Replacing maize grain with dried citrus pulp in a concentrate feed for Jersey cows grazing ryegrass pasture

Abstract

Dried citrus pulp (DCP) is a high-fibre by-product of the citrus industry. In total mixed ration (TMR) systems it has been shown to maintain a more stable ruminal environment, improving overall production compared with maize. The aim of the study was to determine the effects of stepwise replacement of maize with DCP in a concentrate supplement on milk yield, milk composition and rumen health of Jersey cows grazing ryegrass pasture. Sixty-eight lactating Jersey cows (μ ± SD; 84.5 ± 43.8 days in milk, 20.4 ± 3.09 kg/day) were used in the trial. Cows were allocated to one of four treatments, with 17 cows per treatment, namely no DCP (NDCP): 0% replacement; low DCP (LDCP): 33% replacement; medium DCP (MDCP): 66% replacement; and high DCP (HDCP): 100% replacement. An additional six ruminally cannulated Jersey cows were randomly allocated to the NDCP and HDCP treatments in a two-period cross-over design. Milk yield decreased between 2.1 and 3.2 kg/day when maize was replaced with DCP. Milk fat content did not differ between treatments. However, treatment had a quadratic effect on milk protein and lactose content, with the LDCP and MDCP treatments having the highest values. No change in the diurnal ruminal pH curve and no differences in the rate and extent of pasture dry matter and neutral detergent fibre degradability between treatments were observed. In conclusion, replacing maize grain with DCP in a conventional concentrate diet led to a decrease in milk yield, while rumen health was maintained. ______________________________________________________________________________________

Effects of Replacing Extruded Maize by Dried Citrus Pulp in a Mixed Diet on Ruminal Fermentation, Methane Production, and Microbial Populations in Rusitec Fermenters

“…Thus, Zhao et al [49] reported no differences in rumen pH of Rusitec fermenters fed 50:50 forage:concentrate diets containing either 15% of pure citrus pectin or 15% of pure maize starch. Similarly, no differences in pH were reported when steers fed a tropical grass based diet were supplemented daily with 0, 1.5, or 2.5 kg of pelleted DCP [50], when DCP replaced maize in the concentrate fed to grazing cows [51], or when barley grains were totally replaced by DCP in a 50:50 forage:concentrate diet for dairy sheep [20]. Altogether, these results might indicate that the influence of DCP on rumen pH is more pronounced for high-concentrate than for medium-and high-forage diets.…”

A comparative analysis of the proximate and mineral composition of whole Citrus limon and Citrus clementina as a prospective alternative feed resource for livestock farming in South Africa

“…In the present study, the differences in the crude fiber were observed between the whole C. limon and C. clementina fruits may largely be due to the difference in the citrus species (Audu et al, 2018). Dried whole citrus fruit is a rich source of fiber and when used as livestock feed in a total mixed ration (TMR) feeding scheme since it supplies a stable ruminal environment in ruminants, thereby improving animal productivity (Steyn et al, 2017).…”

“…Citrus fruits as a by-product can be gathered in large quantities and processed as a prospective periodic livestock feed source to improve animal production (Steyn et al, 2017). Conversely, there is merit in evaluating the utilization of whole citrus fruit as an alternative livestock feed resource in South Africa as it could proffer an alternative or complementary/supplementary feed ingredient for livestock farmers.…”

“…This may largely be because of the continuous increase in the price of grains which is a major livestock feed for animals among other reasons (e.g., drought and low financial resources by local farmers). Processed citrus fruits as by-products could be fed to livestock as stand-alone feed, but they can be preserved for a longer period when dried and kept in a cool environment, thus forming a significant part of the annual feeding plan for animal farming (Steyn et al, 2017).…”

Pre- and postpartum effects of starch and fat in dairy cows: A review

“…Glucogenic-based ingredients consist of cereal grains and their milling by-products, molasses, beet and citrus pulps, roots and tubers such as cassava and potatoes and their by-products, and dried reclaimed bakery products (McDonald et al, 2002;Mosavi et al, 2012;Steyn et al, 2017). Fat increases the energy density of the diet (Schroeder et al, 2004), and in particular enhances plasma cholesterol, the major precursor for steroidogenesis, including luteal P 4 synthesis in postpartum cows .…”