The uniformity of lactation is judged by the following indicators. Milk productivity of farm animals. Evaluation of milk production
The purpose of the lesson. To study methods of accounting and indicators for assessing the milk productivity of cows. Master the evaluation procedure and criteria for selecting cows for milk production.
Equipment and visual aids. Card of a breeding cow (2-MOL), milk yield register, act of control milking (4-MOL).
An important biological feature of cattle is the ability of cows to give milk (lactate) for a long time.
lactation called the period from the time of calving of a cow to the start of her dead wood. The average duration of lactation is 305 days. During lactation, the amount of daily milk yield undergoes significant changes. After calving, daily milk yields increase, reaching a maximum at the end of the first - beginning of the second month, and, starting from the sixth month of lactation, milk yields begin to decrease (the fetal need for nutrients increases).
The time when milk production stops is called launch .
The period from the moment of launch to the next calving - dry period.
Service periodis the time from calving to fruitful insemination of a cow.
Interhotel period– time from one calving to another.
For the efficient and most economical use of cows, it is necessary that the intercalving period is one year, that is, it is considered biologically expedient when a calf is produced from a cow every year. In this regard, the duration of the dry period should not exceed 60 days, and lactation - 305 days, the service period - should not exceed 80 days. The annual functional cycle of a dairy cow is shown in Figure 2.
Rice. 2 Optimal annual cycle of use of dairy cows.
During lactation, milk yields in cows are not the same. Each cow has its own individual changes in milk yield. All changes in the amount of milk allocated for individual days, months can be represented in the form of a lactation curve (a graphical representation of milk yield per lactation). The nature of the lactation curve in cows is not the same. In some, it changes little during lactation, while in others it is subject to drastic changes. The lactation curve is determined by the level of milk production and the individual characteristics of the physiological state of cows, as well as the level of feeding and keeping conditions. There are four types of cows according to the nature of lactation activity (Fig. 3):
1. High sustainable lactation. Cows of this type give a lot of milk and digest food well. It is peculiar to cows with a strong constitution, with high milk productivity.
2. High unstable lactation activity decreasing after receiving the highest daily milk yield and rising again in the second half of lactation (two-peak type). Peculiar to constitutionally weak cows.
3. High but unstable, rapidly falling. After reaching the highest milk yield, it decreases sharply and for lactation is low. Cows of this type have a weak cardiovascular system, not adapted to long-term work with high stress, such cows should be culled.
4. Sustained low lactation. Cows of this type have low milk yields and are subject to culling.
Cows are evaluated by milk yield: per calendar or business year, per lactation. The amount of milk yield of cows per lactation or year can be determined by daily accounting and summing up daily milk yields. But this is very labor intensive. Therefore, a method of control milkings at certain intervals has been proposed: after 5, 10, 15, 20 and 30 days. When determining milk yield in cows on the basis of control milkings, it is assumed that milk yield changes little between control days. At the same time, it was established that the shorter the interval between control milkings, the more accurately milk yield can be determined. Milk yield for the period between control milkings is calculated by multiplying the amount of milk produced on the control day by the number of days in the period. The sum of milk yields for individual periods is the milk yield per lactation.
In breeding farms, milk yield is recorded every ten days (every 10 days), and in commodity farms - monthly. In conditions of full feeding, the difference in milk yield for 305 days of lactation according to control milkings and taking into account daily milk yield is ± 1-1.5%, monthly - ± 3-4%. This error is insignificant, therefore, to facilitate accounting, control milkings are used instead of daily accounting.
When rearing calves by suckling, the milkiness of cows is taken into account as follows: the calf is allowed to approach the cow and allowed to suck from only one half, usually the left, of the udder, and milk is milked and measured from the other (right). At the same time, the amount of milk from the left and right halves of the udder is always approximately the same. In this regard, the received milk yield from the right half of the udder is multiplied by two and thus the milk yield from the entire udder is determined. According to such control milkings, milk yield for lactation in cows of specialized meat breeds is determined.
The milk productivity of cows is estimated by the quantity and quality of milk received from them over a certain period of time.
At the same time, quantitative, qualitative and economic indicators are taken into account.
Quantitative indicators of milk productivity:
- milk yield per lactation, indicating the number of days of lactation;
- milk yield for 305 days of lactation (determined during the evaluation of cows);
- milk yield per lactation period (by quarters, per month, etc.);
- milk yield for the best three lactations, lifelong milk yield (determined during the evaluation of cows);
- the highest daily milk yield;
- gross milk yield (by group of cows, farm, household);
Quality indicators of milk:
- average percentage of fat, protein in milk per lactation
Average percentage of fat, (protein), % = ,
where: 1% milk - multiplying the milk yield of each month of lactation by the content of fat (protein) in this month;
- amount of milk fat per lactation(305 days of lactation) is determined by the formula:
The amount of milk fat, (protein), kg,
It has been established that the cow's milk yield per lactation depends on the highest daily milk yield by about 25% and on the nature of the decrease in lactation activity by 75%. In cows of abundant dairy breeds, after reaching the maximum milk yield, the decrease in the level of milk productivity in the subsequent months of lactation was 6%, in unproductive ones - 9-12% per month. The nature of lactation activity is judged by its stability. To do this, define coefficient of constancy (stability) of lactation.
In highly productive cows with pronounced high milk yields, the coefficient of lactation constancy reaches 90-99%, in cows with rapidly decreasing milk yields - 70-80%.
Coefficient of constancy of lactation, %
where: P 1 - milk yield for the first three months of lactation (1,2,3);
P 2 - milk yield for the next three months of lactation (4,5,6).
The coefficient of usefulness of lactation,%
In cows with even lactation, the lactation usefulness factor is 80% or more, with decreasing lactation - 50% or less.
Guidelines
on conducting laboratory classes and performing independent work for students of the veterinary faculty on the topic:
"Accounting for milk productivity"
N.Novgorod 2014
Nizhny Novgorod State Agricultural Academy
Department of Private Zootechnics and Farm Animal Breeding
Guidelines for conducting laboratory classes and performing independent work for students of the veterinary faculty on the topic " Accounting for milk production» N.Novgorod, 2014
Artists:
Doctor of Agricultural Sciences, Head of the Department of Private Zootechnics and Breeding of Farm Animals Basonov Orest
Antipovich
Candidate of Agricultural Sciences, Art. Lecturer at the Department of Private Zootechnics and Breeding of Farm Animals Muryanova Elena
Leonidovna
Reviewers:
Doctor of Biological Sciences, Professor Department of Private Animal Science and Breeding of Farm Animals Krasavtsev Yury Fedorovich
Doctor of Agricultural Sciences, Professor of the Department of Animal Feeding Vorobieva Natalya Viktorovna
Topic 3. Accounting for milk production.
The purpose of the lesson: to learn how to determine the value of milk productivity of cows for a month, for 305 days of lactation, for a calendar year. Familiarize yourself with the method of calculating the content of fat and protein in cow's milk. Acquire practical skills in determining milk yield per feed cow.
Determination of milk yield of cows according to Kalantar and Wilson. Determination of payment for feed with milk.
The productivity of farm animals is the quantity and quality of products obtained from an animal over a certain period. It is determined by heredity and depends on species, breed,
age, individual characteristics of the animal. Genetically determined productivity can only be obtained under favorable conditions for feeding and keeping animals.
Milk is a biological fluid of complex chemical composition.
which found about 250 components.
The main indicators characterizing milk productivity are
are:
Milk yield (kg) for the lactation period, for the entire lactation, for 305 days;
The amount of milk fat, protein (kg);
Mass fraction of fat and protein in milk (%).
Accounting for products in animal husbandry is much more complicated than in other industries, especially when it comes to accounting for milk productivity, this is mainly due to the fact that dairy farming requires individual accounting of productivity for each cow: daily by the control milking method, monthly, for lactation, for 305
days per calendar year. During the same periods, the amounts of milk,% fat and protein are determined.
In a year, milk yield is controlled 30 times from each cow, % of fat in milk is 19, % of protein in milk is 10; 10 times are calculated per month and 10 times with a cumulative total.
Figure #1. Optimal annual cycle for dairy cows
Milk is one of the main livestock products.
most agricultural producers in our country.
Why is it necessary to keep individual records of the productivity of cows?
1. First of all, in order to identify the best and worst cows, the best ones are left for further breeding, the worst ones are culled.
2. On the basis of accounting for the productivity of cows, milk production plans are drawn up for farms, for farms, they determine the volume of marketable products and the flow of funds to the settlement account of the enterprise.
3. To determine the wages of farm workers.
Methods for accounting for milk production
On livestock farms and complexes, there are two ways to account for milk productivity:
1. Group
2. Individual
Group way- this is a method in which the amount of milk received from a group of cows assigned to one milkmaid is determined. It is needed mainly to determine wages, feed consumption per group and to summarize the results of work and determine the flow of funds.
Individual way- this is a method in which the productivity of each cow is determined separately. It is necessary to determine the breeding value of the animal. The individual milk productivity of cows is estimated according to data for the entire lactation, for the first 305
days of lactation, for the calendar year and for the whole life. The standard duration of lactation is 305 days.
These two methods are used on farms simultaneously.
Methods for determining individual productivity
1. Daily accounting
The milk yield of cows per lactation or year can be determined by daily weighing (carried out in breeding farms). This is the most accurate account. But he is very labor intensive.
2. Control milking method
The first control milking is carried out not earlier than six days after calving. Usually control milking with three milkings starts at noon, and with two milkings - in the evening. The amount of milk on the day of control is determined by summing up single milk yields - morning, lunch and evening. The first day of the control period is the first day after calving. The last day of the control period is the first day of the one-shot start-up milking.
The milk yield of cows is taken into account in kilograms with an accuracy of 0.1 kg. If the account is kept in liters, they are converted to kilograms by multiplying by the density
(for bulk milk, you can use the average density -
Control milkings are carried out at certain intervals:
5, 10, 15, 20 and 30 days. When determining milk yield in cows on the basis of control milkings, it is assumed that milk yield changes little between control days. At the same time, it was established that the shorter the interval between control milkings, the more accurately milk yield can be determined. Milk yield for the period between control milkings is calculated by multiplying the amount of milk produced on the control day by the number of days in the period. The sum of milk yields for individual periods will be the milk yield for lactation.
Most farms use the method of control milking,
which are usually carried out every ten days (every 10 days). Milk yield for each control day is multiplied by 10 (they get milk yield for a decade); the sum of these three products gives the milk yield for the corresponding month of lactation.
For example, on the day of control, May 3, 2000, the daily milk yield of cow Vetka was 15.3 kg, after 10 days (May 13) - 19.0 kg, on May 23 - 14.8 kg.
According to these data, the cow's milk yield for May will be 491 kg.
(15.3×10)+(19×10)+(14.8×11). The assessment of the cow will be much less accurate if the control milkings are carried out once a month (to determine the milk yield per month, the milk yield for the control day is multiplied by 30).
3. According to the highest daily milk yield (according to Wilson)
To determine the milk yield per lactation, you can use the Wilson coefficient, which found that if the highest daily milk yield is multiplied by
200, then we get milk yield for lactation of cows of dairy breeds, and if by 180 - then for cows of combined breeds. However, this simplified method has large errors and therefore has not been widely used.
For example, if the maximum daily milk yield of a cow was 20 kg, then
the expected milk yield for lactation will be approximately 4000 kg
4. For three adjacent months of lactation (according to Kalantar)
Accounting for the annual milk yield for individual periods of lactation by multiplying the milk yield for any three-month period of lactation by the appropriate coefficient (table).
Table - Calculation of the annual milk yield of cows by the method of Professor Kalantar
Total milk yield |
Coefficient for |
Annual milk yield |
|
lactation |
for 3 adjacent |
Professor Kalantar |
|
5. Method for the first 90 days
Having data on the value of milk yield for the first 90 days, the productivity of the first heifer for lactation is predicted. Possible milk yield for 305 days or for the entire first lactation is determined by multiplying the actual milk yield,
obtained from a first-calf heifer for 90 days of lactation, on a transfer
coefficient, which is preliminarily calculated according to the materials of a particular herd or by an average coefficient of 2.45.
Determining the amount of milk from a cow per lactation does not yet fully indicate its productivity. You also need to know the content of fat and protein in milk. Milk fat and milk protein content
are the most important indicators of milk quality. With an increase in the content of fat and protein in milk, its nutritional value and
taste qualities, the production of butter, cheese, cottage cheese and other fermented milk products is increasing.
To determine fat and protein in milk in one of the control milkings (on the 5th, 15th, 25th of each month), let's say on the 15th, together with the determination of milk yield - they take milk samples (lunch, evening, morning) all three times in one bottle and determine the percentage fat and protein in milk on a centrifuge or on the device "Lactan". They write down - the number of the cow, the name of the milkmaid. For example, 3.8% was determined. Then the amount of milk milked per day (350 kg) is multiplied by its fat content (3.8%) = 350 kg x 3.8 = 1330 - this is
one percent milk.
At the end of lactation one percent milk for all months of lactation add up, the amount one percent milk(1%) of milk is divided by the amount of milk yield per lactation, this determines the average percentage of fat in the animal for the entire lactation. For example, 16000: 4200 = 3.81%
Amount of milk fat determine: from the sum data
one percent milk(1%) milk divided by 100, 16000: 100 = 160 kg of milk fat. If data are available for lactation milk yield and average fat percentage, then the amount of milk fat can be found. For example, 5000 kg of milk multiplied by 3.9% = 19500: 100 = 195 kg of milk fat.
To compare cows in terms of milk production, especially in the scientific
research works calculate the corrected milk yield with 4% fat content according to the formula:
MCW = M x (0.4 + W x 0.15)
M is the amount of milk; W - actual % fat in milk;
0.15 - constant coefficient;
For example, milk yield for lactation -5000 kg, % fat - 4.6
MKZH \u003d 5000 x (0.4 + 4.6 x 0.15) \u003d 5450 kg.
Milk yield consistency coefficient (KPU)
Milk yield consistency ratio is the drop in milk yield compared to
the highest monthly milk yield.
They start with the fact that among the monthly milk yields they find the highest milk yield, this milk yield is taken as 100%, then they take the milk yield of the next month and express it as a% of the previous one. For example: the second month milk yield - 450 kg - 100%,
the next third - 400 kg, the fourth - 360 kg, the 5th - 300 kg, etc.
then they take 400 kg for 100% |
||||
then take for 100% - 360 |
||||
Only the last two months of lactation are not taken into account.
All results are summed up (89 + 90 + 83, etc.) and the sum is divided by the number of months that were processed. The difference between 100 and the received KPU is the average coefficient of milk yield reduction by months of lactation.
It is desirable that it be not lower than 95%, i.e. milk yield decreased by an average of no more than 5%.
The stability of lactation is determined by the indicator of usefulness (PP)
proposed by Veselovsky V.B. according to the formula:
Actual milk yield x 100
Highest daily milk yield x number of lactation days
If lactation is even, then PP = 70% or more, in cows with a sharply decreasing lactation, PP is less than 50%.
In addition, the following indicators are used to characterize and analyze the productive qualities of cows, the intensity of their use and milk production:
Milk yield per 100 kg of live weight (milk ratio), which is calculated by the formula:
KM \u003d Y x 100
Where Y is the milk yield for lactation, LW is the live weight of cows;
- the amount of milk produced per 1 feed unit, or the number of feed units spent on the production of 1 kg of milk;
- the amount of milk produced per unit area of agricultural land (or arable land).
At cows of the dairy type, the coefficient of milk production is over 800 kg, mo-
meat and meat type from 601 to 800 kg, meat and milk type 600 kg and below.
Change in milk yield of cows during lactation
Month of lactation |
Milk for 305 |
||||||||||
milk days |
|||||||||||
The formation of milk is a complex reflex process that occurs in the mammary gland. It is regulated by both the nervous and humoral systems. Blood substances are used to form milk.
The time from the calving of a cow to the cessation of milk production is called the lactation period, and the cessation of milk production is called the start. The time from launch to the next calving is the dry period.
The milk productivity of cows is characterized by the quantity and quality of milk received over a certain period of time; per lactation, calendar year, as well as for a number of lactations. In addition, in some cases, the lifetime productivity of animals is taken into account.
Evaluation of milk production
Evaluation of cows for milk productivity is carried out according to milk yield (kg), fat content in milk (%) or the amount of milk fat (kg) for 305 days of lactation or for a shortened lactation. With shortened lactation, the actual milk yield is taken into account and the duration of lactation in days is indicated. Control milking of cows is carried out at least once a month.
The average fat content of milk for the first 305 days of lactation or for shortened lactation is determined according to the results of systematic determinations, which are carried out once a month. It is calculated by multiplying the percentage of fat in milk for each month by the monthly milk yield, the products are added (getting the amount of one percent milk per lactation) and the sum is divided by the actual milk yield for the same months.
The amount of milk fat per lactation (kg) is determined by dividing the amount of 1% milk by 100.
First-calf heifers are evaluated by milk yield for the completed lactation, cows of two calvings - by average productivity for two lactations, mature cows - by average productivity for any three lactations.
In commercial farms, in the absence of data for previous years, it is allowed to evaluate cows according to the last completed lactation.
The average milk fat content of cows, when assessed by their productivity for a series of lactations, is calculated by summing up the milk yields expressed in one percent milk for lactations taken into account (305 days or shortened) and dividing this amount of one percent milk by the actual amount of milk produced for the same lactations.
To determine the properties of milk flow in the 2-3rd months of lactation, control milking of cows is carried out during the day. During the control milking, the value of a single milk yield (kg) and the time spent on each milking (min) are taken into account.
The average milk flow rate is determined in kg / min by dividing the amount of milk produced per day (kg) by the time spent (min). The results of monitoring the properties of milk flow of cows are recorded in a special sheet.
Lactation and lactation curve
The mammary gland, unlike other glands of external secretion, functions intermittently, but at certain periods, determined by the physiological state of the cow. The period from calving to launch is called lactation.
During lactation, milk yields in cows are not the same. All changes in the amount of milk allocated for individual days, months can be represented as a lactation curve. The nature of the lactation curve in cows is not the same.
The lactation curves of cows at the beginning of lactation are characterized by increasing secretion of milk. At the same time, the highest daily milk yield is manifested in the second or third months of lactation, and for low-productive ones - even in the first month. With the onset of pregnancy, milk secretion begins to decline rapidly, and at the end of lactation it stops altogether.
Factors affecting milk production
The amount of milk that cows give per lactation depends on hereditary and a number of other factors. The most important of them: breed characteristics, feeding and maintenance, age, dry period, age of the first mating, weight, milking and some others.
Heredity and breed characteristics determine the potential productive capabilities of animals. An animal of one breed or another has its own limit of productivity, due to heredity. Therefore, the problem of creating highly productive breeds and improving less productive ones is always in the focus of breeders' attention.
For example, the milk productivity of Black-and-White breed animals averages 5,000 kg, while the productivity of Caucasian brown cattle is only 3,000-3,500 kg.
The number and order of milkings have a significant impact on milk productivity, especially of highly productive and new-calving cows. Milking and massage, while training the udder, simultaneously affect the intensification of the work of the whole body of the cow. During the preparation of a cow for milking, irritation of the central nervous system and pituitary gland occurs. The latter releases the hormone oxytocin. The action of the hormone (facilitating the act of milking) lasts 4-5 minutes. Therefore, the rate of milking has some influence on the amount of daily milk yield and fat content in milk. It should also be borne in mind that with appropriate training of animals, their transfer from three-time to two-time milking does not cause a significant decrease in milk yield, and labor costs are noticeably reduced.
The milk productivity of cows also depends on their age, and up to the fifth or sixth lactation, cows' milk yields usually increase, then for several years they are maintained at approximately the same level, after which they decrease. There is a certain, hereditarily determined regularity in the nature of changes in daily milk yield during lactation. A visual representation of this is given lactation curve. In dairy cattle breeding, three forms of the lactation curve have been established: uniform, rhythmic, and rapidly falling. A uniform lactation curve is characterized by relative constancy, that is, an increase in daily milk yield over 3 months, and then a gradual, without any disruption, decrease. The specificity of the rhythmic lactation curve lies in the fact that high milk yields for several days alternate with lower ones with a generally relatively uniform course of the curve. With a rapidly falling lactation curve, milk yield, having reached a maximum, then sharply decreases. The feeding and maintenance of livestock has an extremely great influence on milk production. The level of feeding affects not only during the lactation period of cows, but also in an earlier period of their growth and development. If during the entire period of rearing the animals received optimal diets with a sufficient content of protein, minerals, microelements, then their development proceeded normally, and after the first lactation such animals are able to give a large amount of milk.
It is also known that with an increase in milk yield, the consumption of feed nutrients for products decreases. Therefore, the better the feeding of dairy cows, the cheaper the milk will be.
All cows of dairy breeds have a positive relationship between live weight and their productivity. Shorter or longer periods of the dry period adversely affect milk productivity in the upcoming lactation. Depending on the age, fatness and productivity of the cow, the normal dry period usually lasts 50-65 days. The level of milk productivity also depends on the duration of the service period. An average of 85 days is considered optimal (with fluctuations depending on the level of productivity and the health of the cow). With a shortened service period, milk yield for a given lactation decreases.
The milk production of cows can also be affected by calving time. In conditions of constant good feeding in the suburban area, relatively uniform calving of cows throughout the year is desirable. In areas more distant from the city, if there are good pastures, spring calving is advisable, since cheap pasture fodder can be used to the maximum. The state of health of cows also has a significant impact on the value of milk productivity. Normal productivity can only be shown by perfectly healthy animals, which are distinguished by the good development of the whole organism and are capable of producing offspring annually. Another of the conditions for increasing the milk productivity of animals is the specialization of breeds in the dairy direction.
A rather objective indicator of milk productivity is the milk yield coefficient, it shows how much milk is produced per lactation per 100 kg of live weight.
KM = (Milk per lactation / live weight) *100
KM = (4880/500) * 100 = 976
Our herd has an average milk yield of 976
Calculation of milk of basic fat content:
M b = (M f * F f) / F b
M b - produced milk of actual fat content per year: per cow; for the whole herd.
F f - actual fat content of milk
F b \u003d 3.4% - basic fat content of milk
M b \u003d (4880 * 3.7) / 3.4 \u003d 5278
Requirements for milk upon acceptance to dairies
According to GOST 13624-88, milk obtained from healthy cows is allowed for acceptance. This must be confirmed by a certificate of veterinary and sanitary well-being of supplying farms, issued by a veterinary specialist for a period of not more than one month ago.
Milk should be free of foreign odors, non-frozen homogeneous liquid, without flakes, white or slightly yellow in color, density not less than 1.027 g/cm3, temperature not more than 10°C.
Milk not to be accepted:
obtained in the first and last 7 days of lactation;
counterfeit (skimmed, diluted with water or skimmed milk, with the addition of neutralizing and preservative components);
polluted;
with acidity above 22 ° T.
Table 5.1
Milk productivity of cows and sale of milk to the state
Since the fat content of milk is 3.7%, which is 0.3% more than the base fat, this allows us to obtain an additional amount of milk in terms of the base fat content.
The content and methodology of the lesson. Control over milk productivity is the most important element in the overall set of measures to take into account the breeding and productive qualities of cows. The milk productivity of cows is assessed by the quantity and quality of milk received from them over a certain period of time, more often during lactation. Standard duration of lactation is 305 days (Fig.5) Dry period Lactation (305-320 days) (45-60 days) Calving Fertilization Launch Service period 80 days Pregnancy 285 days 365 days Fig.5. The annual cycle of a cow's activity The following methods are used to account for milk production per lactation. 1. Daily accounting (carried out in breeding farms) 2. Accounting for milk yield by control milkings with an interval of 10-15 days. 3. Accounting for the annual milk yield according to the highest one-day and daily milk yield by Professor Wilson's method (daily milk yield x by a factor of 200). 4. Accounting for the annual milk yield for individual periods of lactation by multiplying the milk yield for any three-month period of lactation by the corresponding coefficient (Table 9). Table 9 - Calculation of the annual milk yield of cows by the method of Professor Kalantar Coefficient of months of lactation Milk yield for 3 months 3 21 PDF created with FinePrint pdfFactory Pro trial version www.pdffactory.com In most farms, the amount of milk produced from a cow is determined by measuring its volume in a milk meter. In this case, in order to convert liters to kg, you need to multiply the amount of milk in liters by its density. When assessing milk productivity, along with quantitative indicators, qualitative indicators are also determined, such as the coefficient of lactation constancy. The coefficient of lactation constancy is determined by the formula F.F. Eisner. A CPL = B* n where A is the actual milk yield per lactation, kg; B - the highest daily milk yield, kg; n is the number of days of lactation To characterize and analyze the productive qualities of cows, the intensity of their use and milk production, the following indicators are used: milk yield per 100 kg of live weight (milk ratio) according to the formula: Y * 100 KM = ZhM where Y is milk yield per lactation ; LW – live weight of cows Dairy-type cows have a milk-production ratio of over 800 kg, milk-meat type from 601 to 800 kg, meat-and-milk type 600 kg and below. As an average indicator of the intensity of use of cows in the herd, the milk yield per forage cow for a certain period of time is calculated. To do this, the gross milk yield for the accounting period is divided by the average number of forage cows for the same period. The number of forage cows is calculated either by counting their feeding days or by calculating the average number of cows. The first method, although more accurate, is more laborious. Therefore, it is advisable to use it when calculating milk yield per forage cow for a short period of time. When calculating milk productivity for longer periods of time, the average number of cows for a given period is calculated. To do this, the number of cows at the beginning and end of each month is summed up and the resulting amount is divided by the number of terms. For example, the average annual number of forage cows is calculated using the formula in which the number of cows on the same date should be put down instead of the date: (1/I+1/II)+(1/II+1/III)+(1/III+1/ IV)+…+(1/XI+1/XII)+(1/XII+1/I) 24 22 PDF created with FinePrint pdfFactory Pro trial version www.pdffactory.com Fat and protein content of milk is determined once a month cows (%). To calculate the average content of fat (or protein) in milk for any period of time, the milk yield for this period is multiplied by the percentage of fat (or protein) and the amount of one percent (respectively in fat or protein) milk is obtained. By dividing the amount of 1% milk by the amount of natural milk, the average percentage of fat (or protein) in milk over that period is obtained. To calculate the total amount (kg) of milk fat (or protein) obtained from a cow for a particular period of time, the amount of one percent milk according to the corresponding indicator is divided by 100. When milk is delivered to a dairy plant, a calculation is made with the supplier in terms for basic fat content according to the formula: Kf * Zhf Kmb \u003d Zhb. where kmb. – quantity of milk of basic fat content, kg; Kf - the amount of milk of actual fat content, kg; Zhf. – actual fat content of milk, %; Zhb. - basic fat content of milk, % Task 1. Calculate the number of forage cows and milk yield per cow from the beginning of the year according to the following indicators (for calculating the production report for the farm in f.24-mol.). Task 2. Determine the average fat content in cow's milk for lactation. Months of lactation For lactation Production I II III IV V VI VII VIII IX X milk Milked 380 430 390 370 360 355 350 340 300 260, kg Fat content in milk 3.9 3.6 3.6 3.7 3.8 3.9 4.0 4.1 4.3 4.3 loque, % 1% milk Average fat content in milk, % 23 PDF created with FinePrint pdfFactory Pro trial version www.pdffactory.com Topic 6. Morphological and functional properties of the udder of cows The purpose of the lesson: to study the methodology for evaluating cows for suitability for machine milking according to the development of the udder and the properties of milk flow. Teaching aids and materials: 1. Izilov Yu.S. Livestock practice. - M. : Agropromizdat, 1988, p.202-208. 2. Soldatov A.P., Tabakova L.P., Tabakov G.P. Workshop on the technology of milk and beef production. –M.: Kolos, 1999, p.34-40. 3. Cherkashchenko I.I., Spivak M.G. Functions of the udder of cows. – M.: Kolos, 1979, p.96-116. 4. Vernier caliper, caliper, measuring tape, stopwatch. 5. Posters on the topic. The content and methodology of the lesson. The development of the udder and its qualitative characteristics are the most important indicators that judge the suitability of cows for machine milking. For this purpose, the following are studied: 1) morphological features: the shape and size of the udder, its glandularity, the size of the teats and their shape and location; 2) functional properties: duration and intensity of milking, simultaneous milking of udder quarters and uniform development of udder quarters. Morphological and functional properties of the udder in cows are assessed after the 1st and 3rd calving during the first three months of lactation, but not earlier than 15 days after calving. Morphological assessment of the udder is carried out by inspection, palpation and measurement 1-1.5 hours before milking. To measure the udder, a measuring tape, a compass and a caliper are used, with the help of which the following measurements of the udder are taken at certain points (Fig. 6). 24 PDF created with FinePrint pdfFactory Pro trial version www.pdffactory.com Fig.6. Measurements of the udder of cows 1. BV - girth of the udder - along the horizontal line of the udder at the level of the base of the front edge (tape); 2. BV - the length of the udder - from the rear bulge to its front edge at the base (compass); 3. D - the greatest width of the udder - under the teats of the anterior lobes (compass); 4. DE, ZZh - depth of the anterior and posterior quarters - vertically from the abdominal wall to the base of the nipple (with a ribbon); 5. LCD, EI - the length of the anterior and posterior nipple - from the base to the tip (with a tape or caliper); 6. L1, L2 - girth of the anterior and posterior nipples - with a tape, at the base of the nipple. 7. I1, I2 - the diameter of the anterior and posterior nipple - in the upper third (with a caliper); 8. - the distance from the lower edge (bottom) of the udder to the ground (ribbon); 9. – distance between the anterior nipples (tape) (at points I – right, I – left); 10. IR - the distance between the anterior and posterior nipples (tape); eleven. - the distance between the rear nipples (tape) (at points K - right, K - left). Important for the normal development of the udder, its suitability for machine milking is its attachment to the belly of the cow. Since a drooping udder makes it difficult for the cow to move, it is difficult to milk it with a machine and is more likely to be mechanically damaged. The distance from the lower edge (bottom of the udder) to the ground is at least 45-50 cm. The structure of the udder is assessed by probing it in all directions before and after milking. There are glandular, medium glandular and fleshy or fatty udders. 25 PDF created with FinePrint pdfFactory Pro trial version www.pdffactory.com The glandular udder is fine-grained in its structure, after milking it becomes soft, spongy and falls off strongly, forming small skin folds behind (udder reserve). The teat walls of such an udder are usually thin and elastic. The udder, medium in glandularity, has a coarse-grained structure. The milked udder falls moderately, forming several large folds of skin behind. A fleshy or fatty udder is characterized by highly developed connective and adipose tissues. After milking, it almost does not decrease in volume, and when touched, it remains elastic, with tight-fitting skin. The walls of the nipples are rough. The prominence of blood vessels, assessed by the saphenous udder veins and abdominal veins, can be good, moderate or weak. A clear expression and a strong branching of the veins indicate a good development of the udder and is associated with intensive blood circulation. It is known that for the formation of 1 kg of milk, 400-500 liters of blood must pass through the udder. The shape of the udder is characterized by its length, width and depth. The shape of the udder is bowl-shaped, rounded and goat. The bowl-shaped udder is wide and deep, extended forward; it has the shape of an oval and with a large area of attachment to the abdomen. The rounded udder is somewhat narrowed, the area of its attachment to the stomach is relatively small, the nipples are usually somewhat close together. The goat udder is characterized by underdeveloped anterior or strongly hypertrophied and drooping posterior teats, sharply demarcated by a lateral furrow. In terms of size, a large udder is distinguished with a girth of 120 cm or more, medium - 110-119 cm and small - less than 110 cm. In most cows, the udder posterior lobes are better developed than the anterior ones, but it is necessary to take into account the degree of spread of the udder forward under the belly. This can be established (Fig. 7): a) by the distance from the front edge of the udder to the vertical line lowered from the outermost protrusion of the ilium (maklok); 26 PDF created with FinePrint pdfFactory Pro trial version www.pdffactory.com b) from the leading edge of the udder to the umbilical cord. Fig.7. The degree of spread of the udder forward under the belly It is desirable that this distance be 4-8 cm in first-calf heifers, 6-10 cm in adult cows. This furrow is formed due to insufficient development of the glandular and supporting connective tissues. A clearly defined furrow is undesirable, since the udder in this case decreases in volume and becomes inflamed more often. Therefore, when assessing the udder, the severity of the furrow separating it or the lobation of the udder is noted: weak severity of the separating furrow, medium and strong. When machine milking cows, the size, shape and location of the teats are of great importance. In this case, nipples that are too thick (more than 3.2 cm in diameter), long (more than 9 cm), short (less than 4 cm) and thin (1.8 cm in diameter) are undesirable. The anterior nipples are usually 1-1.5 cm longer than the posterior ones, their desired length is 6-8 cm. Nipples are distinguished by shape: cylindrical, conical, bottle-shaped, pear-shaped, pencil-shaped (thin, long), funnel-shaped (thick, conical ). The most desirable nipples are cylindrical or slightly conical in shape. The normal distance between the ends of the anterior nipples is about 15-18 cm, the ends of the posterior ones are more than 6-10 cm, between the anterior and posterior nipples is 8-12 cm. slightly or strongly inclined forward, as well as to the sides. It is desirable that the nipples point downwards. To determine the functional properties of the udder, a special control milking is carried out. Milking is carried out using conventional or special machines. It is also necessary to strictly observe the procedure for preparing cows for milking and their milking. 1. Productivity of individual parts of the udder. The amount of milk given out from different quarters of the udder is determined using a special apparatus. The productivity of the front and rear udders is judged by the udder index: a) the amount of milk from the front lobes x 100% the amount of milk from the hind lobes b) the amount of milk from the front lobes x 100% the amount of milk from all lobes The udder index is desirable at least 43 %. 2. Duration of milking of individual shares. The simultaneity of milking is determined by the difference in the end time of milk release from the first and last quarters of the udder. Milk ejection is simultaneous – the difference in milking duration does not exceed 40 s. and non-simultaneous - the difference in the duration of milking exceeds 40 s. 3. Milking intensity or milk flow rate. Determined using a stopwatch, using a conventional milking machine for milking. The minimum requirements for one-time milk yield when assessing the rate of milk yield is 4 kg, daily milk yield is 10 kg. The duration of milking is measured with a stopwatch, starting from the moment the first streams of milk appear until the end of the machine milking of the cow. To determine the average intensity of milk yield, milk yield per day is divided by the time spent on milking and expressed in kg/min. 4. The degree of milking in the first 3 minutes. It is expressed as a percentage of the total milk yield. 5. Completeness of lactation or milk yield. Set according to the ratio of the amount of milk from manual milking and the total amount of milk. The overall assessment of the udder is carried out according to the results of its morphological assessment and assessment of functional properties. 28 PDF created with FinePrint pdfFactory Pro trial version www.pdffactory.com 29 PDF created with FinePrint pdfFactory Pro trial version www.pdffactory.com 40 PDF created with FinePrint pdfFactory Pro trial version www.pdffactory.com
Animal productivity- the output of products obtained from one animal for a certain period of time (day, month, quarter, year, etc.).
The productivity of farm animals characterizes the level of development of a particular branch of animal husbandry and is the most important factor in increasing the production of livestock products.
Main part The volume of production received from the breeding stock of livestock is accounted for by milk. Gross milk yield includes milk from all cows. Milk sucked by calves is not included in gross milk yield.
Milk given to young, is an element of production costs for raising livestock. The milk sucked by the calf is included in the value of the reared calf and is reflected in the gross output of rearing. Milk can be measured in volume units (liters) or weight (kg, c, t) units.
If information is presented in volumetric units, for example in liters, then to convert to mass units, the number of liters of milk is multiplied by a factor of 1.03, which is the density of this product.
Milk production is the main indicator of the productivity of dairy herd cows and an auxiliary indicator of the productivity of beef cows used for suckling calf rearing. When determining the average milk productivity, cows of specialized meat breeds with suckling calves, as well as cows actually used for group suckling calf rearing, and cows culled for fattening and slaughter are excluded from the total number of cows.
Indicators milk productivity of animals reflect an important aspect of animal husbandry, its quality level and can be considered for a day, month, year and other periods of time, and are also calculated by age and sex groups of different types of farm animals.
Milk production indicators include:
Average monthly and average annual milk yield per average monthly or average annual cow of a dairy herd;
Average annual milk yield per dairy cow;
Average milk yield per dairy cow during lactation.
Milk production of cows is measured milk yield from one average annual cow and is determined by the formula:
where - gross milk yield (kg, t);
is the average number of cows.
With milk yield from one average annual cow, the indicator allows us to assess the achieved level of organization of dairy cattle breeding, i.e. the degree of use of cows in the process of reproduction of cattle and the overall level of productivity of the dairy herd. Index average milk yield per dairy cow characterizes the actual level of milk productivity of cows and is determined by the formula:
where is the average annual number of dairy cows.
More accurately, the milk productivity of cows reflects the indicator average milk yield per dairy cow during lactation , which is calculated by the formula:
where is the average milk yield per dairy cow;
- the average number of dairy cows for the lactation period.
The period of milking a cow from the time of her last calving to the "start" before a new calving is called the lactation period and is approximately 10 months (about 300 days). The time from "launch" to new calving, during which the cow is not milked, is called the dry period.
Average daily milk yield milk during the calendar year can be calculated using the formula:
where is the duration of the lactation period, days.
Average daily milk yield from one cow has significant seasonal fluctuations and, when plotted graphically in a coordinate system, forms a lactation curve. The essence lies in the fact that usually during the first and second months of lactation, the daily milk yield of cows consistently increases, reaching a climax at the end of the second - beginning of the third month, and then the milk yield gradually (by 5-6% monthly) decreases. Knowing the characteristic features of the lactation curve allows you to more accurately plan the gross milk production for any period of the calendar year.
Milk production is concentrated in all categories of farms in the agricultural sector of the agro-industrial complex, while all agricultural organizations in Belarus without exception have a significant number of cows and are engaged in milk production.
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