For loving owners and dog breeders, it is crucial to nurse healthy birth of puppies successfully. The key to having beautiful puppies is to have enough and proper mammary glands. Professional breeders are also interested in how many nipples a dog has regarding the subsequent selection of puppies for exhibitions.
The mammary glands in dogs: structure and development
The mammary gland of a dog includes a connective tissue stroma and parenchyma - the lobes (numbering from 6 to 12), consisting of alveoli and tubes of glandular tissue. The alveoli give rise to diverticular tubes that connect into the milk ducts. The end of the mammary gland is a cone-shaped nipple that is not covered with hair.
The mammary glands are supplied with fresh blood by the inguinal and pectoral arteries and by the suprailiac, abdominal and iliac arteries. The outflow of lymph is regulated by lymph nodes located in the axillary, inguinal and thoracic regions of the female torso.
The milky secretion in the glands is formed when the nervous system, pituitary gland and other endocrine glands of the animal interact. During puberty and when nursing puppies, the dog's mammary glands are influenced by the ovaries: the increased production of estrogens and progesterone causes the mammary glands to swell. In this case, estrogen promotes the formation of many milk ducts, while progesterone develops the alveoli.
Towards the end of pregnancy, the dog's mammary glands seem to swell. It is a layering of secretory tissue in which milk is produced. The nipples also increase in size and lengthen (sometimes twice as much). The swelling of the mammary glands persists for several months after lactation, but the papillae remain elongated. Milk production is triggered reflexively after the pups irritate the papilla: the sucking movements stimulate the pituitary gland to release the lactation hormone. Also, If the female is sterilized at a young age, breast development does not occur.
The first food for puppies comes from their mother's blood - the white liquid is almost sterile by filtering through the nipples. Mother dog's milk contains more fat and more digestible protein than cow's, but it has less milk sugar to meet puppies' needs (which is why regular milk can cause diarrhoea in puppies).
Feeding lasts for eighteen months to two months, and as the months go by, the mother dog reduces the number of feedings, and she increasingly leaves the pups to stretch and gain strength.
During the lactation period, the owner needs to keep her mammary glands clean by rinsing them periodically with warm soapy water and wiping them thoroughly. You should also pay attention to the condition of the hair on the abdomen of the lactating mother.
The standard number of nipples
So how many nipples is a dog supposed to have? Veterinarians and dog breeders reckon that female dogs usually have ten nipples each, arranged in pairs, so that's five pairs in total.
The flow of lymphatic fluid contributing to milk production runs towards the axillary and inguinal lymph nodes, with the first three nipple pairs running to the armpits and the last two to the groin. Mixed flows of lymph to both axillary and inguinal nodes have also been observed, usually between the third and fourth pairs of mammary glands.
Variations in the norm
In dogs, there are individual variations in the number and location of mammary glands that are within the normal range. Since they are multiparous animals, there can be 2 to 6 pairs of nipples, i.e. 4 to 12. Quite often, owners find that their dog has nine nipples.
The odd number of nipples is due to their non-parallel placement on the animal's body. There are also 'non-working' nipples that do not end in a milk outlet. These mammary glands are usually adjacent to the normal ones but do not affect pups' milk production and lactation. The milk ducts are not formed in them and will never develop.
Sometimes dogs have 'paired' nipples, which have one nipple but two heads - this is also normal. It can be troublesome for dog owners to check daily milk filling and lactation with a fuller one; otherwise, lactostasis can occur.
How the quantity affects
Some novice dog owners unreasonably fear that the number of nipples will affect the lactation of puppies. But this is far from the case: no matter how many nipples a dog has, it's filling the milk ducts with caloric milk that counts.
How well a female's mammary glands are doing can be judged by her pups' condition and behaviour: well-fed pups are lustrous, plump, fall asleep quickly after suckling and don't suffer from diarrhoea. If puppies are weak, squeaky and don't put on weight, it means the dog's nipples are not healthy:
- They don't produce enough milk.
- The babies have difficulty sucking.
- They have an inflammation of the mammary gland.
The owner's concern in such a case should be to carefully examine the mother for any traces of blood or pus in the milk.
The number of nipples in a lactating female dog is, to some extent, genetically determined. First of all, this relates to the breed parameters of the dog:
- Large breeds (Labradors, Dobermans, etc.) have 8 to 12 nipples (i.e. 4-6 pairs of mammary glands)
- Small breeds (Chihuahua, Pug, Dachshund, Yorkshire Terrier, etc.) often have 6-8 nipples, sometimes 7.
If a dog has an odd number of mammary glands (seven or nine), they may be genetically more prone to certain gynaecological diseases:
- Inflammation of the ovaries
Some vets advise that such dogs should not be allowed to mate but should be sterilized as early as possible.
It's essential for owners to know what's normal for their breed and not harmful to breastfeeding, and what's really worrying and why you should call your vet as soon as possible.
© 2021 Anjlee Yadav