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Animal nutrition > Animal nutrition - calves & heifers > Flashcards

Animal nutrition - calves & heifers Flashcards

1
Q

the costs of rearing young cattle form about ?% of milk production costs

A

20…25% of milk production costs

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2
Q

For young stock rearing two things must be
controlled and followed:

A
  1. feeding scheme during rearing
  2. insemination age

these are both limited by biological aspects and affect future milk performance

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3
Q

in calves, the rumen volume contributes only what percentage?

A

25%

Rumen wall is smooth, slightly transparent and thin in newborn calves.
Rumen + omasum are 2 times smaller than the abomasum.

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4
Q

at week 10-12, calf forestomachs and abomasum volume are

A

fore-stomachs 14 l and abomasum 7 l

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5
Q

Protein digestion in calves.
Up to 4 weeks of age, what enzyme dominates?

A

rennin-cathepsin digestion

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6
Q

rennin-cathepsin do what to milk proteins

A

rennin coagulates and
cathepsin hydrolyses milk proteins at pH 5

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7
Q

what activates cathepsin?

A

lactic acid

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8
Q

lactic acid bacteria use what as substrate in calves?

A

lactose

then they produce necessary amounts of lactic acid to activate cathepsin

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9
Q

At the age of one month, what digestion starts in calves

A

At the age of one month HCl-pepsin digestion starts

– pepsinogen -> pepsin + HCl; works at pH 2
– activity of HCl-pepsin digestion increases with
addition of solid feed into the ration

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10
Q

cells producing HCl in the stomach develop at what age

A

cells producing HCl in the stomach develop at 31 days
of life

– rapid decline occurs after weaning

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11
Q

Pancreatic protease activity is what at birth

A

Pancreatic protease activity is low at birth

– a few days after birth activity begins to
increase rapidly

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12
Q

similar Pancreatic protease activity to the adult is achieved

A

8…9 weeks after birth

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13
Q

How well is Milk protein digested in calves

A

Milk protein is digested well ( >95%)

NB! the digestibility of vegetable proteins used in whole-milk replacer is much lower, and
therefore should not be used on first month

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14
Q

Fat digestion in calves.

Lipase is present in the saliva up to the end of
the

A

3rd month of life.

– lipase activity is greater if calves drink milk from
a teat

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15
Q

Calf Saliva lipase hydrolyses what length fatty acids very actively

A

Saliva lipase hydrolyses FAs C4 to C10 very actively

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16
Q

Calf Saliva lipase hydrolyses what length fatty acids less actively

A

Saliva lipase hydrolyses FAs C12 to C14 a bit less

– does not hydrolyse longer chain FAs

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17
Q

Salivary lipase activity is optimal at pH

A

4.5-6.0 and this occurs primarily in the milk coagulate

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18
Q

The main fat digestion in calves, occurs where by what

A

The main fat digestion occurs in the small
intestine by the pancreatic lipase

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18
Q

The main fat digestion in calves, occurs where by what

A

The main fat digestion occurs in the small
intestine by the pancreatic lipase

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19
Q

Calves digest fats generally well:
– short C-chain FAs (up to C10) absorbed already where at a rate of?

A

in the abomasum at a rate of 100%

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20
Q

Calves digest fats generally well:
– medium C-chain FAs (C12-14) absorbed where at a rate of?

A

in the small intestine at a rate of 95%

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21
Q

Calves digest fats generally well:
long C-chain FAs (C16 and more) absorbed where at a rate of?

A

in the small intestine at a rate of 80…90%

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22
Q

Milk fat is digested well by calves. At what rate?

A

100%

– in whole-milk replacers prefer short chain FAs,
vegetable fats can be used, but must be homogenised

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23
Q

Main Carbohydrate digestion in calves occurs in what by what

A

in the small intestine by the enzyme lactase

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24
Q

The activity of lactase is lower in what week of life

A

The activity of lactase is lower in the first week
of life, then increases and remains stable by 8
weeks of life, and then drops again

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25
Q

Digestion of other di- and polysaccharides,
besides lactose, is how in calves?

A

is limited in young calves, because they don’t have suitable enzymes (e.g. amylase, sucrase), or their activity is very low and not comparable to piglets

26
Q

Colostrum compared to normal milk contains higher

A

DM, protein, fat, vitamins and minerals

obv contains a relatively high amount of albumins
and globulins

27
Q

Colostrum protein composition is close to

A

blood protein composition

28
Q

Colostrum acidity is?
and promotes?

A

high, and promotes coagulation of casein

29
Q

Colostrum contains what type of inhibitors to prevent hydrolysis of?

A

contains trypsin and chymosin inhibitors to
prevent the hydrolysis of immunoglobulins

30
Q

Colostrum contains what minerals more than
normal milk

A

Colostrum contains more Mg, Ca and P than
normal milk

31
Q

Mg has a laxative effect, which helps to remove what in calves

A

the meconium

32
Q

What vitamins are necessary for the calves during the first hours of life, but their transport through the placenta is blocked

A

Vitamins A and E

Thus, calves have practically no reserves of
these vitamins at birth. Therefore, the colostrum must be rich in these vitamins.
Depends on dry cow feeding!

33
Q

Immunoglobulins are absorbed into the calves blood when?

A

1…3 hours after the first drink

▪ after 6 h, absorption is reduced by 50%

34
Q

48 hours after birth the concentrations of Ig in
the blood must be

A

> 10 g/l

35
Q

Milk composition normalises ? days after calving

A

Milk composition normalises 4…5 days after
calving

36
Q

Ruminal papillae develop better if what is fed

A

Ruminal papillae develop better if starchy
concentrates are fed, rather than if hay is fed

37
Q

Propionic acid (grains) promote development of
rumen papillae more than

A

acetic acid (roughage)

Butyric and lactic acids promote development of
rumen papillae even more, but they contribute to
acidosis (incl. metabolic).

38
Q

Lactic and butyric acids are metabolised partly
in the

A

rumen wall and provide energy for rumen
epithelial cells

39
Q

Hay and other fibre-rich feeds (dry silage) help
to develop (3)

A

rumen motility, stimulate saliva production and foster ruminal microflora formation

40
Q

Whole-milk contains in what % protein and
fat in DM?

A

25-27% protein and
29-32% fat DM

41
Q

Milk replacer should contain what % protein and
fat in DM?

A

➢20-24% protein of which at least 30-35% is casein
proteins, and

➢18-20% fat

42
Q

Unfortunately, traditional milk replacer doesn’t
contain enough

A

protein to support tissue growth

Due to this concentrate (starter) feed is essential,
start with this instantly after colostrum period.

High amount (> 10 litre) of milk-based feeds reduces
starter feed intakes.

43
Q

Today’s Holstein calf’s energy and protein
requirements are neither met by whole
milk nor milk replacer so this means

A

Good starter feed is very important!

44
Q

Starter feed should contain in DM: metabolisable energy ? MJ

A

13 MJ

– crude protein 19%
– crude fat 4%
– neutral detergent fibre 17%
– calcium 0,8%
– phosphorous 0,4%

45
Q

When to wean calves?

A

2…2,5 month of age

Concentrate intake ≥ 1.5 kg
– at least 1% of their body weight

46
Q

What weight to wean calves at?

A

≥ 85 kg

Chest circumference ≥ 95 cm
Concentrate intake ≥ 1.5 kg
– at least 1% of their body weight

47
Q

Feeding of heifers.

during the first year of growth the ration
protein content must be

A

higher,
then the heifer will not get fat in the second year of growth too

48
Q

Unfortunately, as body protein content
increases also does the

A

body’s fat content, but with feeding it is possible to affect the body’s fat and protein ratio

49
Q

Puberty depends on the growth rate. Usually
at about what age

A

9 months

thus, puberty is determined by body weight,
not age

50
Q

heifers will start to regularly come into heat
when their body weight is ca’

A

275kg (46% of adult body weight)

51
Q

Growth rate before puberty must be?
And after?

A

before puberty, faster, about 900 g per day

after puberty this must be slower,
about 700 g per day

52
Q

Age at first insemination depends on

A

growth rate, recommended at weight ca’ 380kg
(at age ca’ 14 month)

53
Q

Animal growth rate after insemination must be

A

300g per day without increment of gestation
tissues

54
Q

heifers’ optimal age at first calving is

A

24 months

55
Q

Udder growth and development during the heifer
rearing period largely determines

A

the cow’s later ability to produce milk and lactation persistence

56
Q

Energy level in the ration affects what 2 factors involved in heifer development

A

secretion of hormones and udder development

– if the ration energy content is low the development
of the udder glandular tissue will be delayed

– and in contrast, if the ration energy content is
high the glandular tissue of the udder will become overfat, especially when heifers are overfed during puberty

57
Q

In the first month of life calves’ digestion tract is comparable …

A. to monogastric animals
B. to ruminant animals
C. partly to monogastric animals

A

C. partly to monogastric animals

58
Q

At what time should colostrum be fed after birth?

A. This is not important
B. During first three hours
C. From 3 to 6 hours

A

B. During first three hours

59
Q

For proper forestomach development:

A. hay is essential and starter feed is
recommended
B. starter feed is essential and hay is
recommended
C. milk feed is essential and starter feed
together with hay are recommended

A

B. starter feed is essential and hay is
recommended

60
Q

Which period in the heifer’s life is most critical from an economic point of view?

A. From weaning to 9 months of age
B. From 9 to 15 months of age
C. From 16 to 23 months of age
D. Last month of pregnancy

A

A. From weaning to 9 months of age

61
Q

The daily growth rate of heifers after puberty must be either…?

A. Greater than before puberty
B. Less than before puberty

A

B. Less than before puberty

62
Q

When is the best time to inseminate heifers?

A. 9th month of life
B. 14th month of life
C. about 275 kg in weight
D. about 380 kg in weight

A

D. about 380 kg in weight

Animal nutrition (19 decks)

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