Reference for Bekhorot 40:29

גדייה שילדה שלש בנות וכל בנותיה ילדו שלש שלש כולן נכנסות לדיר להתעשר

and each female gave birth to three,<span class="x" onmousemove="('comment',' At the end of their year. The offspring were females, but if they had been males, there would have been three firstlings and there could then be no tithing. All of them would have to be born between one Elul and the next, as the month of Elul is reckoned the New Year for animal tithing and those born before Elul cannot be tithed with those born after Elul; v. R.H. 2a.');">¹⁷</span>

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