Effects of a starch binding agent on in vitro rumen degradability of maize and sorghum starch

The objective of the study was to quantify the potential of a starch binding agent (BioProtectTM) to reduce in vitro rumen starch degradation of maize and sorghum particles that varied in size. Maize and sorghum grain samples were ground through 2-mm sieves with a Wiley mill and subsequently sieved to obtain these sizes: less than 250, 250 - 500, 500 - 1180, and 1180 - 2000 μm (i.e., very fine to coarse). All fractions were analysed separately for starch content. Samples were treated 24 hours before fermentation by spraying BioProtect onto the substrate. Both treated and untreated samples were fermented in vitro for 0, 6, 12 and 24 hours to quantify starch degradability. Rates of degradability (kd) were calculated with a first-order decay model. BioProtect was effective in decreasing starch degradability and rates of degradability for both grains (P <0.0001). The product was more effective with smaller particle size, by reducing starch degradability 17% for the smallest particles as opposed to 7% for the largest particles. A time interaction was observed (P <0.0001), which showed that the highest impact of BioProtect occurred after 12 hours of fermentation for both grains. The starch binding agent resulted in an effective decrease of in vitro starch degradation, but results were affected by particle size and fermentation time. Starch digestion could possibly be shifted to the small intestine with BioProtect

Veal calf performance in response to concentrate diets of different rumen degradable protein content

(South African J of Animal Science, 2000, 30, Supplement 1: 58-59

A comparison of the yield, nutritional value and predicted production potential of different maize hybrids for silage production

The yield, nutritional value and production potential of silage made from twenty one maize hybrids was compared. The digestibility of organic matter and predicted intake, mean retention time and milk production potential were found to differ between hybrids (p < 0.05). Acid detergent fibre content could not be used to accurately predict the metabolizable energy content of silage. (South African Journal of Animal Science, 2000, 30(1): 18-21

The production performance of lactating Jersey cows receiving varying levels of lucerne hay and oat silage as roughage sources

(South African J of Animal Science: 2000, 30, Supplement 1: 6-7

The effect of adding a lactic acid bacterial inoculant to maize at ensiling on milk production and milk composition of Jersey cows

(South African J of Animal Science, 2000, 30, Supplement 1: 78-79

The effect of adding a lactic acid bacterial inoculant to big round-bale oat silage on intake, milk production and milk composition of Jersey cows

(South African J of Animal Science, 2000, 30, Supplement 1: 80-81

Effect of late prepartum fibre-based diets on the live weight changes and reproduction of Holstein cows in the subsequent lactation period

The objective of this study was to evaluate two late prepartum fibre-based diets that differed in non-structural carbohydrate (NFC) and protein levels on live weight (LW) changes and fertility traits of Holstein cows until 120 days postpartum. At 30 days before calving, 120 pregnant Holsteins (heifers, n = 54 and dry cows, n = 66) from the Elsenburg herd were assigned to two nutritional treatments according to parity, expected calving date, LW, and milk production during the previous lactation. Prepartum heifers and cows were fed independently a similar type and level of a prepartum concentrate, associated with an ad libitum intake of either unchopped oat hay for the control group or a partial total mixed ration (pTMR: oat hay (48%), lucerne hay (43%) and soybean oil cake meal (9%)) for the treatment group. After parturition, cows in both the control and treatment groups were maintained on ad libitum cultivated irrigated kikuyu-ryegrass pastures, supplemented each with a post-partum concentrate of 7 kg/day from calving until 120 days in milk (DIM). As expected, young and still growing primiparous cows were significantly lighter in pre- and post-partum LW traits compared with mature multiparous cows (parity &gt; 3). Prepartum LW of cows was similar between the control and the treatment in both parity groups. Post-partum LW of the primiparous cows differed significantly between the control and the treatment, which were 488 ± 9 and 507 ± 13 kg, respectively. However, no difference was observed in terms of post-partum LW of multiparous cows of the control and the treatment groups, which were 579 ± 10 and 579 ± 8 kg, respectively. Primiparous cows that received the prepartum oat hay-based diet showed significant decrease in post-partum LW loss changes, LWnadir, LW loss at nadir and rate of LW loss from calving to LWnadir in comparison with their counterparts on the prepartum pTMR-based diet, but these LW traits were similar in multiparous cows. Prepartum diets did not have an effect on post-partum fertility parameters of the multiparous cows, whereas primiparous cows that received the control diet recorded a significantly longer interval from calving to first service (CFS) in the subsequent lactation in comparison with their counterparts fed the treatment diet i.e. 117 ± 9 and 86 ± 8 days, respectively. Proportions of cows that were pregnant at 120 DIM were similar in the subsequent lactation between groups that received the prepartum oat hay- and pTMR-based diets in both parity groups. Further research is required to investigate different prepartum feeding periods and nutritional approaches involving various levels and sources of energy and protein nutrients to encourage post-partum metabolic and hormonal responses that benefit the fertility of dairy cows in the subsequent lactation.Keywords: Dairy, dry period, non-structural carbohydrate, protein, postpartum, pregnanc

The effect of dietary rumen degradable protein content on veal calf performance

The objective of this study was to determine the undegradable dietary protein requirements of veal calves. Two experiments were carried out with Holstein bull calves from 3-10 days of age until slaughter at 20 weeks of age. Both experiments were divided into starter and finishing periods. Calves were offered starter pellets on an ad lib. basis from seven days of age. Diets were formulated to be iso-nitrogenous and iso-caloric, and differed in undegradable dietary protein content. In Experiment 1 calves were randomly assigned to one of three dietary treatments containing low (LD), medium (MD) or high (HD) levels of rumen degradable protein. In Experiment 2 calves received a starter diet containing either a high or a low level of rumen degradable protein. At the end of the starter period animals from both treatment groups were re-assigned at random to finisher diets containing either low or high rumen degradable protein levels, resulting in four treatment combinations, viz. LL, LH, HL and HH. There were no treatment differences for feed intake, body weight gain or feed efficiency during the starter period of either experiment. During the finishing period (weeks 12-20) of Experiment 1, calves receiving the LD diet had higher average daily gains than calves receiving the HD treatment. Feed conversion ratio for the LD treatment was also better than for the other two treatments. During the finishing period (weeks 11-20) of Experiment 2 the feed conversion ratio tended (P < 0.10) to differ between treatments: feed conversion ratio for the LL and HL treatments was more favourable than that for the LH treatment. Feed conversion ratio for the HH treatment was intermediate, and did not differ from that of the LL, HL or LH treatments. The level of crude protein degradability appears to have no effect on calf performance during the starter period, but it may, however, be beneficial to feed finisher diets with a lower crude protein degradability during the finisher period.Articl

Melamine in the feed and food chain

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