Investigations into the puerperium of Beagle-breed female dogs

The present thesis focusses on the study of the puerperium of female dogs, with the general objective to increase available knowledge regarding the puerperium of that species and to elucidate the process of involution of the uterus and the mammary glands in female dogs. Specific objectives of the thesis were as follows: (i) a proposal of ‘reference’ values for haematological and blood biochemical parametres during the puerperium, (ii) the description of anatomical details and their progressive changes in the uterus and the mammary glands during the puerperium, (iii) the identification of time periods, during which the uterus and the mammary glands are more susceptible to infection, (iv) the identification of cells present in the uterine content and in the milk and (v) the study of sucking behaviour during lactation and the identification of potential risk factors for mammary infections.Initially (1st Chapter), the relevant literature is reviewed. The Chapter is subdivided into three Parts. In Part A, principles of anatomy of the reproductive system and of physiology of the puerperium of female dogs are briefly reviewed. In Part B, the literature on pathological conditions of female dogs during the puerperium (systemic post-partum pathological conditions, post-partum pathological conditions of the uterus, post-partum pathological conditions of the mammary glands) is reviewed. In Part C, the ovario-hysterectomy during the puerperium is presented.Materials and methods used are described in detail in the 2nd Chapter. In total, 12 primiparous Beagle-breed female dogs were used in the study. Animals whelped normally. Subsequently, all animals were monitored until the 84th day post-partum. The following examinations were carried out: (i) general clinical examination (female dogs and puppies), (ii) clinical examination of the genital system, (iii) ultrasonographic examination of the uterus and the ovaries, (iv) clinical examination of the mammary glands, (v) ultrasonographic examination of the mammary glands, (vi) measurement of haematological and blood biochemical parametres, (vii) measurement of blood serum progesterone concentration, (viii) bacteriological and cytological examination of vaginal swab samples, (ix) bacteriological examination and cytological examination of teat duct material and milk samples, (x) behavioural observations. Dogs were subjected to ovario-hysterectomy and partial mastectomy on each of 4th, 7th, 10th, 14th, 21st, 28th, 35th, 42nd, 56th, 70th and 84th day after whelping. Appropriate tissue samples were collected for detailed examinations and the following were studied: (i) gross appearance of the uterus and the ovaries, (ii) bacteriological and cytological examination of uterine content samples, (iii) histological, histometric and ultrastructural examination of uterus and ovary tissue samples, (iv) bacteriological examination of mammary parenchyma samples, (v) histological, histometric and ultrastructural examination of mammary parenchyma tissue samples. Standard clinical, paraclinical, laboratory, behavioural and data analysis techniques were employed. For the purposes of analysis of results of the study, the puerperium was divided into four stages: L1 included samples collected from D0 (i.e., day of whelping) to D7 (7 days after whelping) (n=59), L2 included samples collected from D8 to D21 (n=27), L3 included samples collected from D22 to D42 (n=18) and L4 included samples collected from D43 to D84 (n=18). Specifically for analysis of haematological and blood biochemical parametres, samples collected during pregnancy were also taken into account.The results of the study are presented in the 3rd Chapter and are summarised herebelow.•Animals were clinically healthy throughout the study.•A significant effect of the peri-parturient period (last week of pregnancy and first week of the puerperium) was observed for the following parametres, rendering proposed ‘reference’ values during that period as follows: haematocrit 24.1-35.3%, leucocyte counts 13,200-31,400 μL-1, thrombocyte counts 502,000-912,000 μL-1, haemoglobin concentration 7.7-10.6 g dL-1, mature neutrophil counts 8,500-25,200 μL-1, lymphocyte counts 2,200-7,500 μL-1, total protein concentration 4.3-6.4 g dL-1, albumin concentration 1.7-2.6 g dL-1 and C-reactive protein concentration 30.0-180.0 mg L-1. Other parametres (alkaline phosphatase activity, calcium-ion concentration and total calcium concentration) were significantly affected during the peri-parturient period, but remained within the established ‘reference’ values. Finally, other parametres (mean corpuscular haemoglobin concentration, fibrinogen concentration, mature neutrophils proportion, immature neutrophils counts and proportion, lymphocytes proportion, monocyte counts and proportion, eosinophil counts, basophil counts, globulin concentration, glucose concentration, magnesium concentration) were not affected.•Median value of blood serum progesterone concentration was 0.43 ng mL-1; it was higher in [L1+L2] compared to [L3+L4] (0.48 ng mL-1 versus 0.32 ng mL-1, P=0.013).•Vaginal discharge was observed in 58% of sampling occasions, continuously up to D21 and intermittently up to D77, in ‘scanty’ to ‘small’ amount. Median diametre of the body of the uterus, as estimated during palpation through the abdominal wall, was progressively reduced during the puerperium; it was estimated at ~3.0 cm on D0 to <1.0 cm on D28 and subsequently (P=0.01). Median value of dimensions of the vulva during the puerperium were as follows: total horizontal width × total vertical length = 2.7 cm × 3.4 cm; median value of distance from anus to upper vulval commisure was 8.0 cm. Dimensions of the external genitalia progressively decreased during the study.•Up to D21, the uterus appeared with a heterogeneous echopattern; it was easy to recognize and image the organ, because width of the uterine horns was estimated to be ≥1.0 cm. After that day, it was more difficult to image it, as their width was progressively decreasing and, on D70, was estimated to be 0.6 to 0.7 cm (P<0.001). In longitudinal images, the uterus appeared consistently cylindrical in shape. In transverse images taken up to D21, the sections of the organ appeared polygonal to compressed circular to circular; in transverse images taken after D21, they appeared consistently circular. There was evidence of a hypoechoic rim, with a more echogenic inner architecture. In some images, the anechoic lumen was barely visible, because of the more echogenic content, whilst in others, it was observed greatly contrasting to the hyperechoic endometrium. The placental sites appeared as granulated structures of medium echogenicity, with small anechoic areas. Initially, the uterine wall was imaged as a multi-layer structure, but, subsequently, number of layers imaged was reduced. Thickness of myometrium and endometrium was found to progressively decrease as the puerperium advanced (P<0.001), as was diametre of the lumen of uterine horns (P=0.003).•In total, 51 of 122 vaginal samples examined bacteriologically, yielded bacteria. Frequency of bacterial isolation from vaginal samples was 0.525 during L1, 0.333 during L2, 0.333 during L3 and 0.278 during L4 (P=0.094). Median time to first infection after whelping was 0.25 days. Estimated median duration of infection (all infections taken into account) was 5.25 days. Most of the organisms recovered were Escherichia coli and Trueperella (Arcanobacterium) pyogenes: 22 and 16, respectively, of the 55 isolates recovered.•In smears from swab samples from the anterior part of the vagina, the majority of cells observed were epithelial cells. Uterine epithelial cells, normal or degenerated, were observed characteristically clustered, whilst vaginal cells observed were primarily parabasal or small intermediate cells. Leucocytes were also observed in these smears; neutrophils predominated. Trophoblast-like cells were also evident in L1 and L2. There was a progressive increase in epithelial cell counting scores and progressive decrease in leucocyte counting scores observed during the puerperium (P<0.04). Cell counting scores for samples which had yielded bacteria were significantly higher for leucocytes (P=0.045), but not for for epithelial cell counting scores (P=0.383).•During the study, the mammary glands were soft and with homogeneous consistency. On D1, the mammary secretion was thick and yellowish, thereafter (occasionally on D2, but always on D4) becoming ‘milky’.•The mammary parenchyma showed, in general, a homogeneous consistency and medium echogenicity. As the puerperium advanced, a less homogeneous echopattern was seen and (compared to previous periods) lower echogenicity was recorded; increased amount of connective tissue was also evident in ultrasonograms during that period. Occasionally, it was possible to image different lobules within the same mammary gland, separated by connective interlobular tissue.•Frequency of bacterial isolation from teat ducts was 0.068 during L1, 0.130 during L2, 0.0 during L3 and 0.028 during L4; frequency of bacterial isolation from mammary glands was 0.091, 0.104, 0.122 and 0.017, respectively. There was a greater probability of bacterial isolation from Rc1 (right most caudal gland) than [Rc3 or Rc4] glands, as well as from Rc2 than Rc4 glands (P<0.02); there was also a greater probability of bacterial isolation from [Rc1+Rc2] than from [Rc3+Rc4] glands (P<0.001). Median time to first infection after whelping was significantly (P=0.044) shorter for Rc1 than for Rc2, Rc3 or Rc4 (median time: 3 days for Rc1, >7 days for Rc2, Rc3 or Rc4). Most of the organisms recovered were staphylococci: 14 of the 17 isolates (82%) from teat duct material and 45 of the 53 isolates (85%) from milk; Staphylococcus pseudintermedius was the most frequently recovered species (7 and 24 isolates, respectively).•Mean (median) Whiteside test (WST) score of bacteriological