Mineral Nutrition
Net sales of $184.2 million for the nine months ended March 31, 2023, decreased $5.9 million, or 3%, driven by a decrease in demand for trace minerals, partially offset by higher average selling prices. The increase in average selling prices is correlated to the movement of the underlying raw material costs.
Performance Products
Net sales of $55.5 million for the nine months ended March 31, 2023, decreased $0.8 million, or 1%, driven by decreased demand in personal care product ingredients and copper-related products, partially offset by higher average selling prices for these products.
Gross profit
Gross profit of $221.6 million for the nine months ended March 31, 2023, increased $14.6 million, or 7%, as compared to the nine months ended March 31, 2022. Gross margin increased 60 basis points to 30.7% of net sales for the nine months ended March 31, 2023, as compared to 30.1% for the nine months ended March 31, 2022.
Animal Health gross profit increased $16.4 million as a result of higher product demand, partially offset by higher raw material and logistics costs. Mineral Nutrition gross profit decreased $3.6 million, driven by lower sales volume and an increase in raw material costs. Performance Products gross profit increased $1.8 million due to higher sales, partially offset by higher raw material costs.
Selling, general and administrative expenses
SG&A of $173.5 million for the nine months ended March 31, 2023, increased $22.6 million, or 15%, as compared to the nine months ended March 31, 2022. SG&A for the nine months ended March 31, 2023, included $6.9 million of environmental remediation costs mostly related to the definitive settlement agreement related to the Omega Chemical Site. SG&A for the nine months ended March 31, 2022, included a $1.2 million gain on sale of investment and $0.3 million acquisition-related transaction costs. Excluding these items, SG&A increased $14.8 million, or 10%.
Animal Health SG&A increased $9.4 million primarily due to an increase in employee-related costs. Mineral Nutrition SG&A increased $0.3 million. Performance Products SG&A increased $1.1 million, mainly due to an increase in employee-related costs. Corporate expenses increased $4.0 million due to an increase in employee-related costs and strategic investments.
Interest expense, net
Interest expense, net of $10.8 million for the nine months ended March 31, 2023, increased $2.1 million, or 23%, as compared to the nine months ended March 31, 2022. Interest expense increased as a result of increased debt outstanding and higher floating interest rates on portions of debt outstanding, partially offset by increased interest income and a lower average fixed rate from our interest rate swap agreements.
Foreign currency (gains) losses, net
Foreign currency (gains) losses, net for the nine months ended March 31, 2023, amounted to net losses of $4.6 million, as compared to net gains of $12.6 million for the nine months ended March 31, 2022. Current period losses were driven by fluctuations in certain currencies relative to the U.S. dollar.
Provision for income taxes
The provision for income taxes was $11.5 million and $18.3 million for the nine months ended March 31, 2023 and 2022, respectively. The effective income tax rate was 35.3% and 30.5% for the nine months ended March 31, 2023 and 2022, respectively. The provision for income taxes for the nine months ended March 31, 2023, included a $0.9 million benefit related to exchange rate differences on intercompany dividends and a $0.2 million expense from changes in uncertain tax positions related to prior years. The