Why a dry period for cows and management tips

The mammary gland of the dairy cow requires a non-lactating (dry) period prior to an impending parturition to optimize milk production in the subsequent lactation. This period is called the dry period, and it includes the time between halting of milk removal (milk stasis) and the subsequent calving. Generally, 50 to 60 days is recommended. If the dry period is less than 40 days, then the milk yield in the next lactation is likely to decrease.

The dry period is necessary to allow the mammary gland to go through a normal period of involution and to ensure that the mammary cell numbers continue to proliferate normally during early lactation. A short or absent dry period greatly reduces the number of secretory cells in the mammary gland.

The amount of milk produced during a cow’s lactation can be influenced by the length of her dry period. Many studies have shown that cows dry for 60 days give approximately 113 kg more milk the following lactation, compared to cows dry fewer than 40 days, which produce around 225 kg less milk the following lactation. Dry periods longer than 60 days show only a moderate decline in milk production compared to those cows dry 60 days. The reason for keeping dry periods close to 60 days  short dry periods do not allow enough time for mammary gland involution while long dry period results in excess body condition.

In field conditions, the dry period of the cow represents one of the most neglected. The early dry period and the close up dry period are times of increased susceptibility to new infections.

During the dry period, the risk of new infection by contagious mastitis pathogens is greatest during the first two weeks. Teat end exposure to environmental pathogens is constant throughout the dry period. 50 – 60% of all new infections during lactation are caused by environmental pathogen exposure during the dry period. Over 50% of clinical coliform mastitis cases occur within the first 70 days of freshening as a result of dry period infection (20% within first week).

As the milk demand is increasing, it has put immense pressure on the dairy farming practices and demands on early lactation cows. The stressful period can have a negative effect on a cow’s health, feed intake, and milk production.

Dairy cows are at a vulnerable state when they’re between lactations. This is why a rest period is required in between, primarily because they will be more prone to nutritional issues at this time. The rest period is an important process in a cow’s lactations because this helps to prevent health problems that may give serious problems to the cow’s milk production and future lactations.

It is important to go through the proper drying-off procedure to prevent the emergence of diseases and infections such as mastitis and intra-mammary infections. It is generally recommended to first withdraw concentrates from the cow’s ration for one to two weeks, and then afterwards to gradually stop milking.

As drying-off goes, when the cow isn’t milked for 18 hours or more, the milk glands will stop producing droplets of milk. This will reduce the size of the udder and will start the cow’s dry period of 60 days. Be reminded that during this period the cow should be placed in clean and dry pens and is separated from the lactating cows.

During the dairy cow’s dry period, we should take care to check for diseases and infections that the cows may develop. Three important things to check would be mastitis prevention, vitamin supplementation, and the cow’s body condition. (blog dated April 21, 2010).

Management factors can help alleviate some of the stress at this time , however, it takes a strong dry period program to make a successful and profitable transition from a dry to lactating cow. Management of the fresh cow also begins during the dry period. It is important to feed dry cows a balanced ration (including vitamins and minerals) and they should not lose body condition during this time. Losing body condition during the dry period can lead to metabolic disorders, such as fatty liver and ketosis, which can reduce milk production in the next lactation.

Vitamin supplementation is probably most vital for cows in late pregnancy, as it needs large amounts of vitamins, particularly vitamins A, D, E and selenium. Vitamin A helps in preventing premature and stillborn calves and retained placenta, while vitamin E and selenium helps to enhance the body’s defenses from infectious agents. A balanced vitamin supplemented diet is needed during the cow’s dry period.

Pregnancy and lactation, reproduction and milk production, takes a considerable toll on the cows. They also have a reduced dry matter intake for the first two months of lactation. This is why the cows must have stored body fat as a source of reserve energy, especially during this period.

Lactating cows usually use about 1 kg of stored fat each day to produce 7 kg of milk. If the cow uses up more than 1 kg, especially in the first 14 days of lactation, ketosis may occur because of the fat that is accumulating in the liver. The interval to the conception will be longer than normal in this case.

The normal procedure to dry off a cow is to withdraw all grain  (concentrate) and reduce the water supply two weeks prior to the start of the dry period. This drastically reduces the milk production during that time. Then milking is halted abruptly about 45 to 50 days before expected date of parturition. Intermittent milking along with a decrease in the energy concentration of the ration can be used as a method to achieve the target yield. Cows should be observed closely for the first two weeks after drying off to ensure that udders are involuting properly. Udders with swollen quarters should be examined for mastitis.

Infusion of the udder with antibiotics can help prevent infections that may occur in early involution. After milking is stopped intra-mammary pressure increases, milk products accumulate in the gland, and further milk secretion is inhibited.

Infusion Procedures:

The teats must be cleaned and sanitized carefully before any infusion. Without proper preparation, organisms present on the teat end may be forced into the udder and result in a severe infection especially if Gram-negative bacteria are introduced.

a. Clean and dry teats.

b. Dip teats in an effective germicidal product. Allow 30 seconds contact time before wiping teats with an individual disposable towel.

c. Thoroughly clean and disinfect each teat end, paying particular care to the teat orifice, by scrubbing with a cotton swab soaked in 70% alcohol. Use a separate piece of cotton for each teat.

d. Prepare teats on the far side of the udder first, followed by teats on the near side. (Teats may be cleaned and infused individually, if necessary.)

e. Treat quarters in reverse order; near side first, far side last.

f. Insert only the tip of the cannula into the teat end and express all of the contents. Do not allow the sterile cannula to touch anything prior to infusion.

g. Do not massage the teats to disperse the product.

h. Dip teats in an effective germicidal product after treatment.

i. Identify treated cows and remove them from the milking herd to prevent antibiotics from entering the milk supply.

Sometimes if the udder becomes extremely congested, it may need to be re-milked. However, this practice stimulates further milk synthesis because intra-mammary pressure is reduced and pituitary hormones (oxytocin and prolactin) are released. Perhaps more importantly re-milking removes the leukocytes from the udder at a time when many are needed to prevent infection. It usually is unnecessary to re-milk if production is reduced below about 22 kg per day before milking is stopped. This is as per US standards, when the average milk per lactation is 10760 kg, which on a 305 days basis would be 35 kg/day. With that said, if the milk production drops to 60%, then milking can be stopped to dry the cow.

Hence it is important to keep in mind the production level at which the cows should be dried off at, which depending on a cow’s production, may result in a dry period longer or shorter than 60 days. The production level for drying off a cow generally is defined as the daily milk yield at which the return from milk is equal to the labor cost for milking plus the cost of additional feed above maintenance and pregnancy levels. Both the current and subsequent lactation periods must be taken into consideration when making this decision.

Summary:

The dry cow period must be of adequate length and should not be a time when cows are left to fend for themselves.

* Maintain 50-60 days dry period for first calf heifers as there is little benefit fpr dry period after first lactation of less than 50 days.

* A 30-40 day dry period after second and later lactations is beneficial to lifetime performance and can be done without any detriment to lifetime yield, if proper measures are taken.

* Dry period of less than 35 days and more than 70 days should ne avoided

Balanced rations should be fed in both the close-up and the far-off dry cow program to help minimize metabolic disorders. Dry matter intake should be stimulated two weeks before calving and during the first month after calving to maximize milk production in these highly stressed cows.

Dry Cow Management Considerations:

* Dry treat all quarters

* Barrier dips/teat sealants

* Mastitis vaccination program

* Nutritional supplementation

* Separate from milking herd

* Clean dry environment

* Quarter SCC at dry off and freshening

Milk production and somatic cell count are inversely related; as somatic cell decreases, milk production will increase.

Amit Sachdev, India Consultant, World Wide Sires, Email: indiawws@gmail.com

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Managing Heat Stress

Heat stress occurs when a dairy cow’s heat load is greater than her capacity to lose heat. Heat stress effects include: increased respiration rate, increased water intake, increased sweating, decrease in dry matter intake, slower rate of feed passage, blood flow to internal organs, milk production and poor reproductive performance. The lower milk production and reproductive performance also causes economic losses to commercial dairy producers.

Reports indicate production losses up to 50 percent, diminished reproductive proficiency and only 10 – 20% inseminations in heat stress cows result in conceptions. In worst-case scenarios, conception could be ZERO.

Effects of heat stress on cattle

1. Cattle sweat only 10% as much as man.

2. Evaporative cooling is needed.

a. Body sprinkling

b. Good air movement

c. Shade

3. Feed intake is reduced by 8% to 12% or more.

4. Volatile fatty acid production in the rumen is decreased.

5. Panting can increase the cow’s maintenance requirement by 20%.

Temperature guide

1. Optimum temperature……………………………. – 4 – +18°C (heat stress starts at 20°C)

2. Decreased feed intake……………………………. 27°C+

3. Reduced performance……………………………. 32°C+

a. Decreased production, 3% to 20% or more

b. Poorer conception, as low as 0%

4. Caution zone…………………………………………38°C and 20% humidity

a. Take steps to ease stress and cool cow

5. Danger zone …………………………………………38°C and 50% humidity

6. Lethal zone …………………………………………..38°C and 80% humidity

High producing animals exhibit more signs of heat stress, because they produce more heat as they eat more to produce higher quantity of milk. and hence must get rid of the heat.

By managing temperature and feeding right the production and conception can be kept at optimal levels

Some key observations in heat stressed animals

a. Rapid Shallow Breathing

b. Profuse Sweating

c. Decrease in Milk Production by 10 percent

d. Reduced feed intake

e. Open mouth breathing and tongue hanging out

f. Rectal temperature up to 103° – 104°F

g. Respiratory rates up to 80 breaths per minute and may be 100 in extreme cases

h. For every 1 kg drop in dry matter intake, loss of production is 2 kg

Step 1: Providing cool water and shade

Providing access to water during heat stress should be the first step. Lactating dairy cattle will typically require between 130 and 170 liters of water per day. Studies have shown that water needs increase 1.2 to 2 times when cows are under heat stress.

In warmer climates the following formula is used to calculate the required tank perimeter: group size x .15 x 2 = tank perimeter in feet.

Water
Requirements for a 650 Kg Lactating Cow
Milk 15OC 25OC 30OC
Production
25 Kg 95 L 102 L 109 L
35 Kg 108 L 115 L 121 L
45 Kg 121 L 127 L 134 L

It is very important that cows have water in a location that is close to shade, since they will not travel great distances for water in a hot environment. Water should be placed away from the milking parlor but in an exit lane from the barn as well as near the feeding location of the cows. Water should be available for cows near their loafing area, either in the shade of trees or artificial shade.

Water also should be clean and cool. As needed, troughs should be cleaned to ensure that algae and other contaminants are not in the water. Water should always be fresh and at approximately ground temperature.

Providing shade is an important factor in combating heat stress in high producing animals. Comfortable cows are happy and produce more milk and are profitable. Shading from direct sunlight is also very important, as this allows cows to rest in a more comfortable environment.

Cows housed in dry-lot or pasture situations should be provided with solid shade. Cows housed with shade yield higher milk and have better conception rates than non-shaded cows.

Shades should be constructed at a height of a least 14 feet with a north-south orientation in an open dairy lot to prevent wet areas from developing under them. There shout be 40-50 sq ft solid shade per cow. In a free stall barn east-west orientation is preferred.

It is also important for cows not to produce a mud-hole in the shaded area where they congregate around the trees. This mud-hole can result in greater mastitis as animals will often lie in the mud after milking and before the sphincter muscle on the end of the teat has tightened up following milking.

Step 2: Evaporative Cooling

To alleviate heat stress in lactating cows provide a more comfortable environment in the holding pen (prior to milk and exit lane). The holding pen is the most stressful location for milking cows during periods of heat stress if it is not shaded and cooled. Reports indicate that proper cooling of the holding pen can pay for itself in two hot summers.

Cool the holding pen area with a combination of shade, air movement and water. When combined with air movement, water can increase cooling ability of the cow. However, adding water in humid or poorly ventilated holding pens or barns can make the situation worse. The water can actually hold the heat in the cow if it does not evaporate from the cow. If cooling is done effectively with fans and water in the holding pen, less cooling is required between
milking.

When cows were cooled in the holding pen, milk production increased 0.75 kg per day during the summer. Low-volume sprinklers and fans can be used to wet cows and speed evaporation of the water off the cows backs. Fans should operate continuously providing a minimum of 1,000 CFM per cow. Fans should be mounted overhead and blow downward at a 30 degree angle. Fans of 36-to 48-inches in diameter are most common. Fans are typically placed side by side spaced 6 to 8 feet apart. The distance between rows of fans is 20 feet for 30 and 36-inch fans and 40 feet for 48-inch fans.

Cooling cows as they exit the parlor provides an additional 15 to 25 minutes of cooling per milking. Typically three to four nozzles are installed in the exit lane, with a delivery of approximately 30 liters of water per minute at 35 to 40 pounds per square inch (PSI). The nozzles are turned on and off with an electric eye or wand switch as the cow passes under the nozzles.

If properly installed, sprinkler should wet the top and sides of the cow, the udder will remain dry, the water will not interfere with post dipping.

Step 3: Proper Feeding

To decrease heat stress, increase the density of the ration. High quality forages should be available to the animal if possible. This will reduce the heat produced in digesting and assimilating feed. These forages may include summer annuals or a high quality perennial. Silage, pasture and hay are acceptable. The primary reason that cows decrease in milk production during hot weather is that the cows eat less. Since cows will be consuming less as temperatures increase, increasing the energy density of the diet can in part compensate for the decrease in dry matter intake.

Temperature in
deg C
Required DMI Actual DMI Milk Production
20 18.1 Kg 18.1 Kg 26.9 Kg
25 18.3 Kg 17.6 Kg 24.9 Kg
30 18.9 Kg 16.9 Kg 22.9 Kg
35 19.4 Kg 16.6 Kg 18.0 Kg

Some reports available indicate that the neutral detergent fiber (NDF) level should be at least 28% to 30% in the total ration dry matter (TRDM) to maintain production and a reasonably normal fat test. If NDF level cannot be estimated, make certain that acid detergent fiber level is at least 18% to 20% of the total ration dry matter.

Extra water may be added to the TMR, silage, or haylage if dry matter intake (DMI) drops seriously. This will increase DMI appreciably. Increase levels of certain minerals like Potassium, Magnesium and Sodium for lactating cows to compensate for higher losses from the body during hot, humid weather.

Provide most of the ration during the cooler periods of the day to minimize heat production when temperatures are higher:

a. Early morning hours from 4:00 to 6:00 a.m.

b. Evening hours from 9:00 to 11:00 p.m.

c. Keep smaller amounts of feed available during daytime hours

Feed ensiled items more frequently to compensate for shorter bunk life during hot weather to prevent heating and improve feed intake.

a. Remove from silos at feeding time, not ahead

b. Feed more frequently if heating or appreciable drop in intake occurs

Feed a higher fat ration (up to 5% to 7% of the total ration dry matter from all sources) if a reasonable dry matter intake (90%+ of usual) cannot be maintained.

Use unprotected fat sources (i.e. oilseeds) to meet the 5% fat level. Protected fat sources should be used to meet fat levels between 5% to 7% in the total ration dry matter.

Summary

Keeping lactating cows cool can provide a good return on your investment as it makes cows more comfortable, thereby making them more productive. Shade and cool water should be available to cows and heifers at all times. Cooling devices should also be installed in the holding pen and feeding area if possible.

The ration should be properly balanced, and generally the energy density should be increased in the summer to help compensate for decreased dry matter intake of the cow

1. Supply adequate cool and fresh water.

2. Provide shade in the housing areas (both dry and lactating cows) and holding pen.

3. Reduce walking distance to the parlor.

4. Reduce time in the holding pen.

5. Improve holding pen ventilation and freestall ventilation.

6. Add holding pen cooling and exit lane cooling.

7. Cool close-up cows (those within three weeks of calving).

8. Cool fresh cow and early-lactation cow housing.

9. Cool mid and late lactation cow housing.

Amit Sachdev, India Consultant, World Wide Sires, E mail: indiawws@gmail.com

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Reduce GHG emissions from the dairy industry – increase efficiency of production; A new approach – when to introduce fresh calved dairy heifers

Reduce GHG emissions from the dairy industry – increase efficiency of production
A new report from Foreign Agricultural Office (FAO), suggests that of the total global anthropogenic  (caused by humans) green house emissions (GHG), the dairy sector accounts for around four per cent of the emissions. A report in 2006 from FAO has stated that 18 percent of the emissions are from livestock sector.
The 4 percent emissions include all the emissions associated with the production, processing and transportation of milk products as well as emissions related to meat produced from animals originating from the dairy system.

Considering just global milk production, processing and transportation and excluding meat production, the sector contributes 2.7 per cent of global anthropogenic GHG emissions.

In 2007, the dairy sector emitted 1,969 MMT of carbon dioxide (CO2) equivalent, of which 1,328 MMT were attributed to milk, 151 MMT attributed to meat from culled dairy animals, and 490 MMT from calves from the dairy sector that were raised for meat. The report does not include emissions from Buffaloes. The CO2 equivalent emission is a standard measurement for comparing emissions of different GHGs.

The global average of GHG emissions per kilogram of milk and related milk products is estimated at 2.4 kg CO2 equivalent.

Methane contributes most to the global warming impact of milk, accounting for about 52 per cent of the GHG emissions in both developing and developed countries.

Methane from enteric (microbial) fermentation represents 20% and manure management 7% of the total CH4 emitted. Ruminants (beef, dairy, goats, and sheep) are the main contributors to CH4 production.
The ruminant animal is unique because of its four stomach compartments: reticulum, rumen, omasum and abomasum. The rumen is a large, hollow muscular organ where microbial fermentation occurs. It can hold 150 to 230 liters of material and an estimated 150 billion microorganisms per teaspoon are present in its contents. The function of the rumen as a fermentation vat and the presence of certain bacteria promote the development of gases. These gases are found in the upper part of the rumen with CO2 and CH4 making up the largest portion, 65.5% and 26.8% respectively.
Considering a fact that the world has 1300 million dairy cattle, each animal would contribute 1.02 MT of CO2. Based on the above, considering the numbers for 2006 as the Dept of AH, India had 8.2 million crossbred animals in production and 28.37 million non descript animals in production and the milk production was 19.244 MMT and 20.415 MMT respectively. The average milk production was 1.087 T/animal/year. The GHG emission would have been 37.37 MMT. As the a report from IFPRI, the estimated cow population in India would be 38.317 million and the production of milk attributed to cows would be about 41% of the total milk production, approximately 44.485 MMT, with an average milk production of 1.16 tons/animal/lactation. Based on the above, Indian cows contribute 39.09 MMT of CO2 equivalents, which in case of US would be only 10.2 MMT, based on the fact that the total population of cows in US is only 10 Million, with an average production of 10 tons/animal/year.
It is important to understand that and identify opportunities where in interventions can be made to reduce the emissions. 
As per a report from Penn State University, research has been conducted in Canada, Australia, Europe and the US on strategies to reduce methane emissions from dairy. The main focus has been on nutritional strategies, including feed higher efficiency feeds, good quality forages etc. Increasing the efficiency of production in which animals use nu
trients efficiently to produce milk can result in reduced CH
4 emissions. This can be accomplished by feeding high quality, highly digestible forages and grains including balanced rations.
Relatively new mitigation options have been considered and include the addition of such additives as probiotics, acetogens, bacteriocins, organic acids, and plant extracts (i.e. condensed tannins). For the long-term approach though genetic selection of cows that have improved feed efficiency (produce more milk/kg of feed consumed) is the only possibility
A new approach – when to introduce fresh calved dairy heifers
An important decision so as the older, resident animals are not aggressive and harm the new entrants in the family. A Report from Queens University, cites that the newly calved heifers should be introduced in the main herd after the second milking (afternoon milking) only. An early morning release may have a negative impact on fresh animals.
Heifers normally have a low social status and could be subjected to increased bullying by older resident females. This could be stressful to the animals and could affect the performance. It has been found that cows are naturally less socially active in the evening and hence less aggressive.
Also it is important that the fresh heifers are introduced 24-36 hours after the calving. 

Amit Sachdev
India Consultant
World Wide Sires
E mail: indiawws@gmail.com

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Mastitis prevention and control – important for a profitable dairy operation

Mastitis is an inflammation of the mammary gland and the presence of an intra-mammary infection (IMI) is not required for mastitis to exist. However, the vast majority of mastitis cases are due to an intra-mammary infection caused by microorganisms. Over 100 different microorganisms have been shown to cause IMI but most of the economic losses are associated with species of staphylococci, streptococci, and the coli-form bacteria.


Major Mastitis-Causing Pathogens and sources of infection
Pathogen
Source and Control
Staphylococcus aureus
Lives in the udder or on wounds, milkers hands, Transferred to the teat by milking machine or milking practices. Can be controlled by hygiene, milking procedure and culling. Often resistant to treatment.
Streptococcus agalactiae
Lives in the udder and spreads from cow to cow, usually by poor milking practices. Can be controlled by strict hygiene and dry cow therapy. Can be treated successfully during lactation.
Environmental Streptococci
(Str. uberis or Str. dysgalactiae
Lives in the environment and can be controlled by good sanitation and hygiene, clean stall and environment management. Responds to lactation and dry cow therapy.
Coliform
(E coli, Klebsiella)
Lives in manure, or dirty, wet and muddy areas; polluted water, dirty milking equipment. An environmental problem, which can be tackled by good sanitation and hygiene. Infections can occur between milkings and may also be caused by poor milking practices.


The infectious agents can be divided into two main groups – contagious and environmental including skin flora. The contagious agents spread from cow to cow primarily during milking while the environmentals infect cows mostly from their growth locations in the bedding and surrounding areas.
Despite considerable research on bovine mastitis the disease still remains an economically relevant problem to the dairy industry. Economic losses are estimated to be approximately $250 per cow per year in the U.S, which includes milk lost & discarded, veterinary costs, labor costs etc. Additional costs incurred by the processing industry in terms of reduced cheese yields, and the manufacture of products with reduced shelf life and consumer acceptance, which are normally not taken into account.
Mastitis is the most expensive disease in dairy cattle and good mastitis control program will enhance the profits on the farm. Farmers often think that a cow with clinical mastitis is the problem, and do not realize the full impact of mastitis on the herd. For every one cow that has clinical mastitis, studies have shown there will be 15 to 40 more cows in the herd with subclinical mastitis – and this often goes undetected. 
If the Somatic Cell Count (SCC) is less than 200,000 cells/ml, then there is a likely hood that the problem does not exist, but the farmer still needs to be aware of mastitis and continue to implement practices that will keep mastitis out of the herd.  Herds that have a count of more than 300,000 cells/ml are considered to be problem herds and farmers should implement mastitis control measures. A herd where more than 3 cows per 100 cows show clinical mastitis over a month’s time has a costly mastitis problem because of significant lost milk production and reduced economic returns. Subclinical mastitis infections may cause permanent destruction of milk secretory cells which permanently lower milk producing ability.
Contagious infections are caused by S. aureus, Str. agalactiae, or mycoplasma and are usually spread from infected to non-infected cows during milking. S. aureus organisms colonize abnormal teat ends or teat lesions. Milker’s hands, wash cloths, teat cup liners, and flies are ways in which the infection can be spread from cow to cow. The organisms penetrate the teat canal during milking. Irregular vacuum fluctuations impact milk droplets and bacteria against the teat end with sufficient force to cause teat canal penetration and possible development of new infection
The first step in a mastitis control program thus is to use proper milking Hygiene. This means the teats should be clean & dry when the milk is harvested. Individual towels should be used for each cow so as not to transfer bacteria or microorganisms from one cow to another. Proper cow preparation is a very important step in preventing mastitis causing microorganisms from entering the teat end.
Milk with clean hands and wear sterile gloves if needed.  Pre-dip if allowed and necessary and allow 30 seconds contact time. Dry teats thoroughly, using single service paper or cloth towels. Examine fore-milk for clinical mastitis (flakes, clots, watery milk).  Wash teats with only as much water as necessary to get clean; using paper or cloth towels to scrub teats when dirty. (This step may be eliminated if teats are reasonably clean).
Milking machines can serve as a vector for transferring mastitis organisms from one cow to another, or they may propel droplets of milk back into the teat end, contributing to mastitis. Ensure milking machines are well maintained and the equipment is functioning correctly. Be sure to apply the machines quickly and remove the machines only when the vacuum has been shut off. Listen to the milking machine for air leaks that can cause droplets of milk to be impacted back into the udder of the cow. Avoid over-milking.
Dip teats after milking (iodine solution) covering at least the bottom half of teat. This will kill the microorganisms that are on the teat and aid in closing the sphincter muscle. If environmental mastitis is prevalent in the herd, pre dipping (dipping the teats before milking) and removing the dip completely can assist in the reduction of mastitis. Avoid allowing the dip to become contaminated with manure or other bacteria laden material. Use dip cups that have a small reservoir that will contain enough dip to treat one cow at a time.
Until the sphincter recovers and closes tightly (30-45 minutes), the mammary gland is at high risk for new infections if the teat end is place on bedding or in manure. By providing fresh feed and water after milking, the cows will remain standing to eat while the sphincter closes thus reducing the risk of infection.
The treatment of every quarter of every cow with a specially formulated long lasting antibiotic is essential for providing the cow with protection during the dry period. Most new cases of mastitis occur in the cow during the first two weeks after drying off and the two weeks prior to calving. At these times the infection will go unnoticed and will increase the number of cows that have mastitis early in lactation. This step is essential in reducing the number of new cases in the herd, and is the only way to effectively treat and eliminate contagious mastitis from the herd.
Cows infected with contagious mastitis must either be culled, segregated from the milking herd and milked last, milked with separate milking units, or teat cup liners must be rinsed and sanitized after milking infected cows (backflushed). Treated cows should be milked last to avoid antibiotic contamination of the bulk tank, even when a special milking unit is used.
It is very important to make a conscious effort by the persons milking the cows to detect all mastitis cases, and treat them promptly. Only approved and recommended mastitis treatments should be used to treat cows. It is important the full treatment regime be followed. It is also important that withdrawal times be observed to insure antibiotics are not permitted to contaminate the milk being sold to processors. Milk from treated cows, or cows with mastitis should not be fed to heifer calves.
Cows that do not respond favorably to treatment, or that continue to become infected should be culled from the herd. The continued presence of these cows in the herd can contribute to the infection of other cows in the herd. Cows that do not respond to treatment or continue to become infected are not economic and will cost the dairyman money. When making the decision to cull a cow, make sure the withdrawal time for the antibiotic is observed. 
Developing and following good bio-security system takes time and planning, but the cost to the farm enterprise for not having these systems can be considerable. It is also important to remember that developing bio-security plans decreases the risk of introducing health problems to the herd, but there is no guarantee that it will completely prevent the introduction of disease to the herd. Monitoring bulk tank SCC and bacteria, individual cow SCC, and clinical mastitis rates are ongoing tasks and essential for maintaining high levels of herd health and milk quality.

Information courtesy – Mr.Lindell Whitelock, Consultant, WWS; Mastitis Basics – Dr.John Kirk; Virginia Cooperative Extension Publication (Mastitis pathogen and control) and others.

Amit Sachdev
India Consultant
World Wide Sires
email: indiawws@gmail.com

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ESTRUS DETECTION – KEY TO HIGH PREGNANCY RATE

In the last two blog posts I have provided details on handling semen tanks and later handling frozen semen for best results. I hope the information was of value. In the new blog post I will try to provide the information on heat detection. The article below is has been contributed by Mr.Lindell Whitelock, Consultant to World Wide Sires, USA and also information has been taken from Estrus Detection Guide, South Dakota University.

Success in conception is dependent on insemination timing, which is dependent upon a good heat detection program. A continued education program for the workforce is important. A successful heat detection program and subsequent proper timing of insemination will pay dividends in increasing reproductive efficiency. If a cow shows estrus in the morning, it must be inseminated the same day, next day would be too late. If estrus is detected in the afternoon, must plan to inseminate morning of next day at the latest. Plan inseminations in the morning – evening (AM-PM) rule and inseminate the animals within the 5-12 hr period of estrus cycle.
Estrus detection is the key to improving reproduction performance in the dairy herd. It is important not only to determine which cows are in “heat” but also to determine when the cow actually came into standing heat so the cow can be inseminated at a time when the cow is most likely to conceive.
The standing estrus (the sexually receptive period) is a result of a series of hormonal changes that occur at the end of each estrous cycle. Standing estrus is when a cow/heifer stands to be mounted by a bull or a female. In a normally cycling animal, standing estrus will occur approximately every 21 days, but this can range from 17 to 24 days.
Cows enter standing estrus gradually; secondary signs that an animal is getting close to standing estrus will progress until the animal stands to be mounted. None of the secondary signs alone is a positive determination of standing estrus. Standing to be mounted by a bull or another cow/heifer is the only conclusive sign that an animal is in standing estrus and ready to be inseminated.
The period of standing estrus usually lasts about 15 hours but can range from less than 6 hours to close to 24 hours. To maximize detection of standing estrus, it is extremely important to monitor cows/heifers as closely as possible—early in the morning and late at night as well as during the middle of the day.
A report suggests that continuous observation of over 500 animals in three separate studies indicated that 55.9% of cows initiated standing estrus from 6 p.m. to 6 a.m. When cows were checked for standing estrus every 6 hours (6 a.m., noon, 6 p.m., and midnight), the estrous detection rate increased by 19% compared to checking at 6 a.m. and 6 p.m. alone. Checking for standing estrus at 6 a.m., noon, and 6 p.m. increased the estrous detection rate by 10% compared to detecting estrus at 6 a.m. and 6 p.m. alone.
Unfortunately on many farms the estrus detection rate is very low, many times at less than 40%. A good estrus detection program should result in an estrus detection rate of 70% to 80%. Developing a good estrus detection program should be a priority if a farm is experiencing a low pregnancy rates.
Detecting standing estrus (“heat detection” or “detecting standing heat”) is simply looking for the changes in animal behavior that are associated with a cow/heifer standing to be mounted by a bull or another female. Detecting animals in standing estrus is critical to the success of any artificial insemination program. Animals not in estrus around the time of insemination have little chance of becoming pregnant.
The development of a successful estrus detection program involves the following steps. 

Development of a Standard Operating Procedure (SOP): The SOP should address many issues. The SOP should identify the person or persons who are responsible for the task. It should set forth the times when and where the cows are to be observed. It should also specify where the information will be recorded and who gets the information. It should also specify who gets that information and when.

Trained Personnel: Ensure the persons who are assigned the task of estrus detection are trained and confident in identifying the cows. To assist the people who are responsible for identifying the cows, prepare alert lists, consider using estrus detection aids, and even though a cow has been bred, keep watching until a pregnancy is confirmed. Ensure observed heats are recorded and the information is used to make breeding decisions.

Group all the open cows together: By locating all of the cows in one group, the cows are more likely to show behavioral signs of estrus and the observation of the cows can be conducted in a more efficient manner. Ensure the area where the cows are kept is comfortable and the floor surface provides for good footing for the cows. Do not overstock the pens; cows need room to move around if they are to exhibit signs of estrus.
Sore feet: Cows with sore feet do not mount other cows, and they do not allow othe cows to mount them. A cow with sore feet can be identified by an arch in her back. Cows with healthy feet walk with a straight back, so if several cows have even a slight arch in their back, the likelyhood of them showing physical signs of estrus are very low. Minimize sore feet  to improve estrus detection.

Observe cows every 6 to 8 hours: The observation, unless using a “Chalk & Breed” program should not be done at milking time or when cows have been fed. Multiple times observation will not only find more cows in estrus, but will also assist in being able to determine when the first standing heat occurred. This will also result in higher conception rates. ensure the data is recorded and reported so the cow is inseminated.

 

Estrus Detection Aids: Estrus detection aids such as pedometers may be used to assist in the identification of cows that are in estrus. If aids are used, then it is important to observe the cow as well. Look for secondary signs of estrus that would indicate the cow is actually in heat. Estrus detection aids can only help, but they do not replace actual observation of the cow.In every herd there will be problem cows. Cows that are not observed in estrus may require other actions. A program of using an estrus synchronization or hormonal program should be considered for the herd. A protocol should be developed to determine what the voluntary waiting period will be and when synchronization programs would be implemented. There are several synchronization protocols that can be used. 


Problem Cows: In every herd there will be problem cows. Cows that are not observed in estrus may require other actions. A program of using an estrus synchronization or hormonal program should be considered for the herd. A protocol should be developed to determine what the voluntary waiting period will be and when synchronization programs would be implemented. There are several synchronization protocols that can be used.


Key People:  A successful estrus detection program depends on people. The people must be trained, must understand the importance of their task and must communicate their findings. Estrus detection is the key to improved reproduction efficiency and that largely depends on people.


Amit Sachdev
India Consultant
World Wide Sires, USA
Email: indiawws@gmail.com


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