Effects of stage of lactation and dietary forage level on body composition of Alpine dairy goats

Abstract

Multiparous Alpine does (42) were used to determine how stage of lactation and dietary forage level affect body composition. The feeding and body composition portion of the study had a 2 x 3 factorial arrangement of treatments. Eighteen does were fed a 40% forage diet (40F) and 18 received a diet with 60% forage (60F) for approximately 2, 4, or 6 mo of lactation (59 +/- 1.3, 116 +/- 1.0, and 184 +/- 1.4 d, respectively), followed by determination of body composition (6 does per diet at each time of slaughter). Does were assigned sequentially to treatments as kidding occurred. The 60F diet had 20% more dehydrated alfalfa pellets than the 40F diet, with higher levels of corn and soybean meal and inclusion of supplemental fat in the 40F diet. Initial body composition measures were made with 6 other does a few days after kidding (0 mo; 4 +/- 0.6 d). Before parturition, does were fed a 50% concentrate diet free choice. Intake of dry matter was greater for 60F than for 40F, average daily gain tended to be affected by an interaction between diet and month (0, 24, 121, -61, 46, and 73 g), and 4% fat-corrected milk was less in mo 5 to 6 than earlier. Internal fat mass was greatest among times at 6 mo and greater for 40F than for 60F. Mass of the gastrointestinal tract was less for 40F than for 60F and decreased with increasing time in lactation. Concentrations of fat in the carcass (13.8, 13.1, 16.5, 11.2, 11.5, and 14.4%), noncarcass tissues (18.6, 24.2, 33.3, 14.3, 16.5, and 24.5%), and empty body (16.5, 18.7, 25.2, 12.9, 14.1, and 19.5% for 40F at 2 mo, 40F at 4 mo, 40F at 6 mo, 60F at 2 mo, 60F at 4 mo, and 60F at 6 mo, respectively) were affected by stage of lactation and diet. Based on daily change in tissue mass and energy, energy concentration in tissue mobilized or accreted was 16, 20, and 32 MJ/kg in 1 to 2, 3 to 4, and 5 to 6 mo of lactation, respectively. In conclusion, based on tissue mass, more energy was expended by the gastrointestinal tract with 60F than with 40F. Considerable internal fat appeared to be mobilized in early lactation, particularly with the diet moderate to high in forage, with more rapid and a greater magnitude of repletion by does consuming the diet lower in forage. The concentration of energy in tissue mobilized or accreted varied with stage of lactation, being considerably greater at 5 to 6 mo of lactation than earlier.

Effects of level of feeding on energy utilization by Angora goats1

“…Ngwa et al (2009a) determined that an average energy concentration in tissue accreted by growing meat goats (3/4 Boer × 1/4 Spanish and Spanish) is 17.3 MJ/kg, unless there has been a prolonged limited nutritional plane (e.g., 28 wk, average of 47 g of ADG). Ngwa et al (2009b) measured body composition of lactating Alpine dairy goats in early, mid-, and late lactation while consuming 40 or 60% forage diets. Based on empty BW gain of 56 g/d, the mid-lactation energy concentration in tissue accreted of 20 MJ/kg is most relevant to the present experiment.…”

Effect of maternal yeast feeding on dam performance and serum health biomarkers of Beetal goat kids

“…Although milk lactose synthesis depends primarily on serum glucose of the dam, the mammary gland has the ability to synthesize normal lactose, even in a hypoglycemic dam (Kaneko et al, 2008), which indicates that dams might not be benefitting from extraneous sources of glucose precursors for increased milk lactose content. Stage of lactation, composition of diet, fodder concentrate ratio and breed of the animal are among the factors that can affect the response of animals to yeast supplementation (Ngwa et al, 2009).…”

Multinutritional blocks as a food strategy to optimize the use of concentrate for lactating goats

“…As acetic acid is one of the main precursors of the milk fat, its reduction is directly related to the decreasing of the milk fat (Silva & Antunes, 2018). Ngwa et al (2009) evaluated two levels of concentrated in diets of Alpine goats, 40 or 60%, and they did not verify differences in the production of milk and fat level.…”