ANFS251 Lecture 23: Dairy Cattle - Part 1
28 Feb 2018
School
Department
Course
Professor
All metabolic diseases, all associated with a change in diet
•
Acidosis
Rumen acidosis is a metabolic disease of cattle. Acidosis is said to occur
when the pH of the rumen falls less than 5.5. The change in acidity
changes the rumen flora, with acid-producing bacteria taking over. They
produce more acid, making the acidosis worse. The increased acid is then
absorbed through the rumen wall, causing metabolic acidosis, which in
severe cases can lead to shock and death
○
Cause: the primary cause of acidosis is feeding a high level of rapidly
digestible carbohydrate. In dairy cattle, acidosis is seen as a result of
feeding increased concentrates compared to forage
○
Symptoms: reduced feed intake, poor body condition and weight loss,
lethargy
○
•
Milk fever
Milk fever is a disorder mainly of dairy cows close to calving. It is a
metabolic disease caused by a low blood calcium level (hypocalcemia)
○
Losses are due to deaths (about 1 in 20 affected cows dies), a reduction in
the productive lifespan of each affected cow of about 3 years, and
reduction in milk production following each milk fever episode, as well as
costs of prevention and treatment
○
Symptoms: In typical cases cows show some initial excitement or agitation
and tremor in muscles of the head and limbs. Then they stagger and go
down to a "sitting" position, often with a 'kink' in her neck, and finally lie
flat on their side before circulatory collapse, coma and death
○
Causes: about 80% of cases occur within one day of calving because milk
and colostrum production drain calcium (and other substances) from the
blood, and some cows are unable to replace the calcium quickly enough.
High producers are more susceptible because the fall in their blood
calcium level is greater
○
Treatment: treated with oral calcium gel or boluses, or calcium gluconate
under their skin
○
•
Displaced abomasum
The abomasum (or true stomach) normally lies on the floor of the
abdomen, but can become filled with gas and rise to the top of the
abdomen, when it is said to be 'displaced'
○
Cause: the majority of cases occur soon after calving. During pregnancy
the uterus displaces the abomasum, so that after calving the abomasum
has to move back to its normal position, increasing the risk of
displacement
○
Symptoms: loss of appetite, drop in milk yield, reduced rumination, mild
diarrhea
○
Treatment: treatment requires replacing the abomasum in its normal
position. Preferably, the veterinarian also prevents recurrence by tackling
the abomasum to the body wall. Surgery can be preformed, however it
isn't always necessary. Often the abomasum can be returned to its usual
place by casting and rolling the animal onto its back, permitting the
abomasum to "float" back to its normal position
○
Prevention:
Prevention should be aimed at ensuring dry matter intake is
maintained in early lactation
§
Ensure cattle are not too fat at calving
§
Feed high quality feeds, with good quality forage
§
Feeding a total mixed ration as opposed to concentrates
§
Minimize changes between late dry and early lactation ration
§
It is likely that a farm with numerous DA problems is feeding the
late dry and/or early lactation cows
§
○
•
Ketosis
Ketosis is a metabolic disorder that occurs in cattle when energy demands
(ex high milk production) exceed energy intake and result in a negative
energy balance
○
Cause: when large amounts of body fat are utilized as an energy source to
support production, fat is sometimes mobilized faster than the liver can
properly metabolize it. If this situation occurs, ketone production exceeds
ketone utilization by the cow, and ketosis results. In the dairy cow, the
mismatch between input and output usually occurs in the first few weeks
of lactation, because the cow is not able to eat enough to match the
energy lost in the milk.
○
Symptoms: reduced milk yield, weight loss, reduced appetite, acetone
(pear drop) smell of breath/ or milk, some develop nervous signs including
excess salivation, licking, aggression etc
○
Treatment: The initial aim of treatment is to restore the lack of glucose in
the body. A quick-acting glucose supplement is required immediately.
Follow-up treatment is aimed at providing a long term supply of glucose.
○
The body condition of the dairy cow is important at calving. Cows should
be on a rising plane of nutrition up to calving with the aim to calve in good
condition. After calving, the cow has the potential to reach maximum
efficiency in milk production, but feed requirements for high production
are often greater than the voluntary intake of pasture can provide.
Therefore an energy supplement is required and there is evidence that
this will improve production and reproductive performance, and decrease
the risk of ketosis.
○
•
Dairy cows eat a lot!
Need to consume a lot of feed to achieve levels of production
Some cows produce more than 34,000 lbs of milk annually (over
4,200 gallons)
§
○
Nutrient needs vary tremendously throughout the lactation and dry
period cycle
○
At peak production, the dairy cow may require 3-10x as much protein as
energy as she required during late gestation
○
Further complicated by cows appetite - usually lags behind their nutrient
requirements
○
•
The cycle•
Relationships between milk production, dry matter intake and body
weight changes typically observed during normal
lactation/gestation cycle
§
Milk production increases rapidly and reaches peak production 6-9 weeks
after calving
○
Appetite lags behind production
Maximum daily dry matter intake occurs 12-15 weeks postpartum
§
Cows are in negative energy balance for 8-10 weeks
§
Makes up these nutrient deficits by borrowing from her body stores
§
○
Often lose 90-135 kg of body weight during early lactation
Supports 700-900 kg of milk production
§
○
After optimal dry matter intake is achieved
Intake follows production requirements and decreases as
production decreases
§
Tends to consume more than she needs during later lactation
Allows her to regain body weight lost in early lactation□
§
○
Should regain most of lost body weight during late lactation for optimal
energetic efficiency
○
Weight gain during the dry period accounted for by fetal growth
○
•
Bovine somatotropin
For cows injected with bovine somatotropin (bST), there may be a second
increase in production within a few days of initial injection
May again experience a short time of negative energy balance
§
○
Production typically increases about 10% as a result of bST injections
Dry matter intake needs to increase 2%-3% to supply nutrients
needed for increased production
§
○
Negative effects of bST?
FDA says bST is safest animal drug they ever produced. But causes
more consumer uproar than any others. Doesn’t matter if cow gets
bST. FDA says it is so safe because there are steroid hormones and
protein hormones. All negative media is from steroid hormones, but
average consumer doesn’t differentiate between the two. bST is a
protein and is specific to cows - only makes cows grow. Cows
naturally secrete their own growth hormone and it is immediately
digested by human stomachs and is biologically inactive. It doesn’t
work in humans either way! Concerned it would increase level of
milk production so much that it would lead to higher levels of
mastitis in the cow, leading to higher antibiotics in cow, leading to
higher chance of antibiotics in milk consumed by humans. Never
found. No difference in milk from treated and untreated cows. All
milk contains bST
§
○
•
Phased feeding
The lactation and gestation cycle can be divided into five phases based on
nutritional considerations:
Phase 1 - the first 10 weeks of lactation, when peak production
occurs, and body stores are used to make up for nutrient deficits
§
Phase 2 - about 10 weeks postpartum for most cows, continuing for
10-20 weeks. Maximum dry matter intake, and intake is in balance
with requirements.
§
Phase 3 - intake exceeds nutrient requirements for production,
restoring body reserves
§
Phase 4 - period for any final regain of body weight, and involution
followed by regeneration of secretory tissue in the udder for the
next lactation
Dry period□
§
Phase 5 - the last 1-3 weeks pre-partum
Dry period□
Transition period
Nutritionists tart increasing grain intake to prepare
rumen for increased nutritional intake that will follow
after cow gives birth
®
□
§
○
•
Dry Period
Need a short dry period as rest while preparing for the next lactation
Optimum dry period is 6-8 weeks
§
Dry periods shorter than 40 days do not allow enough time for
udder regeneration, which may cause a decrease in production
during the next lactation
§
○
Dry period - regenerate new secretory tissue and replace lost body
condition
Changes occur in the udder during the dry period:
Active involution; steady-state involution□
Lactogenesis plus colostrogenesis□
§
○
Involution
Active involution
Completed by 30 days into the dry period□
Milk-secreting tissue is reabsorbed□
§
Second stage, steady-state involution
Can exist indefinitely, and the mammary gland remains in a
collapsed state
□
§
Third stage, Lactogenesis plus colostrogenesis
Begins 15-20 days pre-partum□
Involves onset of lactation and the secretion of colostrum□
§
○
Dry-cow feeding emphasizes maintaining body condition
USDA research demonstrated that cows convert feed energy to
body tissue more efficiently in late lactation than during the dry
period
§
If still thin at drying off, need to replenish body stores as well as
provide for fetal growth
§
○
•
Body condition at calving
Body condition score of 3.5 at calving is ideal for high milk yield, high fat
test in milk, and reproductive performance
On a scale of 1-5
1 being very thin and 5 being excessively fat□
§
○
•
Dry-cow rations
Dry cow's nutrient requirements can often be met with only forages
Legume-grass hay and corn silage combination needs only vitamins
and a small amount of P
§
Dry-cow ration can be simple but should include the following
considerations:
Minimum of 1% of body weight as long-stem, dry forage
Preferably grass-hay
®
□
Free-choice feeding of corn silage should be avoid
Leads to excessive energy intake and increases
likelihood of displaced abomasum and fat cow
syndrome
®
□
Grain should be limited to energy and protein needs□
§
○
•
Fat cows
Consuming excess energy from grains and/or corn silage likely to develop
a disorder called fat cow syndrome
High blood lipid levels and fatty livers
§
More likely to have calving difficulties, displaced abomasums,
ketosis, and other health problems
§
○
Cows fed hay and/or haylage are less likely to have problems than cows
receiving free-choice corn silage
Limit corn silage for dry cows to 9.5-11 kg/day
Plus a protein and ca-P support□
§
○
•
More on bred heifers
Nutrient requirements of bred heifers during late gestation are slightly
greater than of dry cows
Bred heifers will likely need some grain along with forages during
the last 3-4 months of gestation (still growing)
§
Good-quality forages can provide all the nutrient needs
§
If forages are not of good quality or if heifers are exposed to severe
weather conditions:
Additional grain may be needed to maintain optimal growth
(not fat)
□
§
Should be in c]good condition but not fat at calving
Usually fed in groups of similar age or size□
§
○
•
Transition period (phase 5)
In the last weeks before parturition:
Aimed at adapting rumen microflora to higher-energy diets needed
postpartum
§
Adjustment often achieved by including small amounts of
ingredients of the lactating ration
Gradually increases concentrates□
This approach often called "steaming up:"□
Minimize the chances for milk fever and ketosis during
lactation
□
§
○
Most cows experience a sharp decrease in total dry matter intake 24-48
hours before calving
Stabilizing the rumen is important to avoid displaced abomasum,
acidosis, and off-feed
§
○
•
Following calving objectives:
Parturition until peak milk production is period when appetite lags behind
nutritional requirements (refer to graph) so peak milk production (phase
1) is negative nutrient balance period
Increase feed intake as rapidly as possible, but not to introduce
ration change so rapidly as to cause digestive upsets and off-feed
1.
Once the stress of calving has passed, concentrate intake can
gradually increase 0.5-0.7 kg/day
2.
If total mixed rations are fed, this equates to a forage-to-
concentrate ratio of 55:45 or 50:50
3.
○
•
Peak milk production
Forage portion of the diet not be less than 45% of dry matter
Successful phase 1 feeding:
Maximizes peak milk yield□
Utilizes some body weight as an energy source□
Minimizes ketosis□
Returns cows to a positive energy balance by 8-10 weeks
postpartum
□
§
○
Cows can compensate for much of their deficit in energy intake
Borrow remaining needed energy from body fat
§
Cannot borrow very much protein so protein must be supplied in
the diet
§
Early lactation cows will benefit from rumen bypass (escape)
proteins
Allows protein to bypass microbes in rumen and proceed
directly to abomasum where the cow can derive the benefits
from dietary protein
□
§
○
Non-protein nitrogen (NPN) supplements will not be efficiently used by
these cows
○
•
Peak milk production: acidosis
High starch, lower fiber diets are more apt to cause acidosis, digestive
upsets, and milk fat depression
Nonstructural carbohydrates (starches and sugars) should be
limited to 30-40% of the diet dry matter to avoid acidosis and other
metabolic problems
§
○
Feeds such as distiller's grains can replace a sizable amount of high starch
feeds while providing more energy and decreasing rumen acidosis
○
•
Peak milk production
Supplemental dietary fat
May allow increased energy density and adequate fiber intake
§
○
At least 2.25 kg of dry hay in the daily ration helps to maintain normal
rumination, especially during early lactation
Long stem is preferred over chopped hay
§
○
•
Maximum dry matter intake
Should be achieved as early in lactation as possible
○
Conception rates are greater for cows in positive energy balance
Cows are usually being bred during this phase in lactation
§
○
Body weights should stabilize, and weight gains should actually start
occurring during this phase
○
Maximum dry matter intake will reach 3.5-4.5% of body weight
○
Dry matter intakes are usually higher for higher producing cows
Not unusual for some cows to consume for than 5% of their body
weight
§
○
•
Sum it up!
We manage dairy cows on an annual gestation-lactation cycle
○
We can include body weight changes and dry matter intake and compare
them to milk production in the different phases of the cycle
○
The result is 5 distinct feeding phases
○
And during those phases we balance body weight changes with the
balance between concentrates and forages in the ration to maintain milk
production and healthy gut flora
○
•
Dairy Cattle
Thursday, April 27, 2017
9:55 AM
All metabolic diseases, all associated with a change in diet•
Acidosis
Rumen acidosis is a metabolic disease of cattle. Acidosis is said to occur
when the pH of the rumen falls less than 5.5. The change in acidity
changes the rumen flora, with acid-producing bacteria taking over. They
produce more acid, making the acidosis worse. The increased acid is then
absorbed through the rumen wall, causing metabolic acidosis, which in
severe cases can lead to shock and death
○
Cause: the primary cause of acidosis is feeding a high level of rapidly
digestible carbohydrate. In dairy cattle, acidosis is seen as a result of
feeding increased concentrates compared to forage
○
Symptoms: reduced feed intake, poor body condition and weight loss,
lethargy
○
•
Milk fever
Milk fever is a disorder mainly of dairy cows close to calving. It is a
metabolic disease caused by a low blood calcium level (hypocalcemia)
○
Losses are due to deaths (about 1 in 20 affected cows dies), a reduction in
the productive lifespan of each affected cow of about 3 years, and
reduction in milk production following each milk fever episode, as well as
costs of prevention and treatment
○
Symptoms: In typical cases cows show some initial excitement or agitation
and tremor in muscles of the head and limbs. Then they stagger and go
down to a "sitting" position, often with a 'kink' in her neck, and finally lie
flat on their side before circulatory collapse, coma and death
○
Causes: about 80% of cases occur within one day of calving because milk
and colostrum production drain calcium (and other substances) from the
blood, and some cows are unable to replace the calcium quickly enough.
High producers are more susceptible because the fall in their blood
calcium level is greater
○
Treatment: treated with oral calcium gel or boluses, or calcium gluconate
under their skin
○
•
Displaced abomasum
The abomasum (or true stomach) normally lies on the floor of the
abdomen, but can become filled with gas and rise to the top of the
abdomen, when it is said to be 'displaced'
○
Cause: the majority of cases occur soon after calving. During pregnancy
the uterus displaces the abomasum, so that after calving the abomasum
has to move back to its normal position, increasing the risk of
displacement
○
Symptoms: loss of appetite, drop in milk yield, reduced rumination, mild
diarrhea
○
Treatment: treatment requires replacing the abomasum in its normal
position. Preferably, the veterinarian also prevents recurrence by tackling
the abomasum to the body wall. Surgery can be preformed, however it
isn't always necessary. Often the abomasum can be returned to its usual
place by casting and rolling the animal onto its back, permitting the
abomasum to "float" back to its normal position
○
Prevention:
Prevention should be aimed at ensuring dry matter intake is
maintained in early lactation
§
Ensure cattle are not too fat at calving
§
Feed high quality feeds, with good quality forage
§
Feeding a total mixed ration as opposed to concentrates
§
Minimize changes between late dry and early lactation ration
§
It is likely that a farm with numerous DA problems is feeding the
late dry and/or early lactation cows
§
○
•
Ketosis
Ketosis is a metabolic disorder that occurs in cattle when energy demands
(ex high milk production) exceed energy intake and result in a negative
energy balance
○
Cause: when large amounts of body fat are utilized as an energy source to
support production, fat is sometimes mobilized faster than the liver can
properly metabolize it. If this situation occurs, ketone production exceeds
ketone utilization by the cow, and ketosis results. In the dairy cow, the
mismatch between input and output usually occurs in the first few weeks
of lactation, because the cow is not able to eat enough to match the
energy lost in the milk.
○
Symptoms: reduced milk yield, weight loss, reduced appetite, acetone
(pear drop) smell of breath/ or milk, some develop nervous signs including
excess salivation, licking, aggression etc
○
Treatment: The initial aim of treatment is to restore the lack of glucose in
the body. A quick-acting glucose supplement is required immediately.
Follow-up treatment is aimed at providing a long term supply of glucose.
○
The body condition of the dairy cow is important at calving. Cows should
be on a rising plane of nutrition up to calving with the aim to calve in good
condition. After calving, the cow has the potential to reach maximum
efficiency in milk production, but feed requirements for high production
are often greater than the voluntary intake of pasture can provide.
Therefore an energy supplement is required and there is evidence that
this will improve production and reproductive performance, and decrease
the risk of ketosis.
○
•
Dairy cows eat a lot!
Need to consume a lot of feed to achieve levels of production
Some cows produce more than 34,000 lbs of milk annually (over
4,200 gallons)
§
○
Nutrient needs vary tremendously throughout the lactation and dry
period cycle
○
At peak production, the dairy cow may require 3-10x as much protein as
energy as she required during late gestation
○
Further complicated by cows appetite - usually lags behind their nutrient
requirements
○
•
The cycle•
Relationships between milk production, dry matter intake and body
weight changes typically observed during normal
lactation/gestation cycle
§
Milk production increases rapidly and reaches peak production 6-9 weeks
after calving
○
Appetite lags behind production
Maximum daily dry matter intake occurs 12-15 weeks postpartum
§
Cows are in negative energy balance for 8-10 weeks
§
Makes up these nutrient deficits by borrowing from her body stores
§
○
Often lose 90-135 kg of body weight during early lactation
Supports 700-900 kg of milk production
§
○
After optimal dry matter intake is achieved
Intake follows production requirements and decreases as
production decreases
§
Tends to consume more than she needs during later lactation
Allows her to regain body weight lost in early lactation□
§
○
Should regain most of lost body weight during late lactation for optimal
energetic efficiency
○
Weight gain during the dry period accounted for by fetal growth
○
•
Bovine somatotropin
For cows injected with bovine somatotropin (bST), there may be a second
increase in production within a few days of initial injection
May again experience a short time of negative energy balance
§
○
Production typically increases about 10% as a result of bST injections
Dry matter intake needs to increase 2%-3% to supply nutrients
needed for increased production
§
○
Negative effects of bST?
FDA says bST is safest animal drug they ever produced. But causes
more consumer uproar than any others. Doesn’t matter if cow gets
bST. FDA says it is so safe because there are steroid hormones and
protein hormones. All negative media is from steroid hormones, but
average consumer doesn’t differentiate between the two. bST is a
protein and is specific to cows - only makes cows grow. Cows
naturally secrete their own growth hormone and it is immediately
digested by human stomachs and is biologically inactive. It doesn’t
work in humans either way! Concerned it would increase level of
milk production so much that it would lead to higher levels of
mastitis in the cow, leading to higher antibiotics in cow, leading to
higher chance of antibiotics in milk consumed by humans. Never
found. No difference in milk from treated and untreated cows. All
milk contains bST
§
○
•
Phased feeding
The lactation and gestation cycle can be divided into five phases based on
nutritional considerations:
Phase 1 - the first 10 weeks of lactation, when peak production
occurs, and body stores are used to make up for nutrient deficits
§
Phase 2 - about 10 weeks postpartum for most cows, continuing for
10-20 weeks. Maximum dry matter intake, and intake is in balance
with requirements.
§
Phase 3 - intake exceeds nutrient requirements for production,
restoring body reserves
§
Phase 4 - period for any final regain of body weight, and involution
followed by regeneration of secretory tissue in the udder for the
next lactation
Dry period□
§
Phase 5 - the last 1-3 weeks pre-partum
Dry period□
Transition period
Nutritionists tart increasing grain intake to prepare
rumen for increased nutritional intake that will follow
after cow gives birth
®
□
§
○
•
Dry Period
Need a short dry period as rest while preparing for the next lactation
Optimum dry period is 6-8 weeks
§
Dry periods shorter than 40 days do not allow enough time for
udder regeneration, which may cause a decrease in production
during the next lactation
§
○
Dry period - regenerate new secretory tissue and replace lost body
condition
Changes occur in the udder during the dry period:
Active involution; steady-state involution□
Lactogenesis plus colostrogenesis□
§
○
Involution
Active involution
Completed by 30 days into the dry period□
Milk-secreting tissue is reabsorbed□
§
Second stage, steady-state involution
Can exist indefinitely, and the mammary gland remains in a
collapsed state
□
§
Third stage, Lactogenesis plus colostrogenesis
Begins 15-20 days pre-partum□
Involves onset of lactation and the secretion of colostrum□
§
○
Dry-cow feeding emphasizes maintaining body condition
USDA research demonstrated that cows convert feed energy to
body tissue more efficiently in late lactation than during the dry
period
§
If still thin at drying off, need to replenish body stores as well as
provide for fetal growth
§
○
•
Body condition at calving
Body condition score of 3.5 at calving is ideal for high milk yield, high fat
test in milk, and reproductive performance
On a scale of 1-5
1 being very thin and 5 being excessively fat□
§
○
•
Dry-cow rations
Dry cow's nutrient requirements can often be met with only forages
Legume-grass hay and corn silage combination needs only vitamins
and a small amount of P
§
Dry-cow ration can be simple but should include the following
considerations:
Minimum of 1% of body weight as long-stem, dry forage
Preferably grass-hay
®
□
Free-choice feeding of corn silage should be avoid
Leads to excessive energy intake and increases
likelihood of displaced abomasum and fat cow
syndrome
®
□
Grain should be limited to energy and protein needs□
§
○
•
Fat cows
Consuming excess energy from grains and/or corn silage likely to develop
a disorder called fat cow syndrome
High blood lipid levels and fatty livers
§
More likely to have calving difficulties, displaced abomasums,
ketosis, and other health problems
§
○
Cows fed hay and/or haylage are less likely to have problems than cows
receiving free-choice corn silage
Limit corn silage for dry cows to 9.5-11 kg/day
Plus a protein and ca-P support□
§
○
•
More on bred heifers
Nutrient requirements of bred heifers during late gestation are slightly
greater than of dry cows
Bred heifers will likely need some grain along with forages during
the last 3-4 months of gestation (still growing)
§
Good-quality forages can provide all the nutrient needs
§
If forages are not of good quality or if heifers are exposed to severe
weather conditions:
Additional grain may be needed to maintain optimal growth
(not fat)
□
§
Should be in c]good condition but not fat at calving
Usually fed in groups of similar age or size□
§
○
•
Transition period (phase 5)
In the last weeks before parturition:
Aimed at adapting rumen microflora to higher-energy diets needed
postpartum
§
Adjustment often achieved by including small amounts of
ingredients of the lactating ration
Gradually increases concentrates□
This approach often called "steaming up:"□
Minimize the chances for milk fever and ketosis during
lactation
□
§
○
Most cows experience a sharp decrease in total dry matter intake 24-48
hours before calving
Stabilizing the rumen is important to avoid displaced abomasum,
acidosis, and off-feed
§
○
•
Following calving objectives:
Parturition until peak milk production is period when appetite lags behind
nutritional requirements (refer to graph) so peak milk production (phase
1) is negative nutrient balance period
Increase feed intake as rapidly as possible, but not to introduce
ration change so rapidly as to cause digestive upsets and off-feed
1.
Once the stress of calving has passed, concentrate intake can
gradually increase 0.5-0.7 kg/day
2.
If total mixed rations are fed, this equates to a forage-to-
concentrate ratio of 55:45 or 50:50
3.
○
•
Peak milk production
Forage portion of the diet not be less than 45% of dry matter
Successful phase 1 feeding:
Maximizes peak milk yield□
Utilizes some body weight as an energy source□
Minimizes ketosis□
Returns cows to a positive energy balance by 8-10 weeks
postpartum
□
§
○
Cows can compensate for much of their deficit in energy intake
Borrow remaining needed energy from body fat
§
Cannot borrow very much protein so protein must be supplied in
the diet
§
Early lactation cows will benefit from rumen bypass (escape)
proteins
Allows protein to bypass microbes in rumen and proceed
directly to abomasum where the cow can derive the benefits
from dietary protein
□
§
○
Non-protein nitrogen (NPN) supplements will not be efficiently used by
these cows
○
•
Peak milk production: acidosis
High starch, lower fiber diets are more apt to cause acidosis, digestive
upsets, and milk fat depression
Nonstructural carbohydrates (starches and sugars) should be
limited to 30-40% of the diet dry matter to avoid acidosis and other
metabolic problems
§
○
Feeds such as distiller's grains can replace a sizable amount of high starch
feeds while providing more energy and decreasing rumen acidosis
○
•
Peak milk production
Supplemental dietary fat
May allow increased energy density and adequate fiber intake
§
○
At least 2.25 kg of dry hay in the daily ration helps to maintain normal
rumination, especially during early lactation
Long stem is preferred over chopped hay
§
○
•
Maximum dry matter intake
Should be achieved as early in lactation as possible
○
Conception rates are greater for cows in positive energy balance
Cows are usually being bred during this phase in lactation
§
○
Body weights should stabilize, and weight gains should actually start
occurring during this phase
○
Maximum dry matter intake will reach 3.5-4.5% of body weight
○
Dry matter intakes are usually higher for higher producing cows
Not unusual for some cows to consume for than 5% of their body
weight
§
○
•
Sum it up!
We manage dairy cows on an annual gestation-lactation cycle
○
We can include body weight changes and dry matter intake and compare
them to milk production in the different phases of the cycle
○
The result is 5 distinct feeding phases
○
And during those phases we balance body weight changes with the
balance between concentrates and forages in the ration to maintain milk
production and healthy gut flora
○
•
Dairy Cattle
Thursday, April 27, 2017 9:55 AM
All metabolic diseases, all associated with a change in diet•
Acidosis
Rumen acidosis is a metabolic disease of cattle. Acidosis is said to occur
when the pH of the rumen falls less than 5.5. The change in acidity
changes the rumen flora, with acid-producing bacteria taking over. They
produce more acid, making the acidosis worse. The increased acid is then
absorbed through the rumen wall, causing metabolic acidosis, which in
severe cases can lead to shock and death
○
Cause: the primary cause of acidosis is feeding a high level of rapidly
digestible carbohydrate. In dairy cattle, acidosis is seen as a result of
feeding increased concentrates compared to forage
○
Symptoms: reduced feed intake, poor body condition and weight loss,
lethargy
○
•
Milk fever
Milk fever is a disorder mainly of dairy cows close to calving. It is a
metabolic disease caused by a low blood calcium level (hypocalcemia)
○
Losses are due to deaths (about 1 in 20 affected cows dies), a reduction in
the productive lifespan of each affected cow of about 3 years, and
reduction in milk production following each milk fever episode, as well as
costs of prevention and treatment
○
Symptoms: In typical cases cows show some initial excitement or agitation
and tremor in muscles of the head and limbs. Then they stagger and go
down to a "sitting" position, often with a 'kink' in her neck, and finally lie
flat on their side before circulatory collapse, coma and death
○
Causes: about 80% of cases occur within one day of calving because milk
and colostrum production drain calcium (and other substances) from the
blood, and some cows are unable to replace the calcium quickly enough.
High producers are more susceptible because the fall in their blood
calcium level is greater
○
Treatment: treated with oral calcium gel or boluses, or calcium gluconate
under their skin
○
•
Displaced abomasum
The abomasum (or true stomach) normally lies on the floor of the
abdomen, but can become filled with gas and rise to the top of the
abdomen, when it is said to be 'displaced'
○
Cause: the majority of cases occur soon after calving. During pregnancy
the uterus displaces the abomasum, so that after calving the abomasum
has to move back to its normal position, increasing the risk of
displacement
○
Symptoms: loss of appetite, drop in milk yield, reduced rumination, mild
diarrhea
○
Treatment: treatment requires replacing the abomasum in its normal
position. Preferably, the veterinarian also prevents recurrence by tackling
the abomasum to the body wall. Surgery can be preformed, however it
isn't always necessary. Often the abomasum can be returned to its usual
place by casting and rolling the animal onto its back, permitting the
abomasum to "float" back to its normal position
○
Prevention:
Prevention should be aimed at ensuring dry matter intake is
maintained in early lactation
§
Ensure cattle are not too fat at calving
§
Feed high quality feeds, with good quality forage
§
Feeding a total mixed ration as opposed to concentrates
§
Minimize changes between late dry and early lactation ration
§
It is likely that a farm with numerous DA problems is feeding the
late dry and/or early lactation cows
§
○
•
Ketosis
Ketosis is a metabolic disorder that occurs in cattle when energy demands
(ex high milk production) exceed energy intake and result in a negative
energy balance
○
Cause: when large amounts of body fat are utilized as an energy source to
support production, fat is sometimes mobilized faster than the liver can
properly metabolize it. If this situation occurs, ketone production exceeds
ketone utilization by the cow, and ketosis results. In the dairy cow, the
mismatch between input and output usually occurs in the first few weeks
of lactation, because the cow is not able to eat enough to match the
energy lost in the milk.
○
Symptoms: reduced milk yield, weight loss, reduced appetite, acetone
(pear drop) smell of breath/ or milk, some develop nervous signs including
excess salivation, licking, aggression etc
○
Treatment: The initial aim of treatment is to restore the lack of glucose in
the body. A quick-acting glucose supplement is required immediately.
Follow-up treatment is aimed at providing a long term supply of glucose.
○
The body condition of the dairy cow is important at calving. Cows should
be on a rising plane of nutrition up to calving with the aim to calve in good
condition. After calving, the cow has the potential to reach maximum
efficiency in milk production, but feed requirements for high production
are often greater than the voluntary intake of pasture can provide.
Therefore an energy supplement is required and there is evidence that
this will improve production and reproductive performance, and decrease
the risk of ketosis.
○
•
Dairy cows eat a lot!
Need to consume a lot of feed to achieve levels of production
Some cows produce more than 34,000 lbs of milk annually (over
4,200 gallons)
§
○
Nutrient needs vary tremendously throughout the lactation and dry
period cycle
○
At peak production, the dairy cow may require 3-10x as much protein as
energy as she required during late gestation
○
Further complicated by cows appetite - usually lags behind their nutrient
requirements
○
•
The cycle
•
Relationships between milk production, dry matter intake and body
weight changes typically observed during normal
lactation/gestation cycle
§
Milk production increases rapidly and reaches peak production 6-9 weeks
after calving
○
Appetite lags behind production
Maximum daily dry matter intake occurs 12-15 weeks postpartum
§
Cows are in negative energy balance for 8-10 weeks
§
Makes up these nutrient deficits by borrowing from her body stores
§
○
Often lose 90-135 kg of body weight during early lactation
Supports 700-900 kg of milk production
§
○
After optimal dry matter intake is achieved
Intake follows production requirements and decreases as
production decreases
§
Tends to consume more than she needs during later lactation
Allows her to regain body weight lost in early lactation□
§
○
Should regain most of lost body weight during late lactation for optimal
energetic efficiency
○
Weight gain during the dry period accounted for by fetal growth
○
•
Bovine somatotropin
For cows injected with bovine somatotropin (bST), there may be a second
increase in production within a few days of initial injection
May again experience a short time of negative energy balance
§
○
Production typically increases about 10% as a result of bST injections
Dry matter intake needs to increase 2%-3% to supply nutrients
needed for increased production
§
○
Negative effects of bST?
FDA says bST is safest animal drug they ever produced. But causes
more consumer uproar than any others. Doesn’t matter if cow gets
bST. FDA says it is so safe because there are steroid hormones and
protein hormones. All negative media is from steroid hormones, but
average consumer doesn’t differentiate between the two. bST is a
protein and is specific to cows - only makes cows grow. Cows
naturally secrete their own growth hormone and it is immediately
digested by human stomachs and is biologically inactive. It doesn’t
work in humans either way! Concerned it would increase level of
milk production so much that it would lead to higher levels of
mastitis in the cow, leading to higher antibiotics in cow, leading to
higher chance of antibiotics in milk consumed by humans. Never
found. No difference in milk from treated and untreated cows. All
milk contains bST
§
○
•
Phased feeding
The lactation and gestation cycle can be divided into five phases based on
nutritional considerations:
Phase 1 - the first 10 weeks of lactation, when peak production
occurs, and body stores are used to make up for nutrient deficits
§
Phase 2 - about 10 weeks postpartum for most cows, continuing for
10-20 weeks. Maximum dry matter intake, and intake is in balance
with requirements.
§
Phase 3 - intake exceeds nutrient requirements for production,
restoring body reserves
§
Phase 4 - period for any final regain of body weight, and involution
followed by regeneration of secretory tissue in the udder for the
next lactation
Dry period□
§
Phase 5 - the last 1-3 weeks pre-partum
Dry period□
Transition period
Nutritionists tart increasing grain intake to prepare
rumen for increased nutritional intake that will follow
after cow gives birth
®
□
§
○
•
Dry Period
Need a short dry period as rest while preparing for the next lactation
Optimum dry period is 6-8 weeks
§
Dry periods shorter than 40 days do not allow enough time for
udder regeneration, which may cause a decrease in production
during the next lactation
§
○
Dry period - regenerate new secretory tissue and replace lost body
condition
Changes occur in the udder during the dry period:
Active involution; steady-state involution□
Lactogenesis plus colostrogenesis□
§
○
Involution
Active involution
Completed by 30 days into the dry period□
Milk-secreting tissue is reabsorbed□
§
Second stage, steady-state involution
Can exist indefinitely, and the mammary gland remains in a
collapsed state
□
§
Third stage, Lactogenesis plus colostrogenesis
Begins 15-20 days pre-partum□
Involves onset of lactation and the secretion of colostrum□
§
○
Dry-cow feeding emphasizes maintaining body condition
USDA research demonstrated that cows convert feed energy to
body tissue more efficiently in late lactation than during the dry
period
§
If still thin at drying off, need to replenish body stores as well as
provide for fetal growth
§
○
•
Body condition at calving
Body condition score of 3.5 at calving is ideal for high milk yield, high fat
test in milk, and reproductive performance
On a scale of 1-5
1 being very thin and 5 being excessively fat□
§
○
•
Dry-cow rations
Dry cow's nutrient requirements can often be met with only forages
Legume-grass hay and corn silage combination needs only vitamins
and a small amount of P
§
Dry-cow ration can be simple but should include the following
considerations:
Minimum of 1% of body weight as long-stem, dry forage
Preferably grass-hay
®
□
Free-choice feeding of corn silage should be avoid
Leads to excessive energy intake and increases
likelihood of displaced abomasum and fat cow
syndrome
®
□
Grain should be limited to energy and protein needs□
§
○
•
Fat cows
Consuming excess energy from grains and/or corn silage likely to develop
a disorder called fat cow syndrome
High blood lipid levels and fatty livers
§
More likely to have calving difficulties, displaced abomasums,
ketosis, and other health problems
§
○
Cows fed hay and/or haylage are less likely to have problems than cows
receiving free-choice corn silage
Limit corn silage for dry cows to 9.5-11 kg/day
Plus a protein and ca-P support□
§
○
•
More on bred heifers
Nutrient requirements of bred heifers during late gestation are slightly
greater than of dry cows
Bred heifers will likely need some grain along with forages during
the last 3-4 months of gestation (still growing)
§
Good-quality forages can provide all the nutrient needs
§
If forages are not of good quality or if heifers are exposed to severe
weather conditions:
Additional grain may be needed to maintain optimal growth
(not fat)
□
§
Should be in c]good condition but not fat at calving
Usually fed in groups of similar age or size□
§
○
•
Transition period (phase 5)
In the last weeks before parturition:
Aimed at adapting rumen microflora to higher-energy diets needed
postpartum
§
Adjustment often achieved by including small amounts of
ingredients of the lactating ration
Gradually increases concentrates□
This approach often called "steaming up:"□
Minimize the chances for milk fever and ketosis during
lactation
□
§
○
Most cows experience a sharp decrease in total dry matter intake 24-48
hours before calving
Stabilizing the rumen is important to avoid displaced abomasum,
acidosis, and off-feed
§
○
•
Following calving objectives:
Parturition until peak milk production is period when appetite lags behind
nutritional requirements (refer to graph) so peak milk production (phase
1) is negative nutrient balance period
Increase feed intake as rapidly as possible, but not to introduce
ration change so rapidly as to cause digestive upsets and off-feed
1.
Once the stress of calving has passed, concentrate intake can
gradually increase 0.5-0.7 kg/day
2.
If total mixed rations are fed, this equates to a forage-to-
concentrate ratio of 55:45 or 50:50
3.
○
•
Peak milk production
Forage portion of the diet not be less than 45% of dry matter
Successful phase 1 feeding:
Maximizes peak milk yield□
Utilizes some body weight as an energy source□
Minimizes ketosis□
Returns cows to a positive energy balance by 8-10 weeks
postpartum
□
§
○
Cows can compensate for much of their deficit in energy intake
Borrow remaining needed energy from body fat
§
Cannot borrow very much protein so protein must be supplied in
the diet
§
Early lactation cows will benefit from rumen bypass (escape)
proteins
Allows protein to bypass microbes in rumen and proceed
directly to abomasum where the cow can derive the benefits
from dietary protein
□
§
○
Non-protein nitrogen (NPN) supplements will not be efficiently used by
these cows
○
•
Peak milk production: acidosis
High starch, lower fiber diets are more apt to cause acidosis, digestive
upsets, and milk fat depression
Nonstructural carbohydrates (starches and sugars) should be
limited to 30-40% of the diet dry matter to avoid acidosis and other
metabolic problems
§
○
Feeds such as distiller's grains can replace a sizable amount of high starch
feeds while providing more energy and decreasing rumen acidosis
○
•
Peak milk production
Supplemental dietary fat
May allow increased energy density and adequate fiber intake
§
○
At least 2.25 kg of dry hay in the daily ration helps to maintain normal
rumination, especially during early lactation
Long stem is preferred over chopped hay
§
○
•
Maximum dry matter intake
Should be achieved as early in lactation as possible
○
Conception rates are greater for cows in positive energy balance
Cows are usually being bred during this phase in lactation
§
○
Body weights should stabilize, and weight gains should actually start
occurring during this phase
○
Maximum dry matter intake will reach 3.5-4.5% of body weight
○
Dry matter intakes are usually higher for higher producing cows
Not unusual for some cows to consume for than 5% of their body
weight
§
○
•
Sum it up!
We manage dairy cows on an annual gestation-lactation cycle
○
We can include body weight changes and dry matter intake and compare
them to milk production in the different phases of the cycle
○
The result is 5 distinct feeding phases
○
And during those phases we balance body weight changes with the
balance between concentrates and forages in the ration to maintain milk
production and healthy gut flora
○
•
Dairy Cattle
Thursday, April 27, 2017 9:55 AM
Document Summary
All metabolic diseases, all associated with a change in diet. Rumen acidosis is a metabolic disease of cattle. Acidosis is said to occur when the ph of the rumen falls less than 5. 5. The change in acidity changes the rumen flora, with acid-producing bacteria taking over. They produce more acid, making the acidosis worse. The increased acid is then absorbed through the rumen wall, causing metabolic acidosis, which in severe cases can lead to shock and death. Cause: the primary cause of acidosis is feeding a high level of rapidly digestible carbohydrate. In dairy cattle, acidosis is seen as a result of feeding increased concentrates compared to forage. Symptoms: reduced feed intake, poor body condition and weight loss, lethargy. Milk fever is a disorder mainly of dairy cows close to calving. It is a metabolic disease caused by a low blood calcium level (hypocalcemia)
