Effect of lactation stage, parity and supplementary feeding with buffelgrass (Cenchrus ciliaris) and old man saltbush (Atriplex nummularia L.) on yield, composition, and microbial properties of camel milk produced in Tsabong

Abstract

The study involved two experiments. The first experiment of the study evaluated the effects of lactation stages (LS) and parity (PA) on the composition and properties of camel milk from 24 dromedary camels reared in Tsabong Camel Park, after which the second experiment was a feeding trial done to investigate the effect of supplementary feeding with either or both Cenchrus ciliaris and Atriplex nummularia, in order to evaluate their effect on the quality and quantity of Tsabong Dromedary camels’ milk. In the first experiment, a factorial design in CRD was used where lactating camels were randomised into three lactation stages (early, mid and late) each of which fell into each of the two parity stages (primiparous and multiparous). For the second, feeding experiment, twenty-four (24) ear-tagged multiparous camels in mid-lactation, were separately given the supplementary feed used as treatment (None supplemented, as a control group, Cenchrus ciliaris alone, Atriplex nummularia alone, Cenchrus ciliaris & Atriplex nummularia). In the first experiment, the highest levels of total solids (TS) (9.785±0.697%) were observed in primiparous in early lactation camels. Total fat (3.675±0.442%) was highest in primiparous camels in early lactation camels. Multiparous camels in mid-lactation camels had the highest protein (1.910±0.188%). primiparous in late lactation camels had the highest content of solids-not-fat (SNF) (6.330±0.313%). Milk from primiparous in early lactation camels contained the highest free fatty acids (FFA) (0.580±0.057g/L) and multiparous in mid lactations camels had the highest casein (1.718±0.104%). Primiparous camels in late lactation produced the highest level of lactose, (3.568±0.227%). While Primiparous camels in their early lactation produced the highest levels of galactose and glucose, (0.685±0.066%) and (0.363±0.042%), respectively. In the second experiment, supplementary feeding with all three treatments positively affected milk protein, 2 urea, and casein percentages. Also increased were milk components of fat, galactose, glucose, solids not fat (SNF), total solids (TS), as well as citric acid contents and density. Another improvement was found in daily milk yield being influenced greatly (P=0.0001) by the supplementary feeding with all three treatments, with the highest positive effect coming from supplementing with Atriplex nummularia. However, supplementary feed sources significantly reduced (P<0.05) free fatty acids (FFA) content as well as the freezing point of camel milk. The highest concentrations of fat, galactose, glucose, protein, and total solids were 4.222%, 0.878%, 0.372%, 3.143% and 11.762%, respectively, were detected on milk from camels supplemented with Atriplex nummularia alone. Supplementing with Cenchrus ciliaris alone produced milk with the highest SNF content (7.458%), whilst a combined feed (Cenchrus ciliaris and Atriplex nummularia) significantly produced milk with the highest milk casein (2.473%). All treatment feeds insignificantly (P>0.05) reduced concentrations of lactose. The results of the study show that the composition of camel milk produced in Tsabong, from free-ranging dromedary camels, under the existing and unimproved feeding conditions, was affected by parity and stage of lactation. Generally, supplementing Tsabong dromedary camels could greatly improve camel milk yield and quality during the dry season. Milk processors could target specific levels of desired components of camel milk, based on milk obtained from camels at specific stages of lactation and parities. Those components that were not directly influenced by parity and lactation will have to be improved by the combined effect of supplementary feeding plus the effect of parity and stage of lactation. Tsabong raw camel milk, at the time of the study, was of good keeping quality. The low FFA content of the milk is an indicator that there was minimal milk straining, bacterial contamination and that the milk confers to good storage quality.