Reproductive and parental behavior A.J. Zanella ANS 305

Objective To discuss reproductive behavior in domestic mammals

Pre-copulatory and copulatory behavior Courtship Motivational aspects Enhance sperm production Enhance fertilization Increase litter size (pigs) Copulatory responses Consummatory responses Most of the current information is on males Exception dogs and cats

Variability in sexual behavior Males Courtship is highly variable Licking & sniffing the female genitalia Nudging Vocalizations Copulation is less variable than courtship

Variability in sexual behavior Females Courtship (proceptive behavior) Mounting behavior (cows) Urination (mares & ewes) Seeking out & selecting males Copulatory behavior Receptive behavior Passive responses (?) Exceptions: cats & dogs

Domestic mammals (females) Cyclic nature Display no interest in males and will not be receptive outside the estrous period Olfactory, auditory and visual stimuli produced by females have “attractive” qualities to males Females display preferences for sexual partners Sows; ewes; bitches & female cats

Mate choice and timing of mating

The evolution of seasonal breeding Domestic species evolved in temperate climates Reduce risk of predation Avoid delivery at the times when resource are limited Domestication has altered seasonal reproductive behavior in several species

Species Estrous cycle Length Duration Dog Monoestrous 1 cycle/season (2x) 7-10 days Cat Seasonally 3 weeks 1-4 days polyestrous 7-10 days Horse Seasonally 3 weeks 5-6 days polyestrous Cattle Polyestrous 3 weeks 10-12 hours Sheep Seasonally 16-18 days 36 hours Goat Seasonally 3 weeks 12-24 hours Swine Polyestrous 3 weeks 2-3 days

Behavioral signs of estrus Sensory and motor activity Increase in general activity Ovulation in women (Morris & Udry, 1970) Increase in sensory acuity Neuronal “re-organization” Visual Olfactory Spatial memory

Behavior of estrus females towards males Proceptive behavior Females will seek males Standing behavior Vocalizations Urination Mares, sheep and goats

Female responses during copulation Limited data ? Copulation causes an increase in uterine motility Uterine motility follows nuzzling and mounting by a bull Female cats, 5 to 10 seconds post-intromission, becomes very aroused (eyes dilate, they may turn and hit the male)

Behavior of estrus females towards other females Agonistic interactions cows; pigs; mares Increase in vocalizations Attempts to mount other animals cows; bitches; sows Standing while mounted by other animals Cows (56 times over a 15 hours period) PRESENCE OF MALES MAY ELICIT MORE PRONOUNCED BEHAVIORAL RESPONSES

Sexual behavior of males Pre-copulatory behavior is highly variable Beef bulls have a more elaborated courtship display than dairy bulls Male broiler breeders (domestic fowl) are more aggressive towards females than commercial laying strain males (Millman et a,, 1999)

Sexual behavior of males Investigate the genitalia of the female Flehmen behavior may follow Play behavior (dogs) Mounting Attempt copulatory intromission by pelvic thrusting

Stallion

Bull

Boar

Ram

Goat

Olfactory stimuli Pheromones Vaginal secretions Urine Preputial gland Substance produced by one animal which conveys information to other individuals by olfactory means Vaginal secretions Urine Preputial gland Salivary glands

Pheromones Hamsters Dogs Pigs Dimethyl disulfide in vaginal secretions Methyl-p-hydrobenzoate in urine of bitches Pigs Androgenic steroids is saliva of boars

Detection of pheromones Olfactory system Volatile substances Vomeronasal organ Flehmen behavior: head elevation and curling of the upper lip. Non-volatile substances Primarily performed by males Females may show the behavior towards newborn animals or amniotic fluid.

Flehmen behavior Fluid is drawn from the oral cavity through the nasopalatine duct and to the posterior part of the vomeronasal organ.

Inclusive reproductive fitness Males may help close relatives (horses) Females may support sisters when they are not able to breed Wolf packs: only the dominant females have pups their female relatives help to look after the young

Sexual suppression Females Males Honey bees Some primates Naked mole rats Males Stallions

Monogamy Domestic dogs are the only domestic species that retain “some” indicative of monogamous behavior