Fat supplementation in animal production—ruminants

Abstract

In 198 I, 204 ooo tonnes of fat were used by the UK Compound Food Industry in the production of foods for farm animals (Ministry of Agriculture, Fisheries and Food, 1982). Of this, it has been estimated that 65000 tonnes (Meggison, 1982) were used in the production of ruminant rations (mainly for the dairy cow), the remainder being used for pigs and poultry. Since approximately 5 million tonnes of food were produced for ruminants, this is an average rate of addition of 13 g/kg diet, although, of course, this average conceals very wide variations. Is a further increase in the use of fat desirable?There are basically two reasons for the addition of fat to the diet of the ruminant animal, first, to act as an energy source and, second, to influence the composition of the final animal product in a particular desired direction.With the assistance of the microbes in the rumen, the ruminant is able to digest forage materials with a high cellulose content. Many of these materials are of relatively low digestibility and, as a result, the food intake of the animal is often limited by the bulk of the food rather than by its energy content, as is the case in simple-stomached animals (Baile, 1979). Therefore, there may be cases in which it is desirable to increase the mean concentration of metabolizable energy (ME) in the food and the easiest way to do this is to add fat to the diet. For example, a 600 kg dairy cow eating 9 kg/d of silage dry matter (ME content 1 1 MJ/kg) and 9 kg/d of concentrates (ME content 13 MJ/d) should give a milk yield of 28.3 l/d with a fat content of 4% and a solids-not-fat content of 8.5%. If 0.5 kg of fat is substituted for 0.5 kg concentrates, the yield of the same milk should increase to 31.0 l/d; i.e. by approximately 9%.This calculation is based on assumptions that the addition of fat does not affect the total food intake or the digestibility or metabolizability of the basal diet and that the ME content of the fat is 34 MJ/kg. It is proposed to discuss each of these assumptions in turn. Food intakeJohnson & McClure (1973) investigated the effect of adding either animal fat (HEF) or maize oil directly to grass at the time of ensilage: in some silages, 10 g ground limestone/kg were also added. Without limestone, the addition of up to 120 g HEF/kg reduced the voluntary intake by up to 27% in sheep and up to 5570 in steers. When limestone was added, the reduction in intake was less at the lower levels of addition of HEF but the same at the higher levels and, overall, the addition of limestone did not affect the food intake. When maize oil was added available at https://www.cambridge.org/core/terms. https://doi

The effect of rolled rape seeds on milk composition and lactational responses

“…Steele (1985) suggested that oil and fats exert an influence on DM consumption by physically preventing ruminal micro-organisms from gaining access to other dietary constituents or alternatively, free fatty acids released by hydrolysis may have toxic effects on some microbes, leading to altered populations within the rumen. The administration of 1.4 kg rolled rape seeds (HR) ( Table 2) per cow nonsignificantly increased the yield of milk, milk fat content (PO.05) and significantly increased daily fat production by 89 g per day similarly to the results obtained by Clapperton and Steele (1983). Strzetelski et al (1992) found a higher FCM yield among cows fed control diets without rape seeds and formaldehyde-or heat-treated rape seeds.…”

“…The negative effect of fat on dry matter intake tends to increase as fat saturation decreases and as the amount of fat supplementation increases (Pantoja et al, 1996). The effect of added fat on voluntary feed intake seems to depend on the type of fat used, the way in which it is added, and the amount used (Clapperton and Steele, 1983). Steele (1985) suggested that oil and fats exert an influence on DM consumption by physically preventing ruminal micro-organisms from gaining access to other dietary constituents or alternatively, free fatty acids released by hydrolysis may have toxic effects on some microbes, leading to altered populations within the rumen.…”

Effect of dietary canola on fatty acid composition of bovine adipose tissue, muscle, kidney, and liver1

“…High-fat diets can decrease feed intake in cattle (Clapperton and Steele, 1983). Steers, but not bulls, fed EC and GC had slightly reduced feed intakes.…”

Effect of inclusion of different forms of dietary fatty acid on the yield and composition of cow's milk

“…It is widely recognized that the high energy density of fats offers advantages when formulating rations for dairy cows, but in practice the average amount of fat added to dairy cake is very small -only ~ 13 g/kg in the UK (Clapperton & Steele, 1983). To some extent this reluctance to use fats is due to mechanical difficulties in cubing, but there are more fundamental objections to their inclusion.…”