Case 4 Milk
1.0 Introduction
1.1 History of cattle production
o Cattle domestication = 9000 and 8000 BC
o Current cattle population = 1.5 billion head, 18% dairy cows 0.6% in NL
o 656 million tonnes milk production worldwide annual (12 mill in NL)
o Number of dairy farms is decreasing, number of cows per farm is increasing, average milk
yield per cow per year is increasing
1.2 Breeds
o Most kept dairy cow in NL and worldwide is Holstein Friesian. Because it’s easier to focus on
a specific breeding programme for single breed
o Other milk production cows: MRIJ and Jersey
1.3 Milk composition
o Global demand for and consumption of animal products is increasing with world population
and will keep on doing so in the future.
2.0 Milk production
2.1 Bovine oestrous cycle and milk production
o Oestrous cycle of ± 21 days. Starts at puberty (8 months)
o Oestrous cycle divided into luteal and follicular phase
o Luteal phase comprises a metestrus and a dioestrus. Starts with ovulation and lasts until
regression of corpus luteum.
o Follicular phase comprises a proestrus and an oestrus. Period between regression of a corpus
luteum and ovulation.
o Corpus luteum is the structure that remains when follicle has ruptured from ovary during
previous ovulation.
o Progesterone (P4): produced by corpus luteum. Function to maintain an appropriate uterine
endometrium for potential embryo to develop in. Concentration increase during luteal
phase. No fertilization corpus luteum degenerates, stops producing P4, another follicle
will grow and rupture from ovary under influence of oestrogen (E2) during follicular phase =
new ovulation = new luteal phase.
o End of follicular phase: cow is in oestrus (cow shows typical behaviours (mounting or
standing to be mounted), lasts 15-18 hours)
o Insemination: ideal time for insemination is within 25-36 hours after oestrous detection
(standing to be mounted or pedometers, especially useful for first service cows in which
oestrous behaviour is often absent ), at 15 months of age, first calve at 24 months. Gestation
period of ±285 days
o Cow dried off at ±42-60 days before calving, after dry period cow will calve and start
producing milk
o Calving interval reflects the period between one calving and the next. In NL ±413 days
o After initiation of puberty during several subsequent oestrous cycles, mammary gland
(borstklier) starts to grow and form a duct with alveoli (longblaasjes).
1.0 Introduction
1.1 History of cattle production
o Cattle domestication = 9000 and 8000 BC
o Current cattle population = 1.5 billion head, 18% dairy cows 0.6% in NL
o 656 million tonnes milk production worldwide annual (12 mill in NL)
o Number of dairy farms is decreasing, number of cows per farm is increasing, average milk
yield per cow per year is increasing
1.2 Breeds
o Most kept dairy cow in NL and worldwide is Holstein Friesian. Because it’s easier to focus on
a specific breeding programme for single breed
o Other milk production cows: MRIJ and Jersey
1.3 Milk composition
o Global demand for and consumption of animal products is increasing with world population
and will keep on doing so in the future.
2.0 Milk production
2.1 Bovine oestrous cycle and milk production
o Oestrous cycle of ± 21 days. Starts at puberty (8 months)
o Oestrous cycle divided into luteal and follicular phase
o Luteal phase comprises a metestrus and a dioestrus. Starts with ovulation and lasts until
regression of corpus luteum.
o Follicular phase comprises a proestrus and an oestrus. Period between regression of a corpus
luteum and ovulation.
o Corpus luteum is the structure that remains when follicle has ruptured from ovary during
previous ovulation.
o Progesterone (P4): produced by corpus luteum. Function to maintain an appropriate uterine
endometrium for potential embryo to develop in. Concentration increase during luteal
phase. No fertilization corpus luteum degenerates, stops producing P4, another follicle
will grow and rupture from ovary under influence of oestrogen (E2) during follicular phase =
new ovulation = new luteal phase.
o End of follicular phase: cow is in oestrus (cow shows typical behaviours (mounting or
standing to be mounted), lasts 15-18 hours)
o Insemination: ideal time for insemination is within 25-36 hours after oestrous detection
(standing to be mounted or pedometers, especially useful for first service cows in which
oestrous behaviour is often absent ), at 15 months of age, first calve at 24 months. Gestation
period of ±285 days
o Cow dried off at ±42-60 days before calving, after dry period cow will calve and start
producing milk
o Calving interval reflects the period between one calving and the next. In NL ±413 days
o After initiation of puberty during several subsequent oestrous cycles, mammary gland
(borstklier) starts to grow and form a duct with alveoli (longblaasjes).
