ANFS251 Exam 4
An annual production cycle in dairy cows that
links pregnancy (gestation), calving, milk
gestation-lactation cycle production (lactation), and the dry period;
nutrition is adjusted as the cow moves through
each phase
The pattern of milk output after calving:
production rises rapidly, peaks (often ~6–9
milk production curve
weeks postpartum), and then gradually declines
through late lactation
The amount of feed consumed excluding water;
Dry matter intake (DMI) DMI typically lags behind milk production early
in lactation, creating a nutrient deficit.
A period (commonly ~8–10 weeks, sometimes
longer) when energy required for milk
Negative Energy Balance (NEB)
production exceeds energy consumed; cows
compensate by mobilizing body reserves
Use of stored body fat (and to a limited extent
body protein) to supply energy and nutrients
Body Reserve Mobilization
when intake is inadequate—especially during
early lactation
The period after calving; early postpartum is
Postpartum high-risk for metabolic disorders because intake
often lags behind production
The highest daily milk output during lactation,
usually occurring several weeks after calving;
Peak milk (peak production)
strongly influenced by how well intake rises after
calving
How well milk production is maintained after
peak; in late lactation, producers aim to
Milk persistency
maintain persistency while rebuilding body
condition.
A metabolic disorder often linked to high-starch,
low-fiber diets that disrupt rumen fermentation
Acidosis (Rumen Acidosis)
and can cause digestive upset, reduced
performance, and milk fat depression
, A metabolic disease around calving associated
Milk Fever with calcium imbalance; nutrition during the
transition period can influence risk.
A disorder where the abomasum shifts from its
normal position; risk increases with poor rumen
Displaced Abomasum (DA)
fill, inconsistent intake, and excessive energy
intake (e.g., free-choice corn silage for dry cows).
A metabolic disorder associated with severe
negative energy balance and excess
Ketosis
mobilization of body fat; management focuses
on increasing intake and energy density safely
A condition linked to over-conditioning (excess
energy intake) before calving; characterized in
Fat Cow Syndrome the lecture by high blood lipid levels and fatty
liver, increasing risk of calving and post-calving
problems
Approximately the first ~10 weeks of lactation
when milk production rises to peak and cows
Phase 1 (Early Lactation/Peak Milk Phase) typically experience negative nutrient balance;
goal is rapid DMI increase without causing
digestive upsets.
Begins around ~10 weeks postpartum; DMI is
Phase 2 (Mid-Lactation/Maximal Intake Phase) near maximum and more closely matches
nutrient requirements.
A period when intake exceeds requirements for
Phase 3 (Late Lactation/Body Reserve
milk production; goal is to restore body reserves
Restoration)
efficiently for the next lactation
The earlier portion of the dry period focused on
mammary gland involution and preparing for
Phase 4 (Dry period)
the next lactation while maintaining appropriate
body condition.
The last ~1–3 weeks before calving; grain and
lactation-ingredient exposure are increased
Phase 5 (Transition Period)
gradually to adapt rumen microbes and help
reduce metabolic disease risk
A planned rest period between lactations
(optimal ~6–8 weeks) that allows udder tissue
Dry period regeneration and supports fetal growth; too
short (<~40 days) can reduce next-lactation
production.
Involution (udder involution) The process of the mammary gland regressing
after drying off; milk-secreting tissue is
An annual production cycle in dairy cows that
links pregnancy (gestation), calving, milk
gestation-lactation cycle production (lactation), and the dry period;
nutrition is adjusted as the cow moves through
each phase
The pattern of milk output after calving:
production rises rapidly, peaks (often ~6–9
milk production curve
weeks postpartum), and then gradually declines
through late lactation
The amount of feed consumed excluding water;
Dry matter intake (DMI) DMI typically lags behind milk production early
in lactation, creating a nutrient deficit.
A period (commonly ~8–10 weeks, sometimes
longer) when energy required for milk
Negative Energy Balance (NEB)
production exceeds energy consumed; cows
compensate by mobilizing body reserves
Use of stored body fat (and to a limited extent
body protein) to supply energy and nutrients
Body Reserve Mobilization
when intake is inadequate—especially during
early lactation
The period after calving; early postpartum is
Postpartum high-risk for metabolic disorders because intake
often lags behind production
The highest daily milk output during lactation,
usually occurring several weeks after calving;
Peak milk (peak production)
strongly influenced by how well intake rises after
calving
How well milk production is maintained after
peak; in late lactation, producers aim to
Milk persistency
maintain persistency while rebuilding body
condition.
A metabolic disorder often linked to high-starch,
low-fiber diets that disrupt rumen fermentation
Acidosis (Rumen Acidosis)
and can cause digestive upset, reduced
performance, and milk fat depression
, A metabolic disease around calving associated
Milk Fever with calcium imbalance; nutrition during the
transition period can influence risk.
A disorder where the abomasum shifts from its
normal position; risk increases with poor rumen
Displaced Abomasum (DA)
fill, inconsistent intake, and excessive energy
intake (e.g., free-choice corn silage for dry cows).
A metabolic disorder associated with severe
negative energy balance and excess
Ketosis
mobilization of body fat; management focuses
on increasing intake and energy density safely
A condition linked to over-conditioning (excess
energy intake) before calving; characterized in
Fat Cow Syndrome the lecture by high blood lipid levels and fatty
liver, increasing risk of calving and post-calving
problems
Approximately the first ~10 weeks of lactation
when milk production rises to peak and cows
Phase 1 (Early Lactation/Peak Milk Phase) typically experience negative nutrient balance;
goal is rapid DMI increase without causing
digestive upsets.
Begins around ~10 weeks postpartum; DMI is
Phase 2 (Mid-Lactation/Maximal Intake Phase) near maximum and more closely matches
nutrient requirements.
A period when intake exceeds requirements for
Phase 3 (Late Lactation/Body Reserve
milk production; goal is to restore body reserves
Restoration)
efficiently for the next lactation
The earlier portion of the dry period focused on
mammary gland involution and preparing for
Phase 4 (Dry period)
the next lactation while maintaining appropriate
body condition.
The last ~1–3 weeks before calving; grain and
lactation-ingredient exposure are increased
Phase 5 (Transition Period)
gradually to adapt rumen microbes and help
reduce metabolic disease risk
A planned rest period between lactations
(optimal ~6–8 weeks) that allows udder tissue
Dry period regeneration and supports fetal growth; too
short (<~40 days) can reduce next-lactation
production.
Involution (udder involution) The process of the mammary gland regressing
after drying off; milk-secreting tissue is
