Dairy 1 Flashcards
**emphasized in class*** Covers material up to, but not including, dry period.
top 2 provinces for dairy production
QB, ON
primary goal of any nutrition program is
formulate diets that meet the nutrient requirements of animal
what do we need to know to formulate balanced diets, 4 things
environment of animal, nutrient requirements, DMI, feed ingredient composition
average production per cow in Canada is
10,675 L per lactation (this is dry period of 60 days and then lactation of 305 days)
what 3 physiological processes contribute to energy and protein pool
internal digestibility, rumen fermentation
what is energy and protein pool used for, 5 things
maintenance,ce pregnancy, lactation, growth, reserves
what is gross energy (GE)
the total amount of chemical energy in the diet consumed
what is digestible energy (DE)
the amount of energy in the feed minus the amount of energy lost in the feces
what is metabolizable energy (ME)
the amount of energy in the feed minus the energy lost in the feces, urine, and gaseous (methane) loss
what is net energy (NE)
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)
what is first limiting factor concept (Sprengel-Liebig law of minimum)
growth is controlled not by the total amount of resources available, but by the scarcest resource.
what is retained energy (RE)
Retained energy (RE) is defined as the energy stored in body tissues or secretions, including feathers and eggs.
what forage quality do dairy production systems need
high quality
how do dairy calves acquire passive immunity and what is the cutoff for failure of passive transfer
colostrum, target is 10 mg/mL in calf serum IgG (remember in beef calves the cutoff is 24 mg/mL IgG)
compared to dairy cows, dairy heifers have higher or lower IgG content of colostrum
lower
tell me about colostrum composition
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
what are 5 negative outcomes of failure of passive transfer
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
considering that IgG absorption declines rapidly after first, what do we need to ensure for calves
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)
how much IgG does a calf need to consume to achieve at least 10 mg/mL in serum?
depends on weight of calf, but 80-100 GRAMS IgG
you have a calf 40 kg weight. how much colostrum in L is required if your colostrum contains 50 g/L IgG?
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)
two methods to measure colostrum quality?
colostrometer (density) or optical refractometer
what is the minimum IgG level of colostrum
50 mg/mL IgG
calves are born with low energy reserves. what two immediate sources of energy are needed to maintain body temperature?
fat and lactose
what has the higher kcal/g, colostrum or milk
colostrum (1.16 kcal/g vs 0.69 kcal/g)
increasing the quantity of colostrum fed during the first 12h after birth is associated with: increased or decreased mortality
decreased mortality
if a cow’s colostrum is not good, two options to ensure adequate colostrum are
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)
a young calf is functionally a
non-ruminant
after receiving ______ and ______ for first few days of life, calves are fed either ______ or ________ until weaning (types of milk)
colostrum and transition milk; milk or milk replacer
nutritional requirements for calves are based on these 4 things
weight, growth, environment (temp and humidity) health (moderate infections increase energy need by 150-200%)
what are 3 disadvantages of feeding ‘hospital’ milk to values
milk not suitable for shipping, poor quality (mastitis), antibiotic residue (these can inhibit healthy bacteria development)
what is the risk of feeding raw milk to calves? what can producers do to combat this risk?
diseases eg. Johne’s, BVDV, Salmonella. can pasteurize to reduce risk
____ 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
milk replacer
milk replacers can be classified as
all-milk protein or alternate protein
which contains the most ME: whole milk, milk replacer, or starter feed
whole milk contains the most. (starter feed the least)
when are B-complex vitamins necessary in calf diets
when giving milk-replacer diets, until rumen fermentation is active
list vitamins and minerals dairy calves require
vitamins A, D, E; minerals Ca, P, Se, Zn, Cu, K, I, S, Co, Mg, Na, Cl, Fe, Mn
why do dairy cows need free access to water
water is needed for growth and consumption of dry feed; free access maximized starter intakes
when does the rumen start to develop? when is it fully developed
when calf eats dry feed. by 6-8 weeks
when is weaning? what is the weight goal at weaning time?
4-8 weeks and the goal is to double the birth weight
tell me about calf starter
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
what promotes development of rumen mucosa and papillae
propionate and butyrate (concentrate is better for promoting development than hay, has more VFAs)
what is a calf given in an accelerated calf feeding program?
milk replacer with higher protein concentration, fed about twice as much milk replacer per day
give an advantage and a disadvantage of accelerated calf feeding program
high growth rates before weaning and reach breeding size earlier, but higher cost of production
order the ADG from highest to lowest: calf fed with 10% whole milk (by BW), 10% milk replacer, 18% whole milk, 18% milk replacer
18% whole milk, 18% milk replacer, 10% whole milk, 10% milk replacer (ie. higher volume is better and whole milk is better)
why do calves need extra energy during cold weather
satisfy increase in maintenance energy requirements (limited body reserves and insulation at birth)
what is the objective of feeding heifers from weaning to breeding
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
what are 2 negative effects of excess energy intake on heifers
negative effect on mammary parenchyma (mammary development) and reduced first lactation milk production
after weaning, heifers will continue eating starter ration and should be introduced _________
high quality hay
what can be introduced to heifers to replace starter when calves are 4 months of age, eating 2 kg starter daily
grower ration (contains 16-18% CP and monensin)
what is given to heifers at age 6 months
silage-based total mixed ration (TMR)
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)
liquid diet, starter, hay, grower, silage-based TMR
what is mature shrunk body weight (MSBW)
weight of a cow after she delivers her third calf, following an overnight fast without feed or water
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)
55% mean shrunk body weight (MSBW), 82% MSBW. (bonus: 92% MSBW, 100% MSBW)
your target MSBW is 700 kg. what is your target weight at first breeding? what is your target weight after third calving?
385 kg (target is 55% of MSBW). 700 kg (100% MSBW)
the phenotypic and genetic trends for stature in Holstein calves have been ______ over the last several decades
increasing
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
maintenance and continued growth, overall lower
during last rimester of pregnancy, nutrient requirements increase significantly due to rapid growth of _____ and ______
fetus and associated tissues
