Efeitos de níveis de energia na dieta utilizando sais de cálcio de ácidos graxos sobre o valor nutritivo das dietas e qualidade do leite em cabras leiteiras no periparto ABSTRACTPeripartum is a critical period for dairy goats, as dry matter intake (DMI) is not enough to supply the energy requirement for foetal growth and subsequent lactation. The objective of this study was to evaluate the use of calcium salts of fatty acids (CSFA) to increase dietary energy level of peripartum dairy goats and its effects on nutritive value of diets and milk quality. Twenty multiparous Saanen goats (body weight 63.5±10.3 kg) were distributed in a completely randomised design in four treatments at the following dietary energy levels: 2.6 Mcal of metabolisable energy per kg of dry matter (Mcal ME/kg DM) -control diet; and 2.7, 2.8, and 2.9 Mcal/kg DM -with added CSFA. Goats were housed in individual stalls and evaluated in the peripartum period, by measuring body weight (BW), DMI, dry matter and nutrient digestibility of diets, blood composition, and milk quality and yield. Increasing dietary energy level to 2.9 Mcal ME/kg DM had no effect on BW and did not limit DMI. CSFA supplementation increased intake of total digestible nutrients and did not affect fibre digestion. Blood triglycerides and cholesterol concentration increased with CSFA addition. The treatments had no effect on milk yield and composition; however, CSFA supplementation changed the fatty acid concentration of milk fat, increasing levels of polyunsaturated and essential fatty acids. In conclusion, peripartum dairy goats supplemented with CSFA to increase dietary energy level up to 2.9 Mcal ME/kg DM had a greater supply of total digestible nutrients and showed altered fatty acid concentration of milk fat.Index terms: Digestibility, calcium soap, fatty acid, Lactoplus ® , protected fat. RESUMOO periparto é um período crítico para cabras leiteiras, onde a ingestão de matéria seca (IMS) não é suficiente para suprir os requerimentos energéticos para o crescimento fetal e lactação subsequente. Neste estudo, objetivou-se avaliar o uso de sais de cálcio de ácidos graxos (SCAG), para aumentar o nível de energia na dieta de cabras leiteiras no periparto e seus efeitos sobre o valor nutritivo das dietas e qualidade do leite. Vinte cabras multíparas (63,5±10,3 kg) foram distribuídas em delineamento inteiramente casualizado, em quatro tratamentos com os seguintes níveis de energia na dieta: 2,6 Mcal de energia metabolizável por kg de matéria seca (EM/kg de MS) -dieta controle; 2,7; 2,8; e 2,9 Mcal de EM/kg de MS -com adição de gordura protegida. As cabras foram confinadas em baias individuais e avaliadas durante o período do periparto, acompanhando o peso corporal (PC), IMS, digestibilidade da matéria seca e dos nutrientes da dieta, concentração bioquímica sanguínea, produção e qualidade do leite. O aumento no nível de energia da dieta até 2,9 Mcal de EM/kg de MS não teve efeito sobre PC e não limitou a IMS. A suplementação com SCAG aumentou a ingestão de nutrientes digestíveis...

-The objective of this study was to evaluate the use of calcium salts of fatty acids (CSFA) to increase the dietary energy levels for Saanen goats and their effects on the lactation curve, dry matter intake, body weight, and economic results of the goats. Twenty multiparous goats, weighing an average of 63.5±10.3 kg, were randomly assigned to one of four treatment groups, each receiving one of the following dietary energy levels: a control diet consisting of 2.6 Mcal of metabolizable energy per kg of dry matter (Mcal ME/kg DM) or a test diet supplemented with CSFA (Lactoplus ® ) to obtain 2.7, 2.8, or 2.9 Mcal ME/kg DM. Goats were housed in individual stalls and were fed and milked twice daily. The animals were evaluated until 180 days in milk by measuring dry matter intake and milk yield. These measurements were used to calculate feed efficiencies and the cost-benefit ratio of diet and lactation curves using Wood's nonlinear model. Increasing dietary energy levels showed no effect on body weight. Supplementation with CSFA did not limit dry matter intake; however, it changed the shape of the lactation curve by promoting a late peak lactation with a longer duration. Milk yields at 180 days in milk had a quadratic increase with a maximum energy level at 2.85 Mcal ME/kg DM. Increasing the dietary energy level for Saanen goats using CSFA changes their lactation curves, with the best milk production achieved with a 2.85 Mcal ME/kg DM diet; however, the greatest economic results were obtained with a 2.7 Mcal ME/kg DM diet.

According on the fat source included in the diets for goats, the milk production can be increased and milk fatty acid composition can be improved. This study was conducted to evaluate the inclusion of protected fat (CSFA - calcium salts of fatty acids) in the diets of lactating Saanen goats on milk production and composition. Five Saanen goats (63.23 ± 9.08 kg body weight and 105 ± 3 days of lactation) were distributed in a Latin square design (5 × 5) with five diets: control (without the addition of CSFA) and the other diets with: 6.25, 12.50, 18.75 and 25.0 g CSFA per kg dry matter (g/kg DM), respectively. Dry matter intake (DMI) and milk production (MP) were evaluated. Milk samples were collected to determine milk composition and fatty acid profile. Feed efficiency (FE) was estimated. The supplementation of CSFA up to 25 g/kg DM did not influence the DMI, MP and FE. Milk components production (g/d) was not influenced by the inclusion CSFA in the diet; however, there was a linear reduction of 0.87 g protein per kg of milk for each 1% CSFA included in the diet. The concentration of linolenic acid (18:3n-3) in milk was improved with a maximum point of 24 g of CSFA per kg DM. CSFA can be included in the diets of lactating Saanen goats up to 25 g/kg DM with no interference on DMI and MP.

Feeding goats with calcium salts of fatty acids (CSFA) can supply ruminants with lipids, with minimal effects on ruminal fermentation and fiber digestibility. However, there is a shortage of information on the effect of CSFA on characteristics of rumen fermentation in grassland goats. Thus, the present study aimed to assess the addition of CSFA to concentrate on the parameters of rumen fermentation of grazing goats. Five rumen cannulated goats were distributed in a Latin square 5x5 design (treatments: 0%, 1.5%, 3.0%, 4.5% and 6.0% CSFA. The pH, ammonia N and volatile fatty acids (VFA) content were analyzed in the ruminal fluid at 0, 2, 4, 6 and 8 hours after concentrate supplementation. The pH and ammonia N concentration showed a linear effect with the addition of CSFA. There was no effect observed for the VFA molar concentration after grazing goats were fed with the experimental diet. In conclusion, further research is needed to investigate the addition of CSFA to goat diets because there is evidence that CSFA increases ruminal pH and decreases excess ruminal ammonia without changing the VFA concentration in the rumen fluid.

No abstract