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465 Nutrition > Dairy 1 > Flashcards

Dairy 1 Flashcards

**emphasized in class*** Covers material up to, but not including, dry period.

1
Q

top 2 provinces for dairy production

A

QB, ON

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2
Q

primary goal of any nutrition program is

A

formulate diets that meet the nutrient requirements of animal

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3
Q

what do we need to know to formulate balanced diets, 4 things

A

environment of animal, nutrient requirements, DMI, feed ingredient composition

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4
Q

average production per cow in Canada is

A

10,675 L per lactation (this is dry period of 60 days and then lactation of 305 days)

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5
Q

what 3 physiological processes contribute to energy and protein pool

A

internal digestibility, rumen fermentation

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6
Q

what is energy and protein pool used for, 5 things

A

maintenance,ce pregnancy, lactation, growth, reserves

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7
Q

what is gross energy (GE)

A

the total amount of chemical energy in the diet consumed

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8
Q

what is digestible energy (DE)

A

the amount of energy in the feed minus the amount of energy lost in the feces

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9
Q

what is metabolizable energy (ME)

A

the amount of energy in the feed minus the energy lost in the feces, urine, and gaseous (methane) loss

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10
Q

what is net energy (NE)

A

amount of energy in feed minus energy lost in feces, urine, gases, heat production; can be thought of as net energy for maintenance (NEm) and net energy for production (NEp, which is equal to RE)

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11
Q

what is first limiting factor concept (Sprengel-Liebig law of minimum)

A

growth is controlled not by the total amount of resources available, but by the scarcest resource.

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12
Q

what is retained energy (RE)

A

Retained energy (RE) is defined as the energy stored in body tissues or secretions, including feathers and eggs.

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13
Q

what forage quality do dairy production systems need

A

high quality

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14
Q

how do dairy calves acquire passive immunity and what is the cutoff for failure of passive transfer

A

colostrum, target is 10 mg/mL in calf serum IgG (remember in beef calves the cutoff is 24 mg/mL IgG)

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15
Q

compared to dairy cows, dairy heifers have higher or lower IgG content of colostrum

A

lower

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16
Q

tell me about colostrum composition

A

contains essential nutrients, antibodies, hormones, growth factors; first 2-3 weeks of life critical, composition changes to milk rapidly, should contain minimum 50 mg/mL IgG

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17
Q

what are 5 negative outcomes of failure of passive transfer

A

higher pre-weaning morbidity and mortality (4x increase in death rate), decreased weaning weight, decrease ADG to 180d, decreased milk and fat production at first lactation, delayed time to calving

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18
Q

considering that IgG absorption declines rapidly after first, what do we need to ensure for calves

A

need to feed calves colostrum before 6h to achieve serum IgG levels > 10 mg/mL (because IgG absorption declines rapidly in first 4 milkings and IgG absorption declines rapidly after birth)

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19
Q

how much IgG does a calf need to consume to achieve at least 10 mg/mL in serum?

A

depends on weight of calf, but 80-100 GRAMS IgG

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20
Q

you have a calf 40 kg weight. how much colostrum in L is required if your colostrum contains 50 g/L IgG?

A

plasma volume is 9% of blood, minimum plasma concentration is 10g/L, apparent efficiency of absorption is 35%.
Plasma volume = 40 kg x 0.09 = 3.6 L
Required IgG = 3.6 L x 10 g/L / 0.35 = 103 g
Required amount to feed = 103 g / 50g/L = 2.1 L
(note that the max you could give a Holstein calf at a single feeding after birth is 3.8L)

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21
Q

two methods to measure colostrum quality?

A

colostrometer (density) or optical refractometer

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22
Q

what is the minimum IgG level of colostrum

A

50 mg/mL IgG

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23
Q

calves are born with low energy reserves. what two immediate sources of energy are needed to maintain body temperature?

A

fat and lactose

24
Q

what has the higher kcal/g, colostrum or milk

A

colostrum (1.16 kcal/g vs 0.69 kcal/g)

25
Q

increasing the quantity of colostrum fed during the first 12h after birth is associated with: increased or decreased mortality

A

decreased mortality

26
Q

if a cow’s colostrum is not good, two options to ensure adequate colostrum are

A

colostrum banks (store frozen 1 year, reheat in 50 degrees C water bath) or colostrum substitutes (not as good, but there are colostrum replacers, from cows at selected herds, cheese whey, bovine serum)

27
Q

a young calf is functionally a

A

non-ruminant

28
Q

after receiving ______ and ______ for first few days of life, calves are fed either ______ or ________ until weaning (types of milk)

A

colostrum and transition milk; milk or milk replacer

29
Q

nutritional requirements for calves are based on these 4 things

A

weight, growth, environment (temp and humidity) health (moderate infections increase energy need by 150-200%)

30
Q

what are 3 disadvantages of feeding ‘hospital’ milk to values

A

milk not suitable for shipping, poor quality (mastitis), antibiotic residue (these can inhibit healthy bacteria development)

31
Q

what is the risk of feeding raw milk to calves? what can producers do to combat this risk?

A

diseases eg. Johne’s, BVDV, Salmonella. can pasteurize to reduce risk

32
Q

____ vary in composition and quality; they consist of animal fats (or other fats), whey, vitamins, minerals, AA, RBC protein and plasma protein, blended with an emulsifier, reconstituted with water to achieve 12% DM; fed at 1% body weight on DM basis, about 10% of BW

A

milk replacer

33
Q

milk replacers can be classified as

A

all-milk protein or alternate protein

34
Q

which contains the most ME: whole milk, milk replacer, or starter feed

A

whole milk contains the most. (starter feed the least)

35
Q

when are B-complex vitamins necessary in calf diets

A

when giving milk-replacer diets, until rumen fermentation is active

36
Q

list vitamins and minerals dairy calves require

A

vitamins A, D, E; minerals Ca, P, Se, Zn, Cu, K, I, S, Co, Mg, Na, Cl, Fe, Mn

37
Q

why do dairy cows need free access to water

A

water is needed for growth and consumption of dry feed; free access maximized starter intakes

38
Q

when does the rumen start to develop? when is it fully developed

A

when calf eats dry feed. by 6-8 weeks

39
Q

when is weaning? what is the weight goal at weaning time?

A

4-8 weeks and the goal is to double the birth weight

40
Q

tell me about calf starter

A

should contain 20-22% CP, high quality protein is needed, soybean meal is a common protein choice, often coccidiostat added, to improve intake and palatability use high quality ingredients, textured grains, added flavour, intact pellets; offer at first week (probably won’t eat, but encourages them to eat it), continue giving until consuming 2 kg/day

41
Q

what promotes development of rumen mucosa and papillae

A

propionate and butyrate (concentrate is better for promoting development than hay, has more VFAs)

42
Q

what is a calf given in an accelerated calf feeding program?

A

milk replacer with higher protein concentration, fed about twice as much milk replacer per day

43
Q

give an advantage and a disadvantage of accelerated calf feeding program

A

high growth rates before weaning and reach breeding size earlier, but higher cost of production

44
Q

order the ADG from highest to lowest: calf fed with 10% whole milk (by BW), 10% milk replacer, 18% whole milk, 18% milk replacer

A

18% whole milk, 18% milk replacer, 10% whole milk, 10% milk replacer (ie. higher volume is better and whole milk is better)

45
Q

why do calves need extra energy during cold weather

A

satisfy increase in maintenance energy requirements (limited body reserves and insulation at birth)

46
Q

what is the objective of feeding heifers from weaning to breeding

A

feed heifers to attain a pre-selected or target weight at a given age to achieve optimum first lactation performance while controlling cost or rearing replacements

47
Q

what are 2 negative effects of excess energy intake on heifers

A

negative effect on mammary parenchyma (mammary development) and reduced first lactation milk production

48
Q

after weaning, heifers will continue eating starter ration and should be introduced _________

A

high quality hay

49
Q

what can be introduced to heifers to replace starter when calves are 4 months of age, eating 2 kg starter daily

A

grower ration (contains 16-18% CP and monensin)

50
Q

what is given to heifers at age 6 months

A

silage-based total mixed ration (TMR)

51
Q

order the following diet types given to heifers between weaning and breeding: silage-based TMR, starter, grower, hay, liquid diet (based on the age they are first given, note there are overlaps)

A

liquid diet, starter, hay, grower, silage-based TMR

52
Q

what is mature shrunk body weight (MSBW)

A

weight of a cow after she delivers her third calf, following an overnight fast without feed or water

53
Q

give target body weights: for first bred target BW, for first post-calving target BW? (bonus, give the second and third post-calving target BWs)

A

55% mean shrunk body weight (MSBW), 82% MSBW. (bonus: 92% MSBW, 100% MSBW)

54
Q

your target MSBW is 700 kg. what is your target weight at first breeding? what is your target weight after third calving?

A

385 kg (target is 55% of MSBW). 700 kg (100% MSBW)

55
Q

the phenotypic and genetic trends for stature in Holstein calves have been ______ over the last several decades

A

increasing

56
Q

during the first two thirds of pregnancy, nutrient requirements of Holstein heifers are needed for ________ and ________, so are overall ___ compared to last third of pregnancy

A

maintenance and continued growth, overall lower

57
Q

during last rimester of pregnancy, nutrient requirements increase significantly due to rapid growth of _____ and ______

A

fetus and associated tissues

465 Nutrition (4 decks)

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