scholarly journals COW REPRODUCTION FEATURES UNDER THE CONDITIONS OF INDUSTRIAL TECHNOLOGY OF MILK PRODUCTION

2021 ◽  
Vol 250 ◽  
pp. 207-213
Author(s):  
A. A. Velmatov ◽  
◽  
I. M. Dunin ◽  
T. N. Tishkina ◽  
◽  
...  
Keyword(s):  
Milk Production ◽  
Industrial Technology ◽  
Calving Interval ◽  
Dry Period ◽  
Milk Productivity ◽  
The Third ◽  
Reproductive Ability ◽  
Service Period ◽  
Negative Effect

Milk productivity of cows depends on the duration of the service period. Thus, with an increase of the service period from 60 to 121 days after the first calving, milk productivity of cows increases by 937 kg (P≥0.95), after the second calving - by 745 kg and after the third calving - by 926 kg (P≥0.95). Cows with a service period of less than 60 days had the lowest milk productivity of 6751 kg. Cows with a service period of more than 120 days gave 7688-8251 kg of milk. Milk productivity of cows is also influenced by the length of the dry period. Too short, as well as too long dry period has a negative effect on milk productivity. So, cows with a dry period of less than 40 days gave an average of 7011 kg of milk, with an increase of the dry period, milk productivity parameters increase. Cows with a dry period of 41-50 days produced 7465 kg, with a dry period of 51-60 days - 7785 kg, with an increase of the dry period from 61 to 70 days milk productivity increased to 8042 kg, finally, dry period of over 70 days leads to a decrease of milk productivity of cows up to 7211 kg. In terms of the calving interval, the experimental cows corresponded to the parameters of highly productive cows, being within the period of 12-14 months. The analysis of reproductive ability showed that the animals have average values for reproductive ability.

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.

scholarly journals Influence of reproductive qualities on dairy productivity of cows of the Simmental breed

2021 ◽  
Vol 285 ◽  
pp. 04005
Author(s):  
Maria Grinchuk ◽  
Yulia Nesterova
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Mass Fraction ◽  
Milk Protein ◽  
Production Performance ◽  
Dry Period ◽  
Milk Productivity ◽  
Service Period ◽  
Positive Effect ◽  
Different Levels

The aim of work is to explore influence of first fruitful insemination, service period and dry period to dairy productivity of Simmental cows. The research is aimed at studying the milk production of Simmental cows with different levels of reproductive qualities. The result of the research, a relation was established between the age of the first fruitful insemination, the duration of the service period, the duration of the dry period and milk production performance. It has been established that the age of the first fruitful insemination at 18-24 months has the most beneficial effect on subsequent milk production. The service period of 90-120 days has a positive effect to an increase in milk yield per 305 days of lactation, the longer service period negatively affects to the mass fraction of fat. With an increase in the duration of the dry period, the mass fraction of fat increases, but milk yield decreases. The influence of reproductive qualities to the milk protein is negligible. It was revealed that the age of the first insemination at 18-24 months is the most profitable for production. According to the results of the research, it can be judged that reproductive qualities, in combination with other factors, affect the milk productivity of Simmental cows.

scholarly journals Reproductive qualities of dairy cows at different levels of milk yield

2021 ◽  
Vol 22 (4) ◽  
pp. 589-596
Author(s):  
Svetlana V. Titova
Keyword(s):  
Milk Yield ◽  
Correlation Coefficients ◽  
Comparison Method ◽  
Reproductive Capacity ◽  
Calving Interval ◽  
Milk Productivity ◽  
Reproductive Ability ◽  
Service Period ◽  
The Impact ◽  
Different Levels

The article presents the results of the analysis of the reproductive ability of cows depending on the level of their milk productivity. The studies were conducted in the Republic of Mari El on cows of the Holstein black-and-white breed (n = 3828). There have been studied the influence of different levels of milk yield on the duration of the service period and period between calvings, the output of calves per 100 cows, the coefficient of reproductive ability. The studies used the comparison method, correlation, regression and one-factor analysis of variance. It has been established that the milk yield increases with the age of cows, but at the same time the duration of the service period and calving interval increases. In first-calf cows, the service period was 128.8 days (Cv = 75.1 %), the calving interval was 403.6 days (Cv = 23.5 %). By the third lactation, with an increase in milk yield by 1030 kg (15.4 %), the duration of the service period increased by 7.2 days (5.6 %), the calving interval  -by 12.3 days (3.0 %). The share of the impact (ƞ2x) of milk yield on the duration of the service period was 5.4 %, the calving interval -4.7 %. The correlation coefficients between milk yield for 305 days of the first lactation and the duration of the service period and calving interval were 0.24 and 0.22 (p<0.05), with milk yield for the entire lactation 0.81 (p<0.05). The optimal indicators of the service period (89.4 days), the calving interval (369.4 days), the reproductive capacity (0.94) and the output of calves (1.0) were possessed by the first heifers with low milk productivity-milk yield less than 5000 kg of milk. In animals with the milk yield of 6000-9000 kg of milk or more, the duration of the service period was 12.4-249.6 % higher, the calving interval -by 1.9-32.5 % (p<0.05). According to the regression coefficients, on average, each increase in milk yield per 1000 kg increased the duration of the service period by 25.9 days, the calving interval -by 23.1 days, which worsened the output of calves by 0.24 %, and the coefficient of reproductive ability decreased by 16.0 %.

scholarly journals THE ASSESSMENT OF THE ADAPTABILITY OF JERSEY BREED COWS

2020 ◽  
Vol 60 ◽  
pp. 61-70
Author(s):  
N. Pelekhaty ◽  
D. Kucher ◽  
O. Kochuk-Yashchenko ◽  
A. Lypianets
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Milk Fat ◽  
Reproductive Capacity ◽  
Milk Productivity ◽  
Significant Deterioration ◽  
Reproductive Ability ◽  
Service Period ◽  
Jersey Cows ◽  
Adaptation Index

The results of the studies carried out highlight the assessment of the adaptive ability of Jersey cows. The conditions of keeping Jersey cows in the Dan Milk subsidiary contribute to the realization of high milk productivity, which is due to heredity, but cause a deterioration in their reproductive capacity. At the same time, a high manifestation of milk productivity and satisfactory reproductive ability have observed only in the daughters of DJ Jante 302761 – whose adaptation index was closer to zero and amounted to -2.7. The force of influence (ηx2) of paternal origin on the signs of milk production in first-calf calfs was 21.1% versus 5.9% of the generalized mean value for cows belonging to the line. It has been founded that according to the adaptation index, the state of animals those characterized by the absence of harmonious interaction with the environment – cows show high productivity with a significant deterioration in reproductive capacity, which indicates the presence of a feedback between these characteristics. It was found not high enough, but statistically significant influence (P < 0.01 – P < 0.001) on the adaptation level of first-calf cows by milk yield for 305 days of lactation (8.0%), milk fat and protein (7.0%). A statistically significant effect (ηx2 = 82%) of the signs of reproductive ability of cows (service period and period between calving) was found depending on their level of adaptation (P < 0.001). With an increase in the level of milk production of cows, was established a clear connection between the deterioration of the adaptive qualities of livestock. So with an increase in milk yield for the entire lactation from 6000 to 10000 kg of milk, the adaptation index decreases from -0.5 to -9.5, which is confirmed by a statistically significant difference between the extreme groups of animals with different levels of productivity (P < 0.001). According to the adaptation index, the condition of animals were characterize by the lack of harmonious interaction with the environment - cows show high milk productivity with a significant deterioration in reproductive capacity, which indicates the inverse relationship between these traits. The influence of the father and belonging to the lines on such indicators of milk productivity as: yield for 305 days of lactation, milk fat and protein (P < 0.05 – P < 0.001) was statistically significant. Significant effect of increasing the level of milk yield of cows was observed on such signs of reproductive capacity as: service period, period between calves and reproductive ability coefficient (P < 0,001). There was no statistically significant effect of belonging to the lines and offspring of specific breeders on the signs of reproduction of cows in general (P > 0.05). We found that the reproductive quality of cows is more influenced by the level of milk yield of cows during lactation (23.1%, at P < 0.001), which is confirmed by our previous studies. The conditions of keeping Jersey cows in the Dan Milk State Enterprise contribute to the realization of high milk productivity, which is due to heredity, but causes a deterioration in their reproductive capacity.

scholarly journals Reppoductive ability of ukrainian black and white dairy cows

2016 ◽  
Vol 18 (2) ◽  
Author(s):  
M. I. Kuziv ◽  
E. I. Fedorovych
Keyword(s):  
Milk Yield ◽  
Milk Fat ◽  
Reproductive Capacity ◽  
Dry Period ◽  
Black And White ◽  
Reproductive Ability ◽  
Service Period ◽  
Lactation Duration ◽  
The Impact ◽  
Period Duration

The major components of economically useful traits in cattle dairy productivity, which conducted the selection is milk productivity and reproductive ability of cows. Studies conducted on animals Ukrainian black and white dairy cattle in the «Milk River» farm in the Sokal and Brody offices breeding reproducers «Breeder» Lviv region and plant breeding «Yamnytsya» Ivano–Frankivsk region. Ukrainian black and white dairy breed in the western region of Ukraine is characterized by good reproductive ability. Depending on the husbandry and lactation duration, service period lasted within 87.4 – 121.5 day, intercalving period – within 364 – 402.6 day, dry period within – 47.3 – 72.9 day, the fertility index was 46.3 – 48.0, coefficient of reproductive ability – within 0.92–0.99,  output of calves per 100 cows – within 91.8 – 98.8. The duration of pregnancy in cows of different  farms and lactations were in range 277 – 283.5 day and meet the requirements of the physiological norm. It has been shown that the milk yield of cows depends on the parameters of reproductive capacity. The correlation between duration of service–period and intercalving period, and milk yield, milk fat in most cases was positive. Correlation dry period duration and parameters of milk yield changed from negative to positive. Depending on the husbandry, lactation and index the impact share of service–period duration on milk yield was 7.0 – 29.7, for intercalving period – 8.8 – 31.8, for dry period – 9.2 – 23.8% respectively.

scholarly journals Lactive activities and the process of milking of first-calf cows using robotic milking

2020 ◽  
Vol 17 ◽  
pp. 00038
Author(s):  
Lenar R. Zagidullin ◽  
Rifat R. Khisamov ◽  
Rubin R. Kayumov ◽  
Igor V. Lomakin ◽  
Nadezhda M. Kanalina
Keyword(s):  
Milk Production ◽  
Lactation Period ◽  
Milk Productivity ◽  
The Third ◽  
Average Productivity ◽  
Maximum Decrease ◽  
Robotic Milking

Studies have been conducted to assess the lactation productivity of first-calf cows of Kholmogory breed of Tatarstan type using robotic milking systems. The following changes in the amount of milking over the course of 10 months of lactation were observed: during the first month, the cows were milked the least number of times, which was 75, or 2.4 times per day. During the second month, they were milked 86 times (2.8 per day). By the 4th month, milking reached a peak of 93 times (3 per day). By the 5th month, a decline was observed (by 11 % compared to the 4th month). The average number of milking times per day was 2.8 ± 0.05 times. The amount of milking is closely correlated with milk productivity: twicemilked cows had an average productivity of 15.3 kg, 3 times – 19.0 kg, and 4 times – 27.0 kg (r = 0.69). The milking robot spent approximately 108 seconds, or 29 % of the time spent in the milking box, on preparation activities, including: udder cleaning, 39 seconds; scanning the position of the utter, 21 seconds; and connecting milking cups, 48 seconds. Lactation took most of the time, namely 251 seconds, or 66 %. The peak milk production takes place during the second month of lactation, 681.3 kg. By the third month, a decline was observed by 4.8 %, to 648.1 kg. The maximum decrease in milk production by 12.4 % occurred between the 5th and 6th month of the tested lactation period.

scholarly journals Reproductive qualities and milk productivity of black-and-white cows depending on sire lineage

2020 ◽  
Vol 50 (5) ◽  
pp. 47-55
Author(s):  
S. L. Belozertseva ◽  
L. L. Petrukhina
Keyword(s):  
Milk Yield ◽  
Research Work ◽  
Live Weight ◽  
Reproductive Capacity ◽  
Calving Interval ◽  
Milk Productivity ◽  
Black And White ◽  
Service Period ◽  
Significant Difference

The paper presents the results of studying the effect of sire lineage on reproductive qualities and milk yield of cows. The study was carried out inIrkutskregion on a herd of Holsteinized black-andwhite cattle of Pribaikalsky type. The analysis of the main characteristics of reproductive capacity of herd cows on a farm was performed during 2013–2018. The material of the research work was based on the informational database of animals from the program of breeding register Selex. Cows were divided according to sire lineage and milk productivity into five groups by the level of milk yield: from 5000 to6500 kg, 6501-8000, 8001-9500, 9501-11000 and more than11001 kg. Successful insemination of heifers took place at the age of 15.7-16.6 months with the live weight of more than400 kg, which corresponds to zootechnical standards. The earliest (15.7 months) insemination was in heifers of Reflection Sovereign sire line, the age of first calving was 753 days with the live weight of561 kg. The latest (498 days) successful insemination was observed in heifers of Montvik Chieftain bull line with the live weight of498 kg. Cows of Sealing Trygen Rocket (8766 kg) and Reflection Sovereign (8704 kg) sire lines had the highest milk productivity with a significant difference (p ≥ 0.90). The cows of these lines had the longest service period (164 and 179 days), as well as the length of the calving interval (445 and 458 days), respectively. The coefficient of reproductive capacity of cows of different sire lines ranged from 0.80 to 0.88, which is a low indicator.

scholarly journals PRODUCTIVITY OF COWS OF UKRAINIAN BLACK-AND-WHITE AND RED-AND-WHITE DAIRY BREEDS

2018 ◽  
Vol 51 ◽  
pp. 112-118
Author(s):  
V. V. Machulnyi
Keyword(s):  
Dairy Cattle ◽  
Dairy Cows ◽  
Milk Production ◽  
Milk Yield ◽  
Fat Content ◽  
Reproductive Capacity ◽  
Black And White ◽  
Reproductive Ability ◽  
Service Period ◽  
Dairy Breed

Milk yield of cows in breeding herds, Cherkassy region, for last completed lactation averaged 6442 kg of milk with 3.62 % fat content. Currently the question of interconnection of cows’ milk production and reproductive capacity is especially important, because the significant increase in milk yields makes minimize calves. The successful conduct of breeding had set the goal to detect the best options for combining milk production and reproductive ability of animals.To characterize the level of milk production including reproductive ability of cows we used indicator of daily average milk yield per one day of periods between calving (PBC). The best service period can be considered period of 51-90 days, that allows you to get one calf per cow per year (average PBC is 351 days) and maintain high milk production (6431 ± 39.6 kg during 305 days of lactation). With this service period all indicators of milk production and reproductive ability are at high level. Reduced service period below recommended levels will reduce the duration of lactation and milk production, and increasing service period will increase the duration of lactation with a simultaneous reduction in milk production for 305 days. Herewith deterioration of reproductive ability is marked and manifested in the increase of the insemination index, decline in the reproductive capacity, increase of periods between calving and as a result, reduce of calves and culling barren cows.Analysis of genealogical structure of the studied herds points to low diversity (Ukrainian Black-and-White dairy cows belong to 6 lines and Ukrainian Red-and-White dairy cows – to 8 ones) with high affinity (by Chief 1427381.62 to R. Sovereign 198998 bloodline, by Starbuck 352790.79 to Elevation 1491007 and Ideal1013415 bloodlines).Genealogical structure of the herds is saturated a lot of bulls genealogical groups of Holstein cattle: Chief 1427381 – 11 bulls in the array of Ukrainian Black-and-White dairy breed and 5 ones in Ukrainian Red-and-White dairy breed, Starbuck 352790.79 – 10 sires in the array of Ukrainian Black-and-White dairy cattle and 3 ones in Ukrainian Red-and-White dairy breed, Elevation 1491007.65 – 4 sires in the array of Ukrainian Black-and-White dairy cattle and 3ones in Ukrainian Red-and-White dairy breed.Currently the sires of Chief 1427381.62 (7712-3,76-289,9-3,14-242,1), Starbuck 352790 (7857-3,87-295,4-3,07-241,2), Jocko Besne 694028588.94(6687-3,88-259,5-3,03-202,6), and Bell 1667366 bloodlines (61341-3,95-242,3-3,02-185,2) among sires of Ukrainian Black-and-White dairy cattle and the sires of Cavalier 1620273.72 (7285-3,98-289,9-3,08-224,4), Chief 1427381.62 (7522-3,76-282,8-3,00-225,7),Starbuck 392405 (7667-3,87-296,7-3,00-230,0), and Elevation 1491007.65 bloodlines (7544-3,80-286,7-3,5-230,0) among sires of Ukrainian Red-and-White dairy breed are classified to a highly productive and promising for breeding and wider use by productive qualities.After the first insemination the lowest proportion of fertilized cows is among offspring belonging to Chief 1427381 bloodline which is only 38 % among both breeds. However, the milk yield of breeding stock belonging to this bloodline is 7712 kg with 3.76 % fat content for Ukrainian Black-and-White dairy cows and 7522 kg of milk with 3.76 % fat content for Ukrainian Red-and-White dairy cows. Daughters belonging to Elevation1491007, Valiant 1650414, and Hanover 1629391 bloodlines with yields of 4566-5478 kg of milk per lactation had a part of fertilized cows, after the first insemination, at the level of 41-49 %. Fertilization after the first insemination above 50% was in daughters belonging to Cavalier 1620273.72 (52%), Starbuck 392405(50-55 %), Bell 1667366(56%) and Jocko Besne 694028588.94 bloodlines (64 %). The level of performance of these animals for milk yield ranged from 6134 kg to 7857 kg.Heritability coefficients of milk yield and duration of service period were low (0.118-0.289). A positive correlation can be explained by the fact that extension of service period (to a certain level) leads to growing number of milking days (duration of lactation) and defers a decrease in productivity of cows by physiological reasons, namely as a result of pregnancy. Low rates of heritability indicate little genetic diversity of traits and the significant influence of physiological and environmental factors in their formation.As Ukrainian Black-and-White and Ukrainian Red-and-White dairy breeds have a high proportion of heredity of Holstein breed which has genetically large fetus, there is need to study the characteristics of nature passing calving in cows of these breeds. Itis found the number of first-calf heifers which needed help was 52.4%. Animals calve alone in 47.6 % of all cases. Calving was without complications if the live weight of calves not exceeding 6-7% of mother’s weight. The cows calved without help of staff exceeded by 11.7% of the width of the pelvis in the buttocks, 7.5 % of the width of the ilium, and 7.1 % of its oblique length compared with animals of same age.

The First Lactation Yield as a Basis for Selection as Compared with the Second and Third Lactations

1955 ◽  
Vol 1955 ◽  
pp. 102-108 ◽  
Author(s):  
Ivar Johansson
Keyword(s):  
Environmental Influences ◽  
Production Capacity ◽  
Nutritional State ◽  
Calving Interval ◽  
Preliminary Evaluation ◽  
Dry Period ◽  
The Third ◽  
White Cattle

In an earlier publication (Johansson and Hansson, 1940) it was shown that under the management conditions of the Red-and-White Cattle in Sweden the dam-daughter correlation was considerably higher for the first lactation yield than for the second, and it was also somewhat higher than that for the third lactation. The second lactation yield was found to be much more sensitive to variations in length of the preceding calving interval, or dry period, than was the yield in the later lactations, and probably it is also more sensitive to environmental influences. The yield during the first lactation is influenced by the age and the nutritional state of the cow at calving, but here no preceding dry period enters in as a variable. It was concluded that a preliminary evaluation of the production capacity of the cow can safely be based on her first lactation yield. Furthermore it was suggested that even when records are available for two or more lactations of a cow, the record for the second lactation should not be considered.

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