dairy management system were used to evaluate randomly selected cows of different origins with complete lactation for lifetime milk, fat and protein yield. Despite significant differences in milk productivity between animals depending on their country of origin and line, the share of the influence of these factors was fairly small. Two-way analysis of variance showed that the percentage influence of the line on lifetime milk yield was 5,5%, and its influence on the yield of milk fat and protein was 6,3-7,8%. The percentage influence of the country of origin was even smaller, at 0,5–2,6% (with a greater impact on milk yield). The rather small effect of the factors studied could be due to the influence of environmental factors (feeding and living conditions), which should be investigated in further studies. </b>


2017 ◽  
Vol 54 ◽  
pp. 45-50
Author(s):  
G. D. Ilyashenko

The efficiency of the use of cattle of one or another breed is determined both by the level of milk productivity and the ability of the cattle to reproduce. At the same time, the future reproductive capacity, milk yield and duration of economic use to a large extent depends on the live weight and age when heifers insemination. The purpose of research. Study the effect of live weight and age at the first insemination on the milk productivity cows of Ukrainian red dairy breed. Methods. The research was carried out in the breeding plant of the state enterprise "Elite" of the Kirovograd state agricultural research station of NAAS on 697 cows of Ukrainian red dairy breeds, which were found during 2004–2014. Milk productivity of cows and their live weight and age at the first insemination were investigated according to the materials of the primary zootechnical and pedigree records. The degree of connection of live weight and age at the first insemination with milk productivity was estimated by correlation analysis. One-factor dispersion analysis determined the level of influence of the age of the first insemination and live weight on the productivity of cows. The calculations were made using methods of mathematical statistics using the software package "STATISTICA-6.1". Results of research. By the analysis of milk production on experimental cows, determined, that its level depends on the live weight of animals at the first insemination. Therefore, cows with live weight at the first insemination was 420–439 kg, dominated by mercy unique live weight of 380 kg in the first lactation at 244 kg (6242 vs 5998 kg), td = 1,96 for the third – 1069 kg (7465 vs 6396 kg), td = 2,37 by best lactation 498 kg (7916 vs 7418 kg), td = 2,03, significance level for all lactation (P < 0,05). To the milk fat, accordingly, the predominance was 13.2 kg (260,2 vs 247,0 kg), 22,9 (309,5 vs 286,6 kg) and 21,0 kg (325,1 vs 304,1 kg), the difference is close to the true values. The peers with a live weight of 400–419 kg and 440 kg and more also yielded in the first milk yield. The difference the milk I, III and the best lactation was 72 kg, 219 kg and 91 161 kg, 674, 589 kg for milk fat yield 5 kg, 10.3, 6.1 kg and 11.5 kg, 28.8, 19.5 kg, respectively. Due to the lesser number of animals, the vast majority of values did not reach a reliable level. Studies of milk productivity of cows, depending on the age of the first insemination, showed that its cow was the highest, which were counted at the age of 455 days. The lowest rates of dairy productivity were the animals that were fertilized at the age of 606 or more days. Correlation analysis found the highly reliable of feedback age insemination of cows milk yield in the first three lactation (-0,25 ... -0,37). Similar patterns of feedback for somewhat lower correlation coefficients are noted with the release of milk fat (-0,23 ... -0,33). Coherence of live weight at the I insemination and follow-on milk production was significantly lower (compared with age insemination) in absolute value, for only a certain level of first lactation milk yield and milk fat yield (P < 0,05). The significant influence of the investigated factors on milk yield of cows is established. Thus, by milk yield and milk fat and protein for 305 days of lactation cows power of influence age of first insemination exceeded 50%, the fat and protein in milk index of potency is 32 and 30% by high-confidence values for milk yield and yield of milk protein and fat . Somewhat lower than 20 to 33%, the effect of live weight on the first insemination was shown on the performance of cows. Сonclusion. The heifers of the Ukrainian Red dairy breed in conditions of the Central region of Ukraine advisable to fertilize at the age of 455 days, or 14,5–15 months, when they reach the living weight of 420–439 kg. The revealed feedback of the inseminative age and milk productivity can be explained by more intensive growth, better development and economic rapidity of the previously diced heifers and its should lead to intensive rearing of young animals. Determined, that the force of age-old influence of the first insemination on the lactic productivity of the cows exceeds 50%, the live weight reaches from 20 to 33%. Discovered tendency also confirms the expediency of intensive growth of repair heifers.


Sign in / Sign up

Export Citation Format

Share Document