Nutritional Management of the Calving and Lactating Cow Flashcards
What are the risks of having a low body condition score (BCS) at calving in dairy herds?
- Decreased dominant follicle diameter
- Reduced insulin and IGF-1
- Low LH pulse frequency
• Poor Fertility!
- Plus increased risk of :
- Retained placenta
- anoestrous
- metritis
- Lameness
- All of which contribute to further reductions in conception rate and increased days open (not in calf)
What are the risks of having a high BCS at calving in dairy herds?
- Increased risk of:
- Metritis • Ketosis
- Milk fever
- Cystic ovaries
- All of which are likely to reduce conception rate and increase days open
• Poor fertility!
What is the recommended BCS for calving?
Avoid more than …. loss from partition to insemination
- Calve in BCS 3 (on a scale of 1 to 5)
- 5 on a scale of 1 to 9
- Midrange
- Avoid more than 0.5BCS loss from parturition to insemination/joining
- Quality & quantity of DMI
High ….. can reduce progesterone [] and can lead to embryo loss
High DMI/energy
High ….. and high …. in diet around insemination reduces chances of conseption
high protein and high energy
How do we calculate the mineral requirement for a lactating cow?
- Requirements calculated in similar way to energy and protein i.e. replace endogenous losses (faeces, urine skin)
- Using factorial methods and balance studies
- Recommended feeding values
- Requirements are usually in gross amounts
- Need to consider availability in feed
Ca and P in regards to lactation?
- Net req. for lactation is amount deposited in milk
- milk quality
- High at peak lactation
- may be difficult to obtain all from diet
- Absorption highly variable
- **Ratio important
- MORE CA THAN P**
Where does most Ca loss occur?
How can we combat these losses through nutrition?
- Renal losses small, but can be elevated with anionic feeds
- Negatively charged feeds (salts)
• DCAD (Dietary Cation Anion Difference)
- Prevent hypocalcaemia during transition
- Most lost through faeces, colostrum and milk
- PTH and 1,25-dihydroxycholecalciferol (calcitriol or 1,25- dihydroxyvitamin D3 ) and calcitonin key hormones
What is the process of hyPOcalcaemia (low)?
- PTH synthesised by parathyroid gland
- Stimulates Ca resorption from bone
- PTH stimulates calcitriol synthesis in kidneys from precursor (25 hydroxyvitamin D3 )
- Stimulates Ca transport proteins in gut to absorb more Ca, also stimulates Ca resorption
- Requires vitamin D from diet or synthesis from cholesterol in skin on UV exposure
What is the process of hyPERcalcaemia (high)?
Calcitonin released from thyroid gland to promote bone mineralisation and reduce renal Ca reabsorption (increasing Ca excretion)
What are the direct economic costs of milk fever?
- Treatment cost and reduced milk yield
- 4-28% of cows relapse and may become ‘downer’ cows (20-67% of these die)
What are the indirect economic costs of milk fever?
- Dystocia
- poor appetite
- uterine prolapse
- retained placenta
- Metritis (inflammation of uterine wall)
- displaced abomasum
- greater risk of developing ketosis and mastitis
- All related to reduced muscle function
- Low [Ca] also reduces insulin production
What are the dietary options for reducing milk fever?
Ca and vitamin D
• Manipulating dietary cation-anion difference (DCAD) by feeding anionic salts
- Mobilise Ca from bones during transition
- Replenishing Ca reserves
What are the non-diet risk factors associated with milk fever?
•Breed
- Channel Island breeds most susceptible
- Reduced concentration of intestinal receptors for calcitriol
- *• Climate**
- Incidence increases with evaporation rate
- Greatest in cold, wet weather when big difference between max and min temperatures
- Related to DMI and stress-induced adreno-cortical hyperactivity
- Ca and Mg metabolism alter in cold-stressed sheep
- Greater Ca excretion and lower plasma [Mg]
How can we manage milk fever?
-think age, BCS, genetics
- Management
- Greater in older cows
- Reduced ability to mobilise bone Ca, reduced calcitriol production, reduced number of intestinal Ca receptors (ie less Ca absorbed)
- Greater if BCS >3.5 and <2.5
- Reduced DMI
- Greater tissue catabolism
- Increased milk protein (and therefore Ca secretion)
- Greater in assisted cows
- Less in induced cows and twin-bearers
- More favourable physiological status
- Genetics
- More likely if already had Milk Fever
- h2 estimates 0.09-0.13
