The decline in Zoetis shares is directly attributed to the mixed Q4 earnings report and the future guidance provided by the company. Mixed earnings typically indicate that while some aspects of the company's performance met or exceeded expectations, others fell short, leading to uncertainty among investors. The issuance of 2024 guidance further influences investor sentiment as it provides insight into the company's future expectations and growth prospects. Given that the guidance has contributed to a decrease in stock price, it suggests that the outlook may not have met investor expectations or that the market had anticipated more optimistic projections.