3 Mammalian Nutrition Flashcards
(25 cards)
What are the stages of the lactation cycle?
Mammogenesis → Lactogenesis I & II → Galactopoiesis → Involution
Which hormones regulate milk synthesis?
Estrogen, progesterone, prolactin, growth hormone, IGF-1, placental lactogen
What are the major milk components?
Fat, protein (casein, whey), lactose, and minerals
What stimulates nervous control of milk synthesis?
External cues like suckling reflex and stress
What are the main precursors for milk synthesis?
Glucose, acetate, BHBA, triglyceride fatty acids, amino acids
What are the primary milk proteins?
Casein, alpha-lactalbumin, beta-lactoglobulin
What is the key enzyme for lactose synthesis?
Lactose synthetase
How do ruminants obtain glucose?
From gluconeogenesis and propionate absorption
What percentage of available glucose can high-yielding cows use for milk production?
60–85%
What is a QTL?
Quantitative Trait Locus – a genomic region linked to a specific trait
What is a SNP?
Single Nucleotide Polymorphism – a one-base-pair change in DNA
What tools are used to identify genes affecting milk traits?
GWAS (Genome-Wide Association Studies), TWAS, bioinformatics
Where are short and medium-chain fatty acids synthesized?
In the mammary gland via de novo synthesis
What determines milk fat composition?
Diet, genetics, and de novo synthesis
How does feeding unsaturated fats affect milk?
Increases unsaturated fatty acid content in milk
What is the main carbon source for fatty acid synthesis in ruminants?
Acetate
What is required for milk protein synthesis?
Essential amino acids and hormonal signals (GH, IGF-1)
How can diet modify milk protein?
High-quality forage and protein-rich diets can enhance protein content
What is lactose composed of?
Glucose + Galactose
What happens to lactose during digestion?
It’s broken down by lactase into glucose and galactose
Which volatile fatty acids (VFAs) are important for milk fat?
Acetate and propionate
How does increasing acetate affect milk?
Increases milk fat content
How does increasing propionate affect milk?
Increases milk protein and lactose
What is the traditional view of milk fat and heart disease?
Saturated fat raises LDL and increases CHD risk
