How Long Can You Milk a Jersey Cow Without Getting Pregnant Again
Featured Articles
Managing Moo-cow Lactation Cycles
18 May 2015
Poor feeding management of cows can lead to shorter, lower yielding lactations and increase calving interval. This study past John Moran from Asia Dairy Network explains the changing feed requirements of cows over the lactation cycle and how to lucifer this with moo-cow genetics.
The lactation bicycle
Cows must calve to produce milk and the lactation wheel is the menstruum between one calving and the adjacent.
The bike is split into four phases, the early, mid and late lactation (each of nigh 120 days, or d) and the dry menses (which should last every bit long as 65 d). In an ideal globe, cows calve every 12 months.
A number of changes occur in cows as they progress through different stages of lactation.
Besides as variations in milk production, at that place are changes in feed intake and torso status, and stage of pregnancy. Figure 1 presents the interrelationships between feed intake, milk yield and alive 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, rising to a peak of 20 kg/d past virtually vii weeks into lactation then gradually fall to v kg/d by the cease of lactation.
Although her maintenance requirements will non vary, she volition demand more dietary free energy and protein as milk production increases and so less when production declines. However to regain trunk condition in tardily lactation, she will require boosted energy.
Cows commonly use their own trunk condition for about 12 weeks later on calving, to provide energy in addition to that consumed. The energy released is used to produce milk, allowing them to achieve higher peak production than would exist possible from their diet lone.
To do this, cows must have sufficient body condition available to lose, and therefore they must have put it on tardily in the previous lactation or during the dry period.
From calving to elevation lactation
Milk yield at the top of lactation sets up the potential milk production for the twelvemonth; one extra kg per twenty-four hours at the superlative can produce an extra 200 kg/moo-cow over the entire lactation.
There are a number of obstacles to feeding the herd well in early on lactation to maximise the acme. The foremost of these is voluntary food intake.
At calving, appetite is only well-nigh 50 to 70 per cent of the maximum at peak intake. This is because during the dry catamenia, the growing dogie takes up space, reducing rumen volume and the density and size of rumen papillae is reduced.
Subsequently 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.
Meridian lactation to peak intake
Following peak lactation, cows' appetites gradually increase until they can consume all the nutrients required for production, provided the diet is of high quality. From Figure 1, cows tend to maintain weight during this stage of their lactation.
Mid and late lactation
Although energy required for milk production is less demanding during this menstruum because milk product is failing, energy is still important because of pregnancy and the need to build upwards body 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 out period.
Dry catamenia
Maintaining (or increasing) trunk condition during the dry period is the key to ensuring cows take acceptable body reserves for early lactation.
If cows calve with adequate body reserves, they can cycle within two or 3 months after calving. If cows calve in poor condition, milk production suffers in early lactation because body reserves are not available to contribute energy.
In fact, dietary energy tin can be channelled towards weight gain rather being made available from the desired weight loss. For this reason, loftier feeding levels in early lactation cannot make upwardly for poor body condition at calving.
Persistency of milk production throughout lactation
The two major factors determining full lactation yield are summit lactation and the rate of decline from this peak. In temperate dairy systems, total milk yield for 300 twenty-four hours lactation can be estimated past multiplying peak yield past 200.
Hence a cow peaking at 20 litres per 24-hour interval (50/d) should produce 4000 Fifty/lactation, while a tiptop of 30 L/d equates to a 6000 L total lactation milk yield. This is based on a rate of decline of 7 to 8 per cent per month from peak yield, that is every month the 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 can vary from three to 4 per cent per month in fully fed, lot fed cows to 12 per cent or more per calendar month in very poorly fed cows, for instance during a severe dry season post-obit a proficient moisture flavour in the tropics.
The charge per unit of pass up from superlative, or persistency, depends on:
• peak milk yield
• nutrient intake following top yield
• body condition at calving
• other factors such equally disease status and climatic stress
Generally speaking, the college the milk yield at peak, the lower its persistency in percentage terms.
Underfeeding of cows immediately postal service-calving reduces peak yield just also has agin effects on persistency and fertility. Dairy cows have been bred to utilize body reserves for boosted milk production, but high rates of live 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 bug facing many minor holder farmers in the humid torrid zone, because they often practise not have the necessary improvements in feeding systems to employ high genetic potential.
If imported high genetic quality cows are not well fed, milk production is compromised, but of more importance, they will non bicycle until many months post-calving.
Theoretical models of lactation persistency
Tabular array 1 and Figure two present data for milk yield over 300 day lactations in cows with various peak milk yields and lactation persistencies.
Such information provides the footing of herd management guidelines for dairy systems with 12 month calving intervals. Depending on herd fertility, hence target lactation lengths, similar guidelines could exist adult for 15 or 18 month calving intervals.
Table 1 and Figure 2 merely present data for cows with acme yields of 15, 20 and 25 Fifty milk/24-hour interval.
Small holder dairy farms in the humid tropics with adept feeding and herd management should be able to achieve 15 L/twenty-four hour period superlative yield, and for those with high genetic merit cows, xx or 25L/twenty-four hour period is realistic.
Lactation persistencies of less than viii per cent per month may be achievable in tropical dairy feedlots but more realistic persistencies are the 8 to 12 per cent per month presented in the Tabular array 1 and Figure ii.
Most every small holder farmer records daily milk yield of his or her cows, then they know peak yield and can easily make up one's mind the monthly rate of decline, providing a elementary monitoring tool to assess their level of feeding management.
Unless feeding management can be improved, it may be improve in the long run to import cows of lower genetic merit.
For example, importers may request "5000 L cows" (that is cows that height at 25 Fifty/twenty-four hour period under skilful feeding management, with a persistency of viii per cent/mth).
If, through poor feeding, their persistency is reduced to 12 per cent per month, 300 d lactation yields are simply 3900 50 and they do not wheel for many months afterwards calving, "4000 50 cows" may be a meliorate investment. From Tabular array 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 cycle before.
Impacts of curt lactation length
Poor feeding management of potentially loftier yielding cows tin can create many issues.
Lactation anoestrus can occur as the cows are forced to employ more of their body reserves in early lactation. This tin lead to low peak milk yields and shortened lactation lengths.
Cows will dry out off prematurely if they receive insufficient feed nutrients to maintain viable processes of milk production in their mammary tissue.
The impact of decreasing lactation lengths on 300 day lactation milk yields and average daily milk yields are presented in Table 2. These data are based on the aforementioned persistency information used in Tabular array ane. The penalties for these shortened lactation lengths are presented in Tabular array 3.
Compared to x month lactations, inherently poor yielding cows with low peak milk yields tin lose xx to 160 L milk through simply nine months milking or xc to 360 L milk if merely milking for 8 months.
Following higher peak milk yields, this volition increase to penalties of 30 to 270 50 milk for 9 calendar month to 120 to 600 L for 8 calendar month lactation lengths. This can have a big effect on the herd'south rolling herd average which tin can be reduced by 0.iii to 2.0 Fifty/cow/solar day for the farthermost values presented in Table two and 3.
These tables are based on 300 day lactation lengths, that is under an platonic situation where cows calve downward every 12 months.
Inter-calving intervals are more probable to be 13, 14 or fifteen months, hence lactation lengths should be fifty-fifty longer than 300 days.
Ideally cows should be managed to have a ii calendar month dry period to allow the mammary tissue to recuperate earlier the next lactation. Nevertheless, lactation lengths of just eight months followed by dry periods of another 8 months are all besides common in many tropical modest holder dairy farms. This then equates to only fifty per cent of the adult cows milking at whatsoever one time.
Source: https://www.thecattlesite.com/articles/4248/managing-cow-lactation-cycles/
0 Response to "How Long Can You Milk a Jersey Cow Without Getting Pregnant Again"
แสดงความคิดเห็น