Lambs rely on their teeth for proper nutrition and development. Understanding the stages of tooth development, from initial milk teeth to the permanent set, provides insights into a lamb’s growth. Observing these dental changes also offers a reliable way to estimate their age, which is helpful for various management practices.
Early Development: Lamb Milk Teeth
Lambs are born with a set of temporary incisors, milk teeth or deciduous teeth, on their lower jaw. While some lambs may have no teeth at birth, these eight temporary incisors usually emerge within a week and are fully erupted by two months of age. These teeth are smaller and sharper than their permanent counterparts. They enable young lambs to suckle and, as they grow, to begin grazing on forage.
The Process of Permanent Tooth Eruption
A natural transition occurs as lambs mature, involving the shedding of milk teeth and the eruption of permanent teeth. This process typically begins around 12 to 18 months of age with the emergence of the first pair of permanent incisors. Each subsequent year, another pair of permanent incisors erupts, starting from the center and moving outwards, until the lamb is approximately four years old. These physiological changes include the strengthening of the jaw structure, allowing for more robust chewing of tougher forage as the animal matures.
While the incisors are the most commonly observed for age determination, sheep also develop 24 molars, six on each side of the upper and lower jaw, which contribute to their chewing ability. The eruption of permanent teeth signifies a lamb’s increasing capacity to process a wider range of feedstuffs.
Aging Lambs Through Dental Examination
Estimating a lamb’s age can be achieved by examining its lower incisor teeth. This method involves observing the presence, absence, and wear patterns of both milk and permanent teeth. Lambs from birth to approximately one year of age will possess their full set of eight temporary milk teeth. These appear smaller and whiter than permanent teeth.
As a lamb approaches one year old, the central pair of milk incisors will be replaced by larger, permanent incisors. By around two years of age, the lamb will display two pairs of permanent incisors, and by three years, three pairs will be present. A sheep with all eight permanent incisors, typically achieved by four years of age, is considered to have a “full mouth.”
Beyond four years, age estimation becomes less precise, as teeth may show signs of wear, gapping, or even loss, becoming longer due to gum recession. Factors like diet and environment can influence tooth wear, making this method an estimation rather than an exact age determination.