The effect of chemical treatment and ultrasound processing (sonication) time on the ruminal degradability of palm date seeds (PDS) were evaluated. The PDS were either incubated with 4% NaOH at 50°C for 6 h (T1) or subjected to sonication(900 W, 20 kHz, 100% power level) for 5 (T2), 10 (T3), 20 (T4), and 30 (T5) min in a metal reactor containing 4% NaOH solution. The treated PDS were then recovered, freeze-dried and grounded. A 3 g sample of the untreated PDS (control) or treated PDS (T1 to T5) were placed in Dacron bags and then incubated in the rumen of a cannulated Holstein dairy cow fed a high forage-based diet (80:20; forage: concentrate). After 24 h of incubation, the Dacron bags were removed from the rumen, washed several times with cold water and then analyzed for DM, NDF, and ash to estimate ruminal degradability. Data were analyzed using one-way ANOVA model of JMP. The NDF_om and OM degradability for control PDS averaged 24.7 and 22.8%, respectively and both increased (P < 0.01) to 36.3 and 32.1%, respectively, with the T1 treatment. The NDF_om degradability of PDS also increased (P < 0.01) with sonication averaging 44.2, 46.5, 49.3 and 53.5% for the T2, T3, T4, and T5 treatments, respectively and was highest (P < 0.01) with the T4 and T5 treatments. Similarly, the OM degradability of PDS was also increased (P < 0.01) with sonication averaging 49.7, 48.9, 45.9, and 46.3% for the T2, T3, T4, and T5 treatments, respectively, and they were all higher (P < 0.01) than the control and T1 treatments. In conclusion, our results showed that treating PDS with 4% NaOH increased their ruminal degradability and subjecting PDS to sonication further improved their degradability in the rumen. Table 1 (Abstr. T139). The effect of treatments of the palm date seeds ruminal degradability

	Control	T1	T2	T3	T4	T5	MSE
NDFom, %	23.5d	33.6c	44.2b	46.5b	49.3ab	53.5a	2.65
OM, %	23.3c	29.5b	45.9a	46.3a	49.0a	49.7a	2.03

^a–dMeans with different letters within the same row are significantly different (P < 0.05).