feeds
what are the disadvantages of using fibre in gestating sow diets
Large amounts of fecal materials
What are the advantages and disadvantages of floor feeding? and what category does it fall under
the least expensive option
fight for hierarchy, dominant sows have advantages in terms of feed intake and weight gain, subordinate sows fall behind in body condition, requires skillful management, cant individualize rations
competitive
What happens to embryos from day 0-15 of gestation
Fertilized embryos will elongate and migrate to find space in the uterus
embryo attaches to the uterus
maternal recognition of pregnancy will occur by day 11-12
if an insufficient number of embryos attach t the uterine wall, sow will return to heat
What does progesterone do
Crucial for embryo survival
Stimulates the secretion of histotroph
plays roles in conceptus nourishment, implantation, and placentation
What are the four aspects of successful farrowing
Duration less than 5 hours
reduced preweaning mortality
piglets receive colostrum
sow and piglets experience no complications
What are the important aa and vitamins and minerals for gestating sows
lysine
Ca and P - for growth, development of conceptus, and mammary glands
What are the advantages and disadvantages of trickle feeding? and what category does it fall under
shoulder length barriers separate the feeding troughs
feed slowly delivered over a period of 15-30 mins
sows remain at the feed space during feeding
competitive
What happens to embryos from day 13-30 of gestation
Placental begins to expand
pregnancy can be checked around day 30 using ultrasound
fluid filled sacs indicate that a litter is developing properly
confirm pregnancy before housing sows in group
How does maternal recognition of pregnancy happen? what substances are involved
Mechanism by which the conceptus prolongs the functional lifespan of the corpora lutea established after ovulation
swine conceptus signal their presence to the sow
interact with the maternal system to allow pregnancy to continue
Substances - estrogen, cytokines
What are the rates of preweaning mortality? and the major causes?
some farms = 25% of live born pigs dont survive until weaning
With good management, it should be possible to reduce preweaning mortality to less than 10%
causes - starvation, crushing, chilling, born weak, genetic defects, disease, savaging
What are the challenges with feeding group housed sow
maintaining body condition
hunger related aggression
potential for increased dietary energy cost due to aggresion
What are the advantages and disadvantages of non gated stalls feeding? and what category does it fall under
no back gate
divisions within the pen to separate feed drop areas
some protection
subordinate sows are able to defend their share of feed
longer stalls reduce aggression
competitive system
What happens to embryos from day 30-77 of gestation
beginning of organ development
bones begin calcifying at day 35-45
What are the functional characteristics of the epitheliochorial placenta
Low invasiveness - fetal tissue do not invade maternal blood supply
lower immunological conflict - maternal and fetal cells stay separated
requires large surface area - nutrient diffusion occurs across many layers
How can pre-weaning mortality be reduced
Supervised farrowing
increase piglet birth weight
increase piglet vigor
increase piglet competitiveness
reduce crushing and starvation loss
cross foster
reduce chilling loss
decrease incidence of disease
decrease savaging
reduce genetic defects
What are the different feed system options for sows
floor feeding
shoulder stalls
electronic sow feeder
free access stalls
What are the advantages and disadvantages of gated feeding stalls? and what category does it fall under
Sows housed in common area
different feeding spaces
gates close behind sows when feeding
a stall for each sow
cant know how much is consumed
non-competitive
What happens to embryos from day 77-90 of gestation
continued fetal growth
final placental expansion begins at day 77
visible mammary tissue expansion - colostrum and milk production
What are the signs of farrowing
Sow is restless and changes position often
Nest building
clear mammary secretion
milky secretion
respiration rate increases from 50 to 70-90 breaths per minute
increase in body temp from 38 to 39-40 degrees
abdominal contractions
what does oxytocin do
Produced in the hypothalamus
involved in parturition and lactation - important for milk letdown
contractions in the uterus muscles
What are the two categories feeding systems fall into
Competitive - more feed obtained by winning a fight
non-competitive = cant get more feed by winning a fight
What are the advantages and disadvantages of electronic sow feeding? and what category does it fall under
Computerized, group house and fed individually, measures feed intake, only one sow per time
Can take time to get into feeder
non-competitive
What happens to embryos from day 90-114 of gestation
Piglets are fully developed by day 90
development of mammary tissue is prioritized
milk secretion indicates imminence of farrowing
what are the physiological changes of farrowing
late stages of pregnancy - progesterone, LH, estrogen, cortisol, prolactin, relaxin and prostaglandins all interact to regulate parturition
approx 24-48 hours prior to beginning of parturition quick drop in pregesterone
concentration of prostaglandins peaks, oxytocin increases and begins to exhibit a cyclic activity
prolactin concentrations increase gradually
estrogens peak and then drop to basal levels
cortisol levels peak at farrowing and then decrease 24-36 hours post farrowing
What does prolactin do
Hormone which affects mammogenesis and lactogenesis in swine
secreted from the pituitary gland
surges prior to farrowing
regulates lactogenesis - initiates secretion of milk by the mammary glands