**Abstract**

Canine mastitis represents a major threat for both pups and nursing bitch. If left untreated, it can complicate with neonatal death, sepsis, and *mastitis gangrenosa*; for this reason quick and accurate diagnosis and treatment initiation are crucial health restoration. Even though mastitis is considered to be an emergency, most of the time it is overlooked. Henceforth, clinicians should be aware of the clinical importance of mastitis and that laboratory assays such as milk pH, cytology, and biochemistry (milk and serum) are of high utility. Furthermore, milk microbiology and susceptibility tests are still important since they bring additional information about the pathogenesis and the treatment possibilities.

**Keywords:** canine, mastitis, milk, cytology, pH, diagnostic

#### **1. Introduction**

Mastitis is an inflammation of the mammary glands. It can affect a segment or the entire mammary gland, one or more glands at the same time. Usually, the milk secretion is found modified, with a yellow-greenish to brown color, with a modified consistency, but there are also cases where the milk secretion is grossly unmodified. The ill bitch presents local signs of illness such as painful hot, red, engorged mammary glands, with or without general signs of disease like depression, anorexia, neglecting puppies, tacky mucous membranes, dehydration, delayed capillary refill time with sepsis, and even *mastitis gangrenosa*. For the litters, the main signs consist of failure to thrive and weight gain [1].

Mastitis has also been reported in *lactatio sine graviditate* (false pregnancy) bitches, as a result of milk retention and consistent licking of the activated mammary glands. Since this condition is evolving as clinical or subclinical, usually, in pseudocyesis dams, mastitis occurs because of an allergic reaction of the mammary gland to its own milk casein [1]. However, since every bitch undergoes *lactatio sine graviditate* [2], this condition should be addressed as an atavism and not a pathological behavior.

According to the pathogenesis and clinical signs, mastitis in bitches is classified as *mastitis acuta*, *mastitis gangrenosa*, galactostasis, *mammae* congestion, and subclinical mastitis. Furthermore, early recognition of galactostasis and *mammae* congestion is of great importance since, if not treated accordingly, it could lead to the development of mastitis.

*Mastitis acuta* cases are characterized by the presence of fever (40–41°C); hypertrophy of the mammary gland; extremely painful, hot, swollen mammary tissues, with a modified milk secretion (**Figures 1** and **2**); dehydration; anorexia; pyrexia; depression; and even sepsis in severe cases. Blood examination reveals neutrophilia with a left shift. Bacteriological examination of milk is positive in most cases [3].

*Mastitis gangrenosa* is described as the presence of severe local and systemic reaction characterized by fever (40–41°C), while affected mammary glands have a dark to purple color and are extremely painful, hot, and swollen; animals are dehydrated, anorectic, pyretic, and depressed and show signs of sepsis. Blood analysis reveals anemia, leukocytosis, and thrombocytopenia. Milk analysis shows an alkaline milk and presence of active inflammatory cells. Bacteriological examination of milk samples is also positive [3].

Subclinical mastitis is diagnosed based on clinical record, physical examination, and milk analysis (pH, cytology, and microbiology, among others). Usually, in subclinical mastitis cases, there is no visible alterations in mammary gland or milk secretion, while milk analysis indicates an alkaline pH and the increased number of

#### **Figure 1.** *A serous milk sample from a bitch suffering from mastitis acuta.*

**Figure 2.** *A mucopurulent milk secretin from a bitch diagnosed with mastitis acuta.*

*How Reliable Are Laboratory Test When Diagnosing Bitch Mastitis? DOI: http://dx.doi.org/10.5772/intechopen.86151*

somatic cell count (SCC; neutrophils, foamy cells, macrophages) (**Figures 3** and **4**). Bacteriological examinations are positive [3].

In galactostasis cases, there is no sign of infection, but the glandular tissue tends to get distended (**Figures 5** and **6**), warm, and painful. Small litters and absence of puppies will promote the buildup of a high pressure of milk into the undrained mammary glands, which will allow for the milk pH to become alkaline but will not change the milk chloride levels. Milk cytology will reveal the presence of increased count of eosinophils [3].

Bitches with *mammae congestion* can present local signs of mastitis including hardened, painful mammary glands and acidic milk pH. However, no inflammatory

**Figure 3.** *Clinical aspect of a healthy mammary gland.*

**Figure 4.** *Milk secretion, from a clinically healthy mammary gland.*

#### **Figure 5.**

*Distended mammary glands with galactostasis in a bitch that just weaned. Such glands are predisposed to develop retention mastitis.*

**Figure 6.** *Normal milk secretion from the same bitch.*

cells and phagocytosis are detected in milk smears. Discomfort during nursing is sometimes present. Bacteriological examination of milk samples is positive [3].
