Economic and useful traits of cows of different ages

2021 ◽  
pp. 19-29
Author(s):  
O. V. Gorelik ◽  
S. Yu. Kharlap ◽  
A. S. Gorelik ◽  
A. Yu. Martynova
Keyword(s):  
Milk Yield ◽  
Positive Trend ◽  
Optimal Conditions ◽  
Physiological Maturity ◽  
The Third ◽  
Reproductive Ability ◽  
Genetic Potential ◽  
Short Period ◽  
Intensive Use ◽  
Productive Traits

Intensive use of highly productive animals has revealed new problems associated with reducing the duration of productive use of animals and reducing their reproductive abilities, which lead to a decrease in the number of young animals for rearing and fattening for beef. Therefore, the study of the infl uence of age on the productive traits of cows is relevant and has practical signifi cance. The purpose of the work was to evaluate cows for economically useful traits depending on the age of the animals. It has been found that the milk yield for lactation increases with age in cows. If from fi rst-calf heifers has been received 5163,8±212,3 kg of milk, then 6106,5±201,7 and 6846,8±231,7 from cows of the third and fourth lactation, respectively, this was more by 942,7 kg or 18,2 % and 1683,8 kg or 32,6 %. Milk yield increases gradually from lactation to lactation with increasing age of cows and thus confi rms the association of improving the productive traits of animals with the laws of development, i.e. the onset of their physiological maturity. It has been revealed that the farm does not have optimal conditions for the full manifestation of the genetic potential of productivity, and therefore cows of the third and fourth lactation have lower milk yields than possible. So, the estimated milk yield of fi rstcalf heifers to mature cows practically corresponds to the milk yield that was received from cows after IV lactation. The diff erence between groups of cows in the content of individual components of milk was insignifi cant, although there is a positive trend to reduce the content of protein and casein with increasing age of cows. Cows bred on the farm have high indicators of reproductive ability. So, they have a short period of open day from 26,6±0,61 days (II lactation) to 43,7±1,11 days (III lactation), the optimal pregnancy period and calving interval (less than a calendar year). The level of profi tability of milk production increases with increasing milk yields, which increase with age.

scholarly journals Reproductive ability and milk productivity of cows depending on breeding value of their progenitors

2017 ◽  
Vol 19 (74) ◽  
pp. 48-51
Author(s):  
L. V. Ferenz
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Live Weight ◽  
Breeding Value ◽  
Milk Productivity ◽  
The Third ◽  
Reproductive Ability ◽  
Service Period ◽  
Significant Difference ◽  
The Difference

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).

scholarly journals The Productivity of the Holstein Cows in the Process of Adaptation to the Conditions of the Iindustrial Complex of the Yaroslavl Region

2020 ◽  
Author(s):  
О.В. Филинская ◽  
М.Ю. Лапина ◽  
С.В. Зырянова
Keyword(s):  
Milk Yield ◽  
Fat Content ◽  
Dry Period ◽  
Milk Productivity ◽  
Mothers And Daughters ◽  
The Third ◽  
Reproductive Ability ◽  
Service Period ◽  
Industrial Complexes ◽  
Selection Of

Исследования проводились на одном из промышленных комплексов Ярославской области. Целью исследований являлась оценка по основным признакам продуктивности импортного скота голштинской породы селекции Нидерландов и их дочерей. Было установлено, что как матери, так и дочери имели удлинённую лактацию. Коровы импортной селекции имели высокую молочную продуктивность с первой лактации, которая составила 5597 кг с МДЖ и МДБ 4,23 и 3,38% соответственно, к третьей лактации удои увеличились до 6611,8 кг, МДЖ составила 4,35%, МДБ – 3,37%. Дочери достоверно превосходили своих матерей по продуктивным признакам, за исключением содержания белка по первой лактации, жира и белка – по третьей лактации. На комплексе и матери, и дочери имели удовлетворительную воспроизводительную способность. Выше принятых норм были продолжительность сервис-периода, сухостойного периода, возраст первого осеменения. При этом у дочерей сервис-период был меньше на 60,3 дня. Увеличение удоя является положительным показателем адаптации, с другой стороны, удовлетворительные показатели воспроизводства указывают на трудности адаптации импортного скота. Реализация продуктивных признаков имеет важное значение при ведении селекционной работы со стадом. При определении корреляции дочерей с матерями и генетического влияния наследуемости признаков от матерей была установлена корреляция по первой и третьей лактациям, соответственно: по удою – слабая отрицательная и слабая положительная, по содержанию жира в молоке – невысокая положительная, слабая отрицательная, по содержанию белка – положительная и отрицательная; наследуемость удоя, МДЖ и МДБ составила 45,1–48,3%, по третьей лактации наследуемость содержания жира от матерей – всего 12,4%. Основными причинами выбытия как матерей, так и дочерей послужили проблемы с воспроизводством, болезни конечностей и вымени. Меньше всего коровы выбывали из-за низкой продуктивности. Средний возраст использования матерей составил 1,6 лактации, у дочерей – 1,8. The researches were carried out at one of the industrial complexes of the Yaroslavl region. The aim of the research was to evaluate of imported Holstein cattle of the selection of the Netherlands and their daughters by the main characteristics of the productivity. It was found that both mothers and daughters had elongated lactation. Cows of imported selection had high milk productivity from the first lactation which was 5597 kg with WCF and WCP 4.23 and 3.38% respectively, by the third lactation milk yield increased to 6611.8 kg, WCF was 4.35%, WCP – 3.37%. The daughters were significantly superior to their mothers in productive features, with the exception of protein for the first lactation, fat and protein for the third lactation. In the complex both mothers and daughters had satisfactory reproductive ability. The duration of the service period, the dry period and the age of the first insemination were higher than the accepted norms. At the same time the service period for the daughters was 60.3 days less. The increase in milk yield is a positive indicator of adaptation on the other hand satisfactory reproduction rates indicate difficulties in adapting imported livestock. The realization of productive characteristics is important when conducting breeding work with a herd. When determining the correlation of daughters with mothers and the genetic influence of the heritability of signs from mothers, a correlation was established for the first and third lactations, respectively: by the milk yield – meanly negative and meanly positive, by fat content in milk – low positive, meanly negative, for protein content – positive and negative; the heritability of milk yield, WCF and WCP were 45.1–48.3%, according to the third lactation the heritability of fat content from mothers was only 12.4%. The main reasons for cow disposal of both mothers and daughters were problems with reproduction, diseases of the limbs and udders. Least of all cows were culled due to low productivity. The average age of use of mothers was 1.6 lactation, for daughters – 1.8.

Realization of the potential of cows of Holstein breed of different generations in terms of productive traits

2021 ◽  
pp. 28-35
Author(s):  
O. V. Nazarchenko ◽  
A. N. Rusanov
Keyword(s):  
Milk Yield ◽  
Mass Fraction ◽  
First Generation ◽  
Live Weight ◽  
High Productivity ◽  
Black And White ◽  
Holstein Breed ◽  
Genetic Potential ◽  
White Breed ◽  
Productive Traits

Breeding work with dairy cattle in the Kurgan region is aimed at breeding animals that combine the adaptive properties and valuable traits of cattle of Black-and-White breed with a high proportion of genes of Holstein breed. Such animals are characterized by high productivity and suitability for intensive technology of their housing. The purpose of the research was to determine the indicators of milk productivity of first-calf heifers of different generations of Holstein breed, imported to the pedigree farms of the Kurgan region, as well as to determine the degree of realization of the genetic potential of animals. Scientific research has been carried out in the herd of CJSC “Glinka” (Kurgan), where highly productive cattle of Black-and-White and Holstein breeds are bred. The subject of research was the first-calf heifers of the imported Holstein breed of German selection of different generations, as well as the herdmates of Black-and-White breed. It has been found that the realization of the genetic potential for milk yield in Holstein cows of German breeding was higher and amounted to 76,4 %, in cows of Black-and-White breed 69,9 %. The highest milk yield for 305 days of lactation has been observed in the second generation of Holstein heifers 8905 kg, which exceeded the milk yield of herdmates of the second and third generations by 113 kg or 1,26 % and 174 kg or 1,95 %, respectively. The mass fraction of fat in German Holsteins of different generations ranged from 3,99 to 4,21 % (P < 0,001), while the mass fraction of protein in the milk of first-calf heifers varied slightly in the range from 3,18 to 3,20 %. In terms of live weight, the animals of the third generation slightly exceeded the herdmates of the 1st and 2nd generations by 19 kg or 3,25 % and 20 kg or 3,43 %, respectively. The largest profit has been received from the first-generation first-calf heifers of Holstein breed of German selection, where the level of profitability of milk production was 50,7 %, which was higher than that of the herdmates of the second and third generations by 3,9 and 7,9 %, respectively.

The relationship between milk productivity and reproduction in cows in highly productive Ayrshire herds

2021 ◽  
pp. 40-45
Author(s):  
A. Bolgov ◽  
S. Shterkel ◽  
N. Grishina
Keyword(s):  
Milk Yield ◽  
Milk Fat ◽  
Animal Health ◽  
Correlation Coefficients ◽  
Operating Conditions ◽  
Milk Productivity ◽  
Reproductive Ability ◽  
Service Period ◽  
Short Period ◽  
The Relationship

The purpose of the study is to study the relationship between the rates of dairy productivity and reproduction of cows in the highly productive Ayrshire herds of the Republic of Karelia.Materials and methods. The work was performed on the basis of the four Stud of the Airshire rock at the "Megrega" trivial, "Ilyinskoe", Mayak LLC, Agrocomplex OJSC. V. M. Zaitseva "(Republic of Karelia). Data on dairy productivity and reproductive ability are collected and processed in 24,720 cows. Materials of zootechnical accounting and bonitations for 2004-2020 were used. At the end of the observation period, the productivity of the Stud was 7500-8500 kg of milk.From indicators of the productivity of cows, the amount of fishing, fat products for full lactation and 305 days of lactation, from the reproduction indicators - the duration of the service period, a dry period, an interstitial period (MOP), the age of the first calf, the age of cows during the selection, the causes of the selection are taken.The main biometric constants (X ̅, ϭ, CV) were calculated, the grouping method was used to characterize the signs of signs calculated the correlation coefficients.Results. The relationship between milk productivity and reproduction was studied in 4 Ayrshire herds of 24,720 cows with an average productivity of 7500-8500 kg of milk. A high positive relationship of milk yield and milk fat production with the duration of the service period (SP) was established, the correlation coefficient was up to 0.929 (P<0.001), which is consistent with the data of other researchers of this problem. It is shown that in herds with a milk yield of 8500-9000 kg of milk, the SP duration of 135-140 days is justified. It was noted that the decrease in the age of the first calving of cows led to an increase in the milk yield of the entire herd (r =-0.676; -0.686; P<0.05).A relatively short period of use of cows in herds was recorded – 3.5-3.7 lactations, while the milk yield of cows aged six lactations and older significantly exceeded the average milk yield for the herd. This leads to a positive correlation of the period of use of cows (r =0.935; P<0.001) and the proportion of cows with six lactation and older (r =0.788; P<0.05) with the milk yield of the herd. Cows with six lactations and older can stay in the herd, provided that their performance exceeds the average level of the herd. The influence of milk yield on the length of the service period and the MOP is manifested not only within one lactation, but also in adjacent lactation. It was found that with an increase in milk yield from less than 6000 kg of milk to 9500-10000 kg or more in the previous lactation, the duration of SP in the subsequent lactation increased from 112 to 170 days, MOP – from 391 to 436 (correlation coefficients from 0.138 (P<0.01) to 0.870 (P<0.001).Conclusion. The results obtained indicate the need to develop operating conditions for cows that provide a combination of high and record milk yield with normal reproductive abilities. In particular, to ensure maximum optimization of feeding conditions, maintenance, breeding and veterinary services, and control of animal health.

The state of the beef cattle industry in the Kurgan region

2020 ◽  
pp. 30-36
Author(s):  
E. Alekseeva ◽  
T. Leshchuk
Keyword(s):  
Beef Cattle ◽  
Low Cost ◽  
Live Weight ◽  
The State ◽  
Positive Trend ◽  
Industrial Complex ◽  
Department Of Agriculture ◽  
Cattle Industry ◽  
Reproductive Ability ◽  
Productive Traits

The agro-industrial complex of the country faces a strategically important task, which as to increase the production of meat, including beef. This problem has been trying to solve by creating a specialized beef cattle industry. The impetus for the development of beef cattle in the Kurgan region was the departmental target program of the Department of agriculture and processing industry of the Kurgan region “Development of beef cattle for 2011–2015”. Implementation of the Program has allowed to increase the number of beef cattle from 2010 to 2015 from 2089 to 6531 heads including cows from 666 up to 2898 heads. In subsequent years there was also a positive trend. For the development of the beef cattle industry in the Kurgan region at present there are all conditions: natural forage lands, the possibility of using low-cost intensive grazing technology, resources of breeding stock in dairy herds for the formation of new beef farms, forage grain. The results of the analysis of the state and prospects of development of this industry in the Kurgan region have been presented in the article. A positive trend has been revealed. In order to preserve the positive trends in the development of beef cattle industry of the Kurgan region it is planned to continue the annual increase of livestock, improvement of productive traits, including live weight, milk capacity and reproductive ability of cows, and improved forage base and optimization of feeding rations according to sex and age of groups.

scholarly journals LONGEVITY AND REPRODUCTIVE ABILITY OF ANIMALS OF GREY UKRAINIAN AND WHITEHEADED UKRAINIAN BREEDS

2018 ◽  
Vol 56 ◽  
pp. 162-173 ◽  
Author(s):  
N. L. Rieznykova ◽  
Yu. P. Polupan ◽  
O. V. Denysyuk ◽  
Yu. V. Vdovychenko ◽  
A. V. Pysarenko ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Population Data ◽  
Health State ◽  
Database Analysis ◽  
Equal Distribution ◽  
Still Birth ◽  
The Third ◽  
Reproductive Ability ◽  
Still Births ◽  
Intensive Use

On the materials of primary zootechnical recording in the herds of Grey Ukrainian (SE EF “Polyvanivka” of the Institute of Сereal Сrops of NAAS, 105 culled and 263 alive animals, and SE EF “Askania-Nova” of M.F.Ivanov Institute of Animal Breeding of Steppe Regions, 70 culled animals), and in the herd of Whiteheaded Ukrainian (“Podilskiy Gospodar” Ltd., 346 culled and 22 alive animals) one investigated longevity and reproductive ability of two cattle autochthonous breeds of Ukraine. Analysis of Whiteheaded Ukrainian cows’ culling data on 2013 (22 animals) testifies the designing of work on production increasing in herd, rather not high (20,5%) repair intensity (owing to lasting use of full-aged cows) and main herd animals’ successful health state. Besides it, main herd animals’ database analysis testifies long-living cows availability with their satisfactory reproductive ability at the age of 10–15 years old. To have higher conclusions’ reliability on population data one did longevity and reproductive ability data analysis of culled 346 Whiteheaded Ukrainian cows, which were born during 1978–1995. Analysis of productive longevity of investigated cows testified, that in the herd cows with the productive longevity in 1–5 lactations dominated (74,6%). Only 25 cows (7,2%) had 1 calving. The largest number of cows (70 animals) in the herd had 4 calvings. Because of twins (5,2% of the whole sample), the largest number of calves in a litter of one animal was 14 heads with equal distribution on sex. One calf for the whole lifetime had only 19 (5,5%) animals, while by 5–14 calves for the life were obtained from almost 40% of sample (138 heads). Unfortunately, in the herd there were cases of still-birth or abortions in litter of some animals. Such sad occasions comprise almost 15% of analysed sample. Investigation of genealogical affiliation of such cases revealed a bit higher number of abortions (2 out of 15 sample cases) and still-births (5 out of 45 in the sample) in the litter of bull Chas 59. But, one should take into account more intensive use of this bull at the cows of the herd. However, one should admit, that the majority (75%) of used in the herd bulls had no still-birth or abortion with different matches. Particularly, Okun 217 bull, though was used rather widely in the herd, had no still-births or abortions in the litter of its matches. Database analysis of culled cows of SE EF «Polyvanivka» testified, that out of 105 cows, 19 (18,1%) for lifetime had 10 and more (to 13) calves, 60 (57%) – 5–9 calves. Abortions and stillbirths were found only in young animals’ litter. Particularly, 10 heifers (9,5%) had stillbirths, and cows of the second calvings – 2 abortions. Amongst the animals of the third and elder calvings there were found no abortions and stillbirths. Amongst included into investigation cows of Grey Ukrainian breed of breeding plant «Markeevo» more, than half (64,3%) had 5 and more calvings. Cows with productive longevity 7–14 calvings makes up 52,9% of all investigated cows of the plant. All herd cows are characterized with easy (not lower 5,0 on beef cattle estimation scale) calvings. Comparative analysis of longevity of investigated authohtonous and Holstein or created at its base commercial breeds at the base of unpublished own research on breeding plant “Bortnychi” data and literature data reveals noticeably longer productive longevity of Whiteheaded Ukrainian and Grey Ukrainian cattle. Our investigations in the herds of Grey Ukrainian of breeding plant «Markeevo» showed, that average number of lifetime calvings was 6,45, of breeding plant «Polyvanivka» – 6,50, in the herd of Whiteheaded Ukrainian of «Podilskiy Gospodar» Ltd. – 4,49, that significantly exceeds the longevity of modern commercial breeds.

COMPARATIVE DESCRIPTION OF MILK PRODUCTIVITY OF COWS UKRAINIAN RED-AND-WHITE DAIRY CATTLE AND UKRAINIAN BLACK-AND-WHITE DAIRY CATTLE AND HOLSTEIN BREEDS IN SERF «OLEKSANDRIVSKE»

2016 ◽  
Vol 52 ◽  
pp. 6-12 ◽  
Author(s):  
M. V. Gladiy ◽  
G. S. Kovalenko ◽  
S. V. Priyma ◽  
G. A. Holyosa ◽  
A. V. Tuchyk ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Dairy Cows ◽  
Milk Yield ◽  
Fat Content ◽  
Holstein Cows ◽  
Milk Productivity ◽  
Black And White ◽  
The Third ◽  
Fat Yield ◽  
Selection Of

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%.

scholarly journals PHL 417: a zirconium-rich pulsating hot subdwarf (V366 Aquarid) discovered in K2 data

2020 ◽  
Vol 499 (3) ◽  
pp. 3738-3748
Author(s):  
R H Østensen ◽  
C S Jeffery ◽  
H Saio ◽  
J J Hermes ◽  
J H Telting ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Helium Abundance ◽  
The Sun ◽  
The Third ◽  
Short Period ◽  
Standard Models ◽  
Hot Subdwarfs ◽  
Amplitude Mode ◽  
Rare Group

ABSTRACT The Kepler spacecraft observed the hot subdwarf star PHL 417 during its extended K2 mission, and the high-precision photometric light curve reveals the presence of 17 pulsation modes with periods between 38 and 105 min. From follow-up ground-based spectroscopy, we find that the object has a relatively high temperature of 35 600 K, a surface gravity of $\log g / {\rm cm\, s^{-2}}\, =\, 5.75$ and a supersolar helium abundance. Remarkably, it also shows strong zirconium lines corresponding to an apparent +3.9 dex overabundance compared with the Sun. These properties clearly identify this object as the third member of the rare group of pulsating heavy-metal stars, the V366-Aquarii pulsators. These stars are intriguing in that the pulsations are inconsistent with the standard models for pulsations in hot subdwarfs, which predicts that they should display short-period pulsations rather than the observed longer periods. We perform a stability analysis of the pulsation modes based on data from two campaigns with K2. The highest amplitude mode is found to be stable with a period drift, $\dot{P}$, of less than 1.1 × 10−9 s s−1. This result rules out pulsations driven during the rapid stages of helium flash ignition.

scholarly journals Search for dormant black holes in ellipsoidal variables III. The OGLE BULGE short-period sample

2021 ◽  
Author(s):  
Roy Gomel ◽  
Simchon Faigler ◽  
Tsevi Mazeh ◽  
Michał Pawlak
Keyword(s):  
Main Sequence ◽  
Compact Object ◽  
Close Binaries ◽  
Periodic Modulation ◽  
Mass Ratio ◽  
True Nature ◽  
The Third ◽  
Short Period ◽  
Actual Mass

Abstract This is the third of a series of papers that presents an algorithm to search for close binaries with massive, possibly compact, unseen secondaries. The detection of such a binary is based on identifying a star that displays a large ellipsoidal periodic modulation, induced by tidal interaction with its companion. In the second paper of the series we presented a simple approach to derive a robust modified minimum mass ratio (mMMR), based on the observed ellipsoidal amplitude, without knowing the primary mass and radius, assuming the primary fills its Roche lobe. The newly defined mMMR is always smaller than the actual mass ratio. Therefore, a binary with an mMMR larger than unity is a good candidate for having a massive secondary, which might be a black hole or a neutron star. This paper considers 10,956 OGLE short-period ellipsoidals observed towards the Galactic Bulge. We re-analyse their modulation and identify 136 main-sequence systems with mMMR significantly larger than unity as candidates for having compact-object secondaries, assuming their observed periodic modulations reflect indeed the ellipsoidal effect. Obviously, one needs follow-up observations to find out the true nature of these companions.

Population characteristics of daughters of domestic and foreign breeding bulls

2021 ◽  
Vol 1 (2) ◽  
pp. 29-35
Author(s):  
N. I. Abramova ◽  
◽  
O. L. Khromova ◽  
M. O. Selimyan ◽  
◽  
...  
Keyword(s):  
Genetic Structure ◽  
Milk Yield ◽  
Population Characteristics ◽  
Breeding Value ◽  
Black And White ◽  
Vologda Region ◽  
Breeding Work ◽  
White Breed ◽  
Productive Traits ◽  
Modern Population

The use of foreign-bred bulls leads to changes in the genetic structure of the black-and-white breed population, which affects the level of population characteristics. The study was conducted to study the comparative variability and heritability of productive and reproductive characteristics of daughters of sires of domestic and foreign selection in pedigree livestock 10 250 cows 1st calving modern population of black-motley breed of the Vologda region. The superiority of the offspring of foreign bulls in the average indicators of all the studied traits was established with confidence (P<0,001). There were no significant differences in the level of variability of the characteristics of the descendants of domestic and foreign bulls. According to productive traits, the greatest variability of indicators was established for milk yield for 305 days of the 1st lactation Cv = 17,3 – 17,7%, therefore, selection on this trait will be more effective. The greatest share of the influence of bullsfathers, both domestic and foreign selection, in the total sum of all factors determining the value of traits in the population of the black-and-white breed, is determined by the milk yield of daughters η2 = 0,22 – 0,24, the age of the 1st fruitful insemination and the first calving η2 = 0,24 – 0,25. In further breeding work with the breed, it is necessary to obtain and use domestic producers that exceed the breeding value of foreign bulls.

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