How To Calculate Milk Production Per Cow

Managing Cow Lactation Cycles

Poor feeding management of cows tin pb to shorter, lower yielding lactations and increase calving interval. This written report by John Moran from Asia Dairy Network explains the changing feed requirements of cows over the lactation cycle and how to match this with moo-cow genetics.

18 May 2015

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The lactation cycle

Cows must calve to produce milk and the lactation cycle is the menstruation betwixt ane calving and the next.

The bicycle is divide into four phases, the early on, mid and late lactation (each of about 120 days, or d) and the dry menstruation (which should last as long as 65 d). In an ideal world, cows calve every 12 months.

A number of changes occur in cows as they progress through different stages of lactation.

Likewise as variations in milk product, there are changes in feed intake and trunk condition, and phase of pregnancy. Effigy 1 presents the interrelationships between feed intake, milk yield and live weight for a Friesian cow with a fourteen month inter-calving interval, hence a 360 d lactation.

Following calving, a cow may start producing 10 kg/d of milk, rise to a peak of 20 kg/d by nigh vii weeks into lactation then gradually fall to 5 kg/d by the end of lactation.

Although her maintenance requirements will not vary, she will demand more than dietary energy and protein every bit milk production increases and so less when production declines. However to regain torso status in belatedly lactation, she will require additional energy.

Cows usually use their own trunk status for almost 12 weeks subsequently calving, to provide energy in addition to that consumed. The free energy released is used to produce milk, allowing them to achieve higher elevation production than would be possible from their diet solitary.

To practice this, cows must have sufficient torso condition available to lose, and therefore they must take put it on late in the previous lactation or during the dry flow.

From calving to peak lactation
Milk yield at the peak of lactation sets up the potential milk production for the year; one extra kg per twenty-four hour period at the peak tin can produce an extra 200 kg/cow over the unabridged lactation.

There are a number of obstacles to feeding the herd well in early lactation to maximise the elevation. The foremost of these is voluntary nutrient intake.

At calving, appetite is only about 50 to 70 per cent of the maximum at top intake. This is because during the dry menses, the growing calf takes up space, reducing rumen volume and the density and size of rumen papillae is reduced.

Later calving, information technology takes time for the rumen to "stretch" and the papillae to regrow. It is not until weeks 10-12 that appetite reaches its full potential.

Peak lactation to peak intake
Following tiptop lactation, cows' appetites gradually increment until they tin can consume all the nutrients required for product, provided the nutrition is of high quality. From Figure 1, cows tend to maintain weight during this stage of their lactation.

Mid and belatedly lactation
Although energy required for milk product is less demanding during this period because milk production is failing, energy is still of import because of pregnancy and the need to build up trunk condition as an energy reserve for the next lactation. It is generally more efficient to improve the condition of the herd in late lactation rather than in the dry catamenia.

Dry flow
Maintaining (or increasing) body condition during the dry period is the key to ensuring cows accept acceptable body reserves for early lactation.

If cows calve with adequate body reserves, they tin can cycle within 2 or iii months after calving. If cows calve in poor status, milk production suffers in early lactation considering body reserves are not available to contribute energy.

In fact, dietary free energy tin can be channelled towards weight gain rather being fabricated bachelor from the desired weight loss. For this reason, high feeding levels in early lactation cannot make up for poor body condition at calving.

Persistency of milk product throughout lactation

The ii major factors determining total lactation yield are peak lactation and the rate of reject from this top. In temperate dairy systems, total milk yield for 300 day lactation can exist estimated by multiplying peak yield by 200.

Hence a cow peaking at xx litres per twenty-four hour period (50/d) should produce 4000 L/lactation, while a peak of 30 L/d equates to a 6000 L full lactation milk yield. This is based on a rate of refuse of 7 to eight per cent per month from peak yield, that is every month the moo-cow produces, on boilerplate, 7 to 8 per cent of peak yield less than in the previous calendar month.

This level of persistency is the target for well managed, pasture-based herds in temperate regions.

Actual values tin can vary from 3 to iv per cent per calendar month in fully fed, lot fed cows to 12 per cent or more than per month in very poorly fed cows, for instance during a severe dry out season following a good wet season in the tropics.

The rate of decline from tiptop, or persistency, depends on:
• height milk yield
• nutrient intake following peak yield
• torso condition at calving
• other factors such every bit disease condition and climatic stress

More often than not speaking, the higher the milk yield at peak, the lower its persistency in percentage terms.

Underfeeding of cows immediately post-calving reduces pinnacle yield but also has adverse furnishings on persistency and fertility. Dairy cows have been bred to use body reserves for boosted milk production, but high rates of alive weight loss will delay the onset of oestrus.

Underfeeding of high genetic merit cows in early on lactation is one of the biggest nutritionally induced problems facing many small holder farmers in the humid tropics, because they often exercise not accept the necessary improvements in feeding systems to utilise high genetic potential.

If imported high genetic quality cows are non well fed, milk product is compromised, but of more importance, they will not wheel until many months postal service-calving.

Theoretical models of lactation persistency

Tabular array 1 and Effigy 2 present data for milk yield over 300 twenty-four hours lactations in cows with diverse peak milk yields and lactation persistencies.

Such data provides the footing of herd direction guidelines for dairy systems with 12 month calving intervals. Depending on herd fertility, hence target lactation lengths, like guidelines could be developed for xv or 18 month calving intervals.

Table one and Effigy ii only nowadays information for cows with peak yields of fifteen, xx and 25 50 milk/24-hour interval.

Modest holder dairy farms in the humid tropics with proficient feeding and herd management should exist able to accomplish 15 L/twenty-four hours peak yield, and for those with high genetic merit cows, xx or 25L/day is realistic.

Lactation persistencies of less than 8 per cent per calendar month may be achievable in tropical dairy feedlots but more realistic persistencies are the 8 to 12 per cent per calendar month presented in the Table 1 and Effigy 2.

Virtually every small holder farmer records daily milk yield of his or her cows, then they know peak yield and can easily decide the monthly rate of turn down, providing a simple monitoring tool to appraise their level of feeding direction.

Unless feeding management tin can be improved, it may be better in the long run to import cows of lower genetic merit.

For example, importers may asking "5000 L cows" (that is cows that peak at 25 L/day under expert feeding management, with a persistency of 8 per cent/mth).

If, through poor feeding, their persistency is reduced to 12 per cent per month, 300 d lactation yields are merely 3900 L and they practise non cycle for many months after calving, "4000 L cows" may be a better investment. From Table 1, such cows would produce similar milk yields if they could be fed to 8 per cent per month milk persistency and they are more than likely to bicycle earlier.

Impacts of curt lactation length

Poor feeding direction of potentially high yielding cows can create many problems.

Lactation anoestrus tin can occur as the cows are forced to apply more of their body reserves in early lactation. This can lead to low peak milk yields and shortened lactation lengths.

Cows volition dry off prematurely if they receive insufficient feed nutrients to maintain feasible processes of milk production in their mammary tissue.

The bear on of decreasing lactation lengths on 300 day lactation milk yields and average daily milk yields are presented in Tabular array 2. These information are based on the aforementioned persistency data used in Table 1. The penalties for these shortened lactation lengths are presented in Table iii.

Compared to x month lactations, inherently poor yielding cows with low acme milk yields can lose 20 to 160 L milk through but 9 months milking or 90 to 360 50 milk if but milking for viii months.

Post-obit higher tiptop milk yields, this volition increase to penalties of xxx to 270 Fifty milk for 9 calendar month to 120 to 600 L for 8 month lactation lengths. This can have a big effect on the herd'due south rolling herd average which can exist reduced past 0.3 to 2.0 L/cow/mean solar day for the extreme values presented in Table 2 and 3.

These tables are based on 300 twenty-four hours lactation lengths, that is nether an ideal situation where cows calve down every 12 months.

Inter-calving intervals are more likely to be 13, 14 or 15 months, hence lactation lengths should be even longer than 300 days.

Ideally cows should be managed to accept a two month dry out period to allow the mammary tissue to recuperate before the next lactation. Yet, lactation lengths of just viii months followed by dry periods of another 8 months are all too common in many tropical small holder dairy farms. This then equates to only l per cent of the adult cows milking at whatever 1 time.

Source: https://www.thecattlesite.com/articles/4248/managing-cow-lactation-cycles/

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