During the conduct of an experiment designed to examine the nutritional management of dairy cows in late pregnancy, four cows out of 72 suffered from acute haemoglobinuria two to four weeks after calving. Thirty-six thin and 36 fat cows were individually fed one of three diets based on a total mixed ration with different energy or protein concentrations during the last 3 to 4 weeks before expected calving date. After calving, cows grazed pasture and were offered 6 kg dry matter of pelleted concentrates daily. The P concentrations of the feeds offered suggested that the cows' diets were marginally deficient in P relative to requirements. Plasma P concentrations were significantly (P < 0.05) lower in fat cows than in thin cows during the first 6 weeks of lactation (0.87 versus 1.12 mmol/L), but precalving diet had no effect (P > 0.05). Concentrations of plasma inorganic P of the four fat cows that developed acute haemoglobinuria were less than 0.3 mmol/L. However, plasma P concentrations in another 12 cows, none of which displayed overt symptoms, declined to similar levels. It appeared that inadequate dietary P may have predisposed cows to acute haemoglobinuria, but the precipitating cause was not readily obvious.
A series of six experiments compared the production of lactating dairy cows eating either fresh herbage or the pressed herbage remaining after the partial extraction of juice. Irrigated perennial pasture and irrigated lucerne (Medicago sativa) were used in different experiments. With forage-harvested pasture, extraction removed an average of 42.1 g of protein per kg dry matter (DM) of pasture processed. An average of 85% of the DM of the original fresh pasture was left as pressed pasture. The process lowered the in vitro digestibility, total nitrogen, and cell contents of the herbage, and raised the cell wall constituents. It also reduced herbage phosphorus, potassium, magnesium and sodium, but increased herbage calcium slightly. The milk yield of cows fed an equivalent DM intake of pressed residue was, on average, 6% lower than the milk yield of cows fed fresh pasture. The responses shown by the milk constituents were inconsistent. With lucerne, extraction removed an average of 95.9 g of protein from each kg of fresh herbage and an average of 74% of the lucerne was left as pressed lucerne. This reduced the quality of the pressed residue as determined by in vitro digestibility (5%), Kjeldahl nitrogen (19%) and neutral detergent fibre (27%). However, there was no significant loss of production for cows on the pressed herbage, although there were small differences. It is concluded that lucerne would appear to have the greater potential for a leaf protein extraction industry in the irrigated areas of the Goulburn Valley of Victoria.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.