Jorja Robertson (13), of Wyndham, was second, after placing third last year.
Samantha won the Southern Rural Life trophy and $100, while Jorja received $50.
The contest encourages young people to enter the herdsperson competitions in A&P association shows at Wyndham, Gore and Winton.
Competitors were tested on how they led the animal, their knowledge of cattle, history of the breed, dam, sire, Tb status of the herd and the animal itself. The results were announced at the Gore A&P Show on February 1.
Samantha showed Lilliesleaf Boepeep 930 while JorJa showed Duncraigen Lydia 103.
Convener Rob Hall said the competition standard was good with strong novice and junior groups.
A South Otago High School pupil, Samantha said she enjoyed entering the competitions.
''I like being around animals and it's just fun. You need to know about the animal and the breed in general and what it is good for.
She has know Boepeep since she was a calf and as familiar with everything about her.