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