Shortened dry cow periods
Gabriella VargaPennsylvania State University
Why a dry period?Why a dry period?
Recommended as a “rest” period
Based on observations that milk production decreased when no dry period was allowed
To allow adequate mammary tissue regrowth before the next lactation
The majority of the studies used historical data
Optimizing dry period length
Although no income is collected directly during the dry period, managing the length of the dry period may play a crucial role in maximizing profits for both current and upcoming lactations.
Why 60 days dry?
Regeneration of the mammary gland Two to three weeks are needed for
secretory cell growth in the late dry period This is essential for maximum colostrum
production and milk secretion in the next lactation
Observations that this resulted in maximum milk production
Mammary gland development
Regression and repair of the digestive tract
Ruminal papillae may partially regress as a result of feeding lower energy diets during the early dry period
Allows for repair of ruminal ulcers that may have developed
in the previous lactation
Dry period length
56 d 28 d
Dry matter intake, kg/d 14 16.8Milk yield, kg/d 42.3 91Fat,% 3.86 4.08Protein, % 2.83 2.97
No effect on calf weight or colostral quality
Rastini and Grummer, 20030-70 DIM
planned dry period
30 day 60 day
Schairer et al, 2001 11,635 10, 222
Bachman, 2002 9,799 9,978
Gulay et al, 2003 9,580 9,836
Recent studies conducted with planned dry periods: Milk production annually, kg
No significant differences within experiments
dry period (d)
60 30 0
Number of cows 30 30 30
Milk, average for 120 d, lb/d
Primiparous 95 88 71
Multiparous 104 100 92
Recent studies conducted with planned dry periods
Annen at al, 2003
Gulay, 2003
Average for 305 d ME was 71 lb/d for all groups
Period of negative energy balance25% less for 30-day vs 60 d dry periods
Square= no dryTriangle=28 d dryCircle=56 d dry
Annen et al, 2004
Square= no dryTriangle=28 d dryCircle=56 d dry
Shorter dry period: Mammary tissue studies
Little evidence for the loss of epithelial cells No net loss of mammary cells Tissue area occupied by epithelium did not
decline Alveolar structures remained intact The dry period is important for replacement of
aging alveolar cells before the next lactation (Capuco and Akers, 1999) = 3 weeks adequate
Cow health and reproduction
Potentially less metabolic problems with shorter days dry
Return to estrus sooner (ovulated 22 vs 29 d) No difference in udder health All limited data, more research necessary !!!!!!!
Other benefits Dry cow facilities may become less
crowded or more crowded Less movement of cows Cows easier to dry off due to the fact they
are producing less milk? Simplify management as all cows are on
one ration
Shorter dry period?
Most high producing, mature cows qualify Choose cows with second lactation of higher Don’t enroll cows that have a history of short
calving intervals Avoid cows with a high twinning rate Heat stressed cows: heat stress has been
shown to reduce gestation length Exclude cows if you do not know their calving
date
Antibiotic residues a problem?
Dry treating is necessary Dump milk from fresh cows for at least 6
milkings and run a milk antibiotic test after the 6th milking
Keep testing until milk free of antibiotics don’t assume 6 milkings is for all cows
One reason a 40 day dry period may be appropriate
How to feed cows during a short dry period
Anionic salts? 1.58 Mcal of energy /kg of DM 13-14% CP, adequate metabolizable protein Adequate rumen filling capacity, adequate
chewing Need to have minimal change in transition to
lactation diets and contain ingredients from lactating cow diets
Other questions and/or concerns?
Will lactating cow facilities handle 5% more cows? Will the parlor handle 5% more cows? Will you still need two groups of dry cows in order to
manage cows dried off early? Can you manage first calf heifers separately from
mature dry cows? Will there be other drug residue problems? REMEMBER average daily milk yield per cow will
decline, and average DIM will increase BUT total milk shipped will increase
Economics If milk price is $0.12 per lb (US) Total variable expenses while milking is $3.00
per day Total expenses while dry are
$1.25 per day ($3.00 - $1.25)= $1.75 per day $1.75/ $0.12 per lb = 14.6 lb milk per day THERFORE as long as milk income is worth
more than $1.75/d you are better off milking her and they need to milk at least 14.6 lb/d to justify continued milking
Potential benefits to a 40 day dry period
By not feeding a far-off ration, the rumen is less at risk of acidosis from drastic changes in carbohydrate levels
Less group changes may mean less social changes and higher DMI during this critical period
A shorter dry period may mean less total dry cows to house
Less risk of subclinical mastitis, especially due to environmental streptococci
Management strategies Need to have excellent information about
calving dates Inaccurate records may lead to early calvings and
reduced yield Late calvings may suffer from gain of additional
condition
Enough housing to prevent overcrowding Dirty housing Increased mastitis Decreased DMI
Very good management necessary
CONCLUDING REMARKSCONCLUDING REMARKS
May not be for all producers
Still lots more work to be done
Research not really conclusive with regards to benefits to cows and/or producer
Length of the dry period should be continuously evaluated as changes in milk price, replacement availability, cash flow, and plans for the future change
May try 42-45 days initially
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