Effects of Fat Supplementation and Immature Alfalfa to Concentrate Ratio on Lactation Performance of Dairy Cattle

Abstract

Forty-six multiparous Holstein cows were assigned 5 d postpartum to a completely randomized design employing a 2 x 3 factorial treatment arrangement. Factors were 0 or 5% added prilled fat (DM basis) substituted for shelled corn and alfalfa silage fed in forage-to-concentrate ratios of 45:55, 64:36, and 84:16 (DM basis). Interactions between fat and forage level were not observed for any of the parameters measured. Energy density, calculated using data from a digestibility trial, was similar between 45:55 and 64:36 diets (1.66 Mcal NE1/kg) and was lower with 84:16 diets (1.48 Mcal NE1/kg) for the 100 d trial. Fat supplementation increased energy density of the diets (1.67 vs. 1.53 Mcal NE1/kg). Dry matter digestibility, energy intake, and 4% FCM yields were similar for cows fed 45:55 and 64:36 diets and lower for those fed the 84:16 diets. Fat supplementation did not affect DM digestibility. Dry matter intake declined with increasing forage level and fat supplementation. Milk yield decreased as forage level increased. Fat supplementation did not affect yield of milk or FCM. Milk fat percentage was lower for cows fed 45:55 than 64:36 or 84:16 diets. Fat supplementation increased milk fat percentage. Milk protein yield decreased as forage level increased but was unaffected by fat supplementation. Results suggest higher levels of concentrate support higher milk yields, and prilled fat supplementation improves fat test when fed with immature forages. Prilled fat supplementation did not enhance lactation performance because of depressed DM intake in early lactation.

Effect of dietary energy source on energy balance, production, metabolic disorders and reproduction in lactating dairy cattle

“…In contrast to studies where extra glycogenic nutrients were fed, 13 [60,61,66,[68][69][70][71][72][73] out of 14 reported studies found a decrease in plasma NEFA levels. Plasma BHBA levels increased after feeding extra lipogenic nutrients in five out of eight studies [68,69,74,75]. Extra glycogenic nutrients were related to a decrease in plasma BHBA levels in eight out of nine reported studies [61,69,70,72,74,76].…”

“…Apart from an increase due to higher dietary fat content [69,74,75], plasma BHBA were also elevated with increasing dietary forage level [75]. Ruppert et al [68] found no increase in BHBA, as an indicator of NEB, when fat was added to a corn silage diet, in contrast to an alfalfa silage diet.…”

“…In general, the negative effect of extra lipogenic sources on dry matter intake is higher when the degree of saturation of fatty acids is lower, probably because of the more pronounced negative effects of unsaturated fatty acids on rumen carbohydrate fermentation. As a result, 73% of the studies on feeding extra lipogenic nutrients [15,61,63,65,75,100,101,104,106] and also 73% of the studies on increasing dietary glycogenic nutrients [61,[69][70][71][72]117] obtained a higher net energy (NE) intake in the treatment group compared to the control group, illustrated by Figure 4 shows an overview of studies that reported milk yield and composition after feeding either more glycogenic nutrients or lipogenic nutrients. Both feeding extra lipogenic nutrients or glycogenic nutrients had similar effects on kg of milk produced per day [8, 15, 60-72, 75, 77, 78, 82, 99-104, 106, 107, 110, 111, 115-122] …”

Suplementação de lipídeos de diferentes fontes em dietas para vacas Jersey na fase inicial de lactação

“…Aumentar a densidade de energia das dietas pode auxiliar na redução do balanço energético negativo, pois as dietas passam a atender à demanda de energia para produção de leite (Jerred et al, 1990). Palmquist (1988) observou que, em dietas com 8% de EE na MS, parte da EM (15 a 20%) foi oriunda de ácidos graxos de cadeia longa (AGCL).…”

Valor do farelo de arroz integral como fonte de gordura na dieta de vacas Jersey na fase inicial de lactação: digestibilidade aparente de nutrientes

“…Como exemplo, pode-se citar o estudo de Wu et al (1993) utilizando gordura protegida (sais cálcicos de óleo de palma), sebo ou ácidos graxos cristalizados (prilled fat) em nível de 2,5% sobre uma dieta com 3,7% de ácidos graxos, contendo 7,2% de Tabela 4 -Composição em ácidos graxos (g/100 g de gordura) das fontes de gordura Wu et al (1993), Grummer (1988), Shauff & Clark (1989), Jerred et al (1990) e Palmquist (1991 não encontraram efeito da suplementação na digestibilidade da fibra. Também não verificaram alterações na fermentação ruminal e na digestibilidade dos nutrientes com a adição de 2,2% de sebo em dietas contendo 10% de grãos de soja.…”