Cassava in Lactating Sow Diets: I. Effects on Milk Composition and Quality

The effect on sow milk of variable levels of cassava in lactating sow diets was analyzed in an attempt to explain the beneficial effects reported by producers of including cassava as a basal feed. Twenty crossbred lactating sows were randomly assigned to five dietary treatments. The treatments were: i) broken rice (BR) as the basal feed (BR100), ii) 50% of BR replaced with cassava chip meal (CCM) (CM50), iii) 75% of BR replaced with CCM (CM75), iv) CCM as the basal feed (CM100), and v) dried boiled cassava chips (CCB) as the basal feed (CB100). The hydrocyanide (HCN) content of CCB was reduced to be intermediate between HCN in the no cassava (BR100) and the 50% cassava (CB50) diets. Hydrocyanide was 0.54, 3.24, 4.41, 5.43 and 1.77 ppm in the BR100, CM50, CM75, CM100 and CB100 diets, respectively. Increasing cassava did not affect feed intake (p>0.05), but increased HCN intake (p<0.01). Milk composition was analyzed for protein, fat, lactose, solids not fat (SNF) and total solids (TS). Milk quality was analyzed for total microbes, coliform bacteria, thiocyanate ($SCN^-$), lactoperoxidase (LPO), and glutathione peroxidase (GPx) activity. At farrowing, sow milk composition was not affected by experimental diets (p>0.05), but milk $SCN^-$ increased as the intake of HCN increased in sows diets (p<0.01), $r^2$ = 0.96. At mid-lactation (day 14), milk composition was not affected (p>0.05). The milk quality levels of $SCN^-$ were 9.4, 10.3, 10.5, 11.6 and 9.1 ppm for the BR100, CM50, CM75, CM100 and CB100 diets, respectively (p = 0.01). The LPO contents were 16.41, 42.13, 51.42, 53.94 and 22.81 unit/L, respectively (p = 0.03). There was no GPx activity found in sow milk. When BR was replaced with cassava meal, total microbes and coliforms were reduced 78% and 87%, respectively, by the influences of HCN. The reported beneficial effects of cassava chip meal as a basal feed in lactating sow diets is manifested by improved performance of suckling pigs. This is due to beneficial, non-toxic levels of HCN in the diets. Besides passing HCN to suckling pigs in the form of $SCN^-$, sow milk may also benefit suckling pigs with the observed (day 14) increase in lactoperoxidase content and reduction in coliform bacteria.