Floss, Jeanette L.

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Pets and Companion Animals AGRICULTURAL 'MU Guide PUBLISHED BY UNIVERSITY EXTENSION, UNIVERSITY OF MISSOURI-COLUMBIA Reproduc'live Management of the Brood Bitch Jeanette L. Floss, D.V.M., M.S. College of Veterinary Medicine All dogs, male and female, that are to be housed heats is seven months. Heats may occur any time of in a breeding colony should receive a nutritionally the year and last an average of nine days (range 3 to balanced diet and annual vaccinations for distemper, 21 days). Besenji bitches are an exception and are in hepatitis, leptospirosis, parainfluenza and par­ heat only once each year, usually in the fall vovirus. Annual or three-year rabies vaccinations also The reproductive cycle in the bitch has four phas­should be maintained in accordance with local es that must be recognized to ensure proper breeding municipal regulations. management. These phases are influenced by hor­The dogs should test negatively for Brucellosis mones, which are responsible for the changes in the before being presented for breeding. Brucellosis is an reproductive tract and behavior in the bitch. infectious disease that may cause infertility in males Estrus is preceded by a nine-day period called and females as well as the abortion of litters around proestrus (range 0 to 17 days) in which the reproduc­45 to 55 days of pregnancy. There is no effective tive organs are being prepared for mating and con­treatment for this disease and no vaccine. Animals ception. This period is dominated by increasing levels tltat test positively should be removed from the of the hormone estradiol, which causes swelling of breeding colony. the vulva. A blood-tinged discharge is often seen at After a bitch reaches puberty between six and 24 this time. This discharge results from the action of months of age, she will be sexually receptive (in heat estradiol on the vessels of the uterus allowing blood or estrus) twice a year. The average period between to leak into the uterus. 30 E ...... ..Ol .sc: !? ~ .. W II.. 10 ANESTRUS I PROESTRUS I Esmus : DIESTRUS (METESTRUS) (variabl6 I6ngth) I 11 ~ 9 days : il - 9 days I (-2 months) .rang. = 0 fl) 17 days range ~ 310 21 daysj I I I I I I I I I I 50 I	 I I	 I E40 ......I I	 Ol J	 .E. JO 20 ~ 10 Progesterone I i -6 i i .3 ' ·10 -9 -8 -7 -6 -5 -4 ·3 -111 '.1'5 I I WEEKS I DAYS WEEKS I reclptive to mall _>_~~ superficial epithelial c.lIs Figure 1. Hormonal changes and reproductive events of the cycling bitch (adapted trom Olson and Husted, 1986, p.466). $.50	 G 9922 Printed with Soy Ink Archive version -- Seextension.missuri.eduFigure 2. Materials for collecting vaginal cytology samples are shown with sequentially labelled slides that identify the bitch and the dates of collection. The male dog may be attracted during proestrus, but the female usually will not permit him to breed. Late in proestrus a second hormone, progesterone, begins to increase while estradiol begins to decline. The combination of these two events is responsible for the bitch demonstrating receptivity to the male. She will permit him to mount, will deviate her tail and permit breeding. Decreased swelling of the vulva, cessation of the bloody discharge and acceptance of the male are char­acteristics of estrus (heat). Following estrus, the bitch eJters diestrus. The beginning of this phase is charac­terized by the refusal of the male. Progesterone will remain elevated during diestrus in the pregnant or non-pregnant bitch for almost 60 days. Diestrus is followed by a period of sexual inac­tivity (anestrus). The length of this cycle phase varies from one female to the next but usually lasts for several months. Many bitches will not fit into the "average" cycle (Figure 1). Therefore, proper management of the individ ual brood bitch is required to ensure a fertile mating and the delivery of a litter of pups. Sexual behavior differs greatly between bitches and by itself is not a reliable means of monitoring cycles. Greater accuracy in the timing of breeding can be achieved by combining behaviorial observations with daily vaginal cytologies and measurements of serum progesterone levels. Monitoring vaginal cytology and serum proges­terone levels should begin after the first day of proestrus. The vaginal lining changes in response to estradiol levels and the cell types presented are char­acteristic for the different stages of the reprod uctive cycle. During proestrus and early estrus, the number of layers of cells increases as much as tenfold and the most superficial cells are altered to resemble those much like the outer layer of skin. These changes are necessary to protect the reproductive tract during mating. FIgure 3a. Cytology sample collection. The speculum is intro­duced into the vaginal canal. Late in estrus with the decline in estradiol levels, the vaginal lining quickly returns to normal. Progesterone levels are low during proestrus. Late in proestrus, serum progesterone begins to increase. Maximum fertility occurs between four and six days following this initial increase. When the bitch enters proestrus, she should be presented to a veterinarian for an initial examination. At this time, the first of several sequential samples can be collected for vaginal cytology and an initial serum progesterone level can be established. The materials required to collect daily vaginal cytology samples can be obtained from a veterinarian and include: clean microscope slides, glass or plastic vagi­nal speculum and cotton swabs (Figure 2). The technique for collecting these cytology sam­ples should be demonstrated by a veterinarian before it is attempted at the breeding kennel. A clean glass microscope slide with one frosted end should be labelled in pencil with the name of the bitch and the date of the sample. The speculum with a cotton swab is introduced into the vaginal canal (Figure 3a). The swab is advanced through the speculum and lightly twisted one to two full turns in one direction and withdrawn (Figure 3b). The speculum should be cleaned and disinfect­ed after each use. The swab is then gently rolled across the prepared microscope slide several times (Figure 4) and allowed to dry. The slides may be held in this manner or may be fixed by dipping in methanol and again allowed to dry. Every second or third day, these slides are returned to the veterinari­an for staining and interpretation. Figures Sa and 5b demonstrate slides obtained during estrus and the first day of diestrus. Several commercial kits for measuring serum progesterone levels are available for veterinary use. Serum samples should be collected daily from the onset of proestrus until the initial rise is detected. Each bitch should be exposed to a male only when Page 2 G 9922 Figure 3b. The cotton swab is advanced and gently twisted. -the vaginal cytology demonstrates she is in estrus. Cytologic estrus and elevated serum progesterone levels correlate with increased conception rates. Additional breedings should take place at three­to four-day intervals as long as the vaginal cytology samples indicate the bitch is still in heat. When the cytology sample indicates that diestrus has begun, breeding should cease. If she becomes pregnant, the bitch should be expected to whelp 56 to 58 days from the first day of diestrus. " References Holst, PA. Vaginal Cytology in the Bitch. In Current Therapy in Theriogenology 2nd ed (986). D. Morrow (ed). W.B. Saunders Co. Philadelphia. p. 457-462. Olson, PN and PW Husted. Breeding Management for Optimal Reproductive Efficiency in the Bitch and Stud Dog. In Current Therapy in Theriogenology 2nd ed (986). D. Morrow (ed). W.B. Saunders Co. Philadelphia. p. 463-466. Olson, PN and TM Nett. Reproductive Endocrinology and Physiology of the Bitch. In Current Therapy in Theriogenology 2nd ed (1986). D. Morrow (ed). W.B. Saunders Co. Philadelphia. p. 453-457. Figure 4. Gently roll cotton swab across clean microscope slide at least two or three times. Figure Sa. A vaginal cytology slide obtained durIng estrus. .,• •"I. ." " • " AI WI .. t-•.. .. • tot. • .. -. Figure 5b. A vaginal cytology slide obtained on the first day of diestrus (magnification is less than In Sa). G 9922 Page 3 II • Issued in furtherance of Cooperative Extension Work Acts of May 8 and June 30,1914 ~)} University in cooperation with the United States Department of Agriculture. Ronald C. Powers,~Extension Interim Director, Cooperative Extension Service, University of Missouri and Lincoln UNIVERSITY OF MISSOURI University, Columbia, Missouri 65211 .• An equal opportunity institution. COLUMBIA Page 4 G 9922 New 12/92/5M 

Reproductive management of the brood bitch (1992)

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