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Maximizing Calf Health: Part 1

Christine B. Navarre, DVM, MS, DACVIM
Extension Veterinarian
Louisiana State University Agricultural Center
Baton Rouge, LA 70803
cnavarre@agcenter.lsu.edu

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Maximizing Calf Survivability
- Crucial to economic success of producers
- Starts months before calf is born
- Proper nutrition and environment will minimize problems

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Nutrition
- Undernutrition in last trimester
- Prolonged labor-stillbirths, dummies
- Low birthweights and poor vigor
- Failure of passive transfer (FPT)
- Cold stress
- Low disease resistance
- Need good records to recognize

- Overnutrition
- Dystocia, poor milk production

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Nutrition
- Impact on immune system
- If cow can’t maintain body condition
- Can’t make antibodies
- Can’t respond to vaccines
- FPT
- Poor cell mediated immunity

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Nutrition During Gestation of Beef Cows

Importance of high quality colostrum within 4 hours of birth
Serum IgG levels at 24 hours and calf health and gain to weaning

IgG INADEQUATE ADEQUATE
CALVES 60 183
% MORBIDITY 25 4.9
WEAN WT. LBS 471 495
Am J. Vet Res 56:1149

Bob Sager, DVM

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Nutrition and Calf Numbers, Health, Growth and Production
- Poor nutrition in late gestation=few lighter calves at weaning/slaughter and or poor milk production for years to come
- Increased dystocia=increase stillbirths/weak calves=more sick calves=more deaths/poor growth
- Increased FPT due to quality of colostrum=sick calves=death/poor growth
- Decreased calf birth weight=less fat=cold/sickness =death/poor growth
- Poor vaccine responses
- Poor fertility=less calves in two years
- Replacement heifer fertility=less calves for years
- Milk production decreased

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BCS (Nutrition) Will Affect:
- Conception / Pregnancy Rate
- Date of Conception
- Level of Dystocia
- Calf Health and Vigor
- Preweaning Calf Performance
- Postweaning Calf Performance

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Fetal Programming (Developmental Programming)
- The concept that a maternal stimulus or insult at a critical period in fetal development has long term impacts on offspring
- Nutritional stress most studied
- Humans
- Malnourishment in first half of pregnancy
- Offspring have increased incidence of diabetes, obesity, CV disease, behavioral problems
- Two mechanisms
- Direct damage to tissue/organ structure (one off)
- Epigenetic changes (potentially multigenerational)

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Nutrition in Bovine Fetal Programming

Muscle development occurs early

Cadra Van Bibber-Krueger, Ph.D., Beef Nutritionist, Hubbard Feeds

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Critical period for the formation of intramuscular adipocytes
Fattening, intramuscular adipocyte hypertrophy

Intramuscular fat

Other fat depots

Conception Mid-gestation Birth 250 d Slaughter

Muscle fiber formation Muscle fiber hypertrophy and lengthening

Adipocyte hyperplasia
Adipocyte hypertrophy

Min Du, et al., 2015

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Fetal Programming-Cattle
- Nutritional stress-mainly protein
- 1st and 2nd trimesters (coincides with high lactation demands)
- Organ development and vascularization/placental development
- Reduced caruncular and cotyledonary weights
- Reduced fetal weights
- Fewer glomeruli
- Respiratory disease increased

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Fetal Programming-Cattle
- 1st and 2nd trimesters
- Reduced number skeletal muscle fibers and intramuscular adipocytes
- Vulnerable because low priority compared to heart, brain and others
- Decreased ADG, gain:feed, total gain, final wt.
- Insulin resistance at end of feeding period
- Tenderness
- Number of oocytes available for life
- Testicular development?

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Fetal Programming-Cattle
- Nutritional stress-studies have mainly looked at protein
- 2nd and 3rd trimesters
- Birthweight-mixed results
- Growth (48 lb at weaning)
- Marbling decreased
- Reproduction in female offspring decreased
- Altered hormone secretion?

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Epigenetics
- The study of heritable changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA sequence
- Functionally relevant modifications to the genome that do not involve a change in the nucleotide sequence
- Examples-DNA methylation and histone modification, both of which serve to regulate gene expression without altering the underlying DNA sequence
- These mechanisms can enable the effects of parents experiences to be passed down to subsequent generations
- Adverse long-term effects reflect a mismatch between fetal environmental conditions and the conditions that the individual will confront later in life

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Epigenetics
- “Thrifty genotype” hypothesis
- Thrifty genes selected during hunter-gatherer periods (food is scarce), increase capacity to store fat, increasing risk of insulin resistance later when food is abundant
- Good
- Selection of brood cows for a certain environment?
- Bad
- Calves born to cows in good environment expected to perform in hostile environment (herd bulls)
- Calves born to cows in hostile environment expected to grow and perform when given good nutrients
- Good genetics masked leading to poor phenotype and bad genetic selection decisions
- Temperament?
- Pregnant cattle moved or transported-more aggressive calves (Brahman’s, TX)
- Ron Randel, TAMU
- Breed differences?
- Brahmans slower growth in early mid gestation then compensatory later

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Neonatal Immunity
- Immature mucosal immunity
- Agammaglobulinemic
- Immature cellular immunity
- Normal microbial flora lacking
- Neutral abomasal pH

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Passive Transfer of Immunity
- Provides
- Circulating immunoglobulins
- Local immunoglobulins
- WBCs
- Nutrition
- Closure

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Failure of Passive Transfer
- Disease prevention
- Growth
- Not a death sentence
- Adequate PT can be overwhelmed
- If kept to a minimum, the few calves with FPT will have minimal exposure to disease

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Failure of Passive Transfer
- Low immunoglobulin concentration
- Inappropriate colostral immunoglobulins
- Failure to ingest adequate amounts
- Failure to absorb adequate amounts

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Failure of Passive Transfer
- Low immunoglobulin concentration
- Poor nutrition
- High producing cows
- Pure-breds vs. cross-breds
- Primiparous vs. multiparous
- Leaking
- Premature delivery
- Short dry period

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Failure of Passive Transfer
- Inappropriate colostral immunoglobulins
- Different source
- Poor vaccination history
- Failure to ingest adequate amounts
- Weak calves (nutrition!)
- Poor udder conformation
- Poor mothering
- Poor environment

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IMAGE

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IMAGE

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Failure of Passive Transfer
- Failure to absorb adequate amounts
- Calf nurses too late
- Poor mothering
- Dystocia
- Prematurity?
- Tube feeding?
- Prolonged gestation?

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Failure of Passive Transfer: Diagnosis
- Serum/plasma protein
- Serum protein > 5.5 g/dl
- 24 hours to 7 days
- Sick and normal calves

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Failure of Passive Transfer: Treatment
- Prophylactic antibiotics?
- Plasma/whole blood transfusions?

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Failure of Passive Transfer Prevention
- Beef calves: when to intervene
- Dystocia
- Weak calf
- Poor udder conformation
- Suspect poor quality or quantity colostrum

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FPT Prevention (Individual Calf)
- Avoid commercial colostrum supplements
- Colostrum replacers better (2 doses)
- Frozen colostrum from farm
- Let calf nurse if it will, but if it won’t tube it!!!!
- 2 liters beef, 4 liters dairy colostrum
- Biosecurity

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FPT Prevention (Herd)
- Nutrition
- Good environment
- Minimize dystocia
- Culling practices

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Sanitation-Beef
- Adequate PT status can be overwhelmed by contaminated environment
- Move hay and feed troughs/place away from water source and shelter
- Segregate according to calf age
- Sandhills segregation system
- In outbreak
- Move pregnant animals