THE ROLE OF NUTRITION IN BREEDING The relationship between nutrition management and reproductive efficiency is key in dog breeding. experts advise breeders to practice proper nutrition management for reproducing bitches before mating, as a bitch should be in her best physical condition to help ensure a success- ful pregnancy and ease whelping her litter. Inadequate nutrition management, either deficiencies or excesses, may have a detrimental effect in pregnancy. They also have been shown to have negative effects on fertilization rate and number of fetuses. “It is important to feed reproducing bitches a highly digestible food that has at least 24 to 26 percent protein
Ideal nutrition for reproducing bitches is provided through a complete and balanced all life stages or puppy food, such as Purina Pro Plan SPORT Perform- ance 30/20 Formula, Purina Pro Plan Active 27/17 Formula or Purina Pro Plan Puppy food.
and at least 16 percent fat,” says Arleigh Reynolds, DVM, PhD, DACVN, Purina Senior Research Nutri- tionist, a board-certified veterinary nutritionist. “A complete and balanced food that is approved for all life stages or a puppy food that has nutrients to support females through growth and development will provide the nutrition needed during pregnancy and whelping. “If you switch from a lower protein and fat maintenance diet prior to breeding, there is a lag time of two to three months to get the full benefit of the diet. Besides the nutritional benefits of feeding a higher protein and fat food year-round, you can adjust the amount of food fed based on a dog’s body condition and metabolic energy needs.”
The fertile period occurs during estrus. Before estrus is proestrus, on average a nine-day signal of the start of the heat cycle. During proestrus, the bitch has a blood-tinged vaginal discharge, and the vulva is enlarged and swollen. As estrus begins, the bloody discharge diminishes, changing to pink or straw-colored and eventually becoming watery, though the vulva remains swollen. “The luetenizing hormone surge happens at the end of proestrus, and then estrus occurs for seven to nine days,” Dr. Lopate says. “The fertile period is the last four to five days of estrus.” Although a bitch is not typically receptive to breed- ing during proestrus, this changes during estrus. Her receptive, passive behavior during estrus encourages males to mate. Receptive behavior, however, is not a rule of thumb on when to breed all bitches. “Breeding based on receptive behavior or a set day of the cycle may result in breeding outside the bitch’s fertile period,” Dr. Lopate says. “It also may result in decreased litter size or failure to conceive. Receptive behavior is a result of the change in the estrogen to progesterone ratio and doesn’t always correlate with ovulation. “At the very end of estrus, or day one of diestrus, the cervix will close to sperm, so natural breeding or vaginal artificial insemination will not result in pregnancy,” Dr. Lopate says. “However, surgical arti- ficial insemination or transcervical insemination in which the sperm goes directly into the uterus by- passing the cervix will allow eggs to be fertilized for another two to three days.”
If a bitch is successfully bred, pregnancy occurs during the two-month diestrus stage. Whelping occurs around 64 to 66 days after the lutenizing hormone surge. The anestrus stage of reproduction, with no significant hormonal activity, follows diestrus. “The period of anestrus is important for the uterine epithelium to recover from the prolonged hormone exposure that occurs during estrus and diestrus,” Dr. Lopate says. “If this period is too short, the endo- metrium, or lining of the uterus, may not be compatible with embryo survival.” Some dogs have shorter interestrous intervals, the period from ovulation to ovulation, than is considered normal, though it does not hinder their reproduc- tive ability. “A few breeds, such as Akitas, Basset Hounds, Cocker Spaniels, Labrador Retrievers and Rottweilers, tend to have shorter interestrous intervals with normal fertility,” Dr. Lopate says. “Some breeds, such as Basenjis and Tibetan Mastiffs, cycle only one time a year. “We know that some bitches can conceive with a short interestrous interval, but others cannot. If the interestrous interval is under four months, less than 30 percent of bitches will conceive, yet if the inter- val is over five months, over 70 percent will conceive. In some cases, a short interestrous interval can be treated by medications to suppress estrus and pro- vide a normal interval.” Recognizing the signs of a heat cycle and under- standing the stages of the female reproductive cycle can help improve breeding management. Importantly, it can help you achieve successful conception and produce healthy litters of puppies.
11
Made with FlippingBook Learn more on our blog