The objective of this study was to evaluate the performance of F1 (Holstein × Zebu) cows in lactation according to different levels of substitution of soybean meal for a protein equivalent non-protein nitrogen originated from slow-release urea (SRU). Eight F1 (Holstein × Zebu) cows in the first third of lactation, with an average milk yield of 12.7 kg (±3.1 kg)/day and a live weight of 552 kg (±30 kg), were used. The experimental design was composed of two simultaneous 4 × 4 Latin squares, with the following treatments: 100% soybean meal and 0% SRU; 66% soybean meal and 34% SRU; 34% soybean meal and 66% SRU; and 0% soybean meal and 100% SRU. Sorghum silage, used as roughage, was supplied together with the concentrate. Feed intake and digestibility as well as milk yield and milk composition were measured. The obtained data were subjected to analysis of variance, adopting a 5% probability level. No intake variable showed significant differences among the treatments, and the mean values for the intakes of dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) were 18.35 2.62 and 5.85 kg/day, respectively. The results for apparent digestibility also did not show differences among treatments, with DM, CP and NDF averaging 58.16, 58.64 and 36.21%, respectively. Milk yield and composition were similar among the treatments. The average 4%-fat-corrected milk yield was 13.39 kg/animal day. Intake, digestibility and milk yield and composition variables are not changed according to the substitution of the soy protein for slow-release urea. Thus, for average-milk-yield crossbred.animals, this substitution depends on economic variables only.
The objective with the current study was to evaluate the effects of a commercial mixture of essential oils (capsaicin, eugenol, cinnamaldehyde, and carvacrol) microencapsulated with increasing inclusions (0, 1.5, 3.0 and 4.0g/day) on intake, digestibility, performance and milk composition of 20 primiparous Holstein cows confined in sand-bedded stalls. There was no interaction between treatment and observation periods, and the effect of treatments was not significant (P>0,05) for dry matter intake, expressed as % body weight (BW) and kg/day; crude protein (% BW); ether extract (% BW); neutral detergent fiber; acid detergent fiber (% BW); dry matter digestibility (%); crude protein (%); ether extract (%); neutral detergent fiber (%); milk production (kg); milk fat (%); milk protein (%); lactose (%); total solids (%); nonfat dry extract (%); somatic cell count (log); and urea nitrogen (mg/dL). However, evaluating each period, a significant decrease (P<0,05) on milk production, and an increase in total solids concentrations (%) were observed. There was no difference (P>0,05) for total solids levels (%) and somatic cell count (log). We concluded that the use of essential oils containing capsaicin, eugenol, cinnamaldehyde and carvacrol does not affect intake, digestibility, and milk production and composition of primiparous Holstein cows.
Objetivou-se com o presente trabalho avaliar os efeitos de uma mistura comercial de óleos essenciais (capsaicina, eugenol, cinamaldeído e carvacrol) microencapsulados com inclusões crescentes (0; 1,5; 3,0 e 4,0g/dia) sobre o consumo, digestibilidade, desempenho e a composição do leite de 20 vacas Holandesas primíparas confinadas em baias com cama de areia. Não houve interação entre os tratamentos e os períodos avaliados, e o efeito dos tratamentos não foi significativo (P>0,05) para as variáveis consumo de matéria seca, expresso em % PV e em kg/dia, proteína bruta (% PV), extrato etéreo (% PV), fibra em detergente neutro (% PV), fibra em detergente ácido (% PV); digestibilidade da matéria seca (%), proteína bruta (%), extrato etéreo (%), fibra em detergente neutro (%); produção de leite (kg) e seus componentes gordura (%), proteína (%), lactose (%), sólidos totais (%), extrato seco desengordurado (%), contagem de células somáticas (log) e nitrogênio ureico (mg/dL). No entanto, avaliando separadamente os períodos testados, encontrou-se diminuição significativa (P<0,05) na produção de leite e aumento nas concentrações de sólidos totais (%). Não houve diferença (P>0,05) para os teores de extrato seco desengordurado (%) e contagem de células somáticas (log). Pôde-se concluir que a utilização de óleos essenciais contendo capsaicina, eugenol, cinamaldeído e carvacrol não influencia o consumo, digestibilidade, produção e composição do leite de vacas Holandesas primíparas.