Figueiredo F O M, Leite R F, St-Pierre N R, Resende K T, Almeida A K, Souza A P, Teixeira I A M A
UNESP - Universidade Estadual Paulista, Jaboticabal, São Paulo, Brazil.
The Ohio State University, Columbus, OH, USA.
J Anim Physiol Anim Nutr (Berl). 2017 Oct;101(5):1014-1025. doi: 10.1111/jpn.12539. Epub 2016 Jul 20.
The objective of this research was to estimate the energy and protein requirements for maintenance and growth in male (castrated and intact) and female Saanen goat kids between 15 and 30 kg BW. To determine the net energy requirements for maintenance (NE ) and the net protein requirements for maintenance (NP ), 75 goats (25 castrated and 26 intact males and 24 females) were used. Twenty-one goats (seven castrated and eight intact males and six females) were randomly assigned for slaughter to estimate the initial empty body composition. The 54 remaining animals (18 castrated and 18 intact males and 18 females) were randomly assigned in a split-plot design using a 3 × 3 factorial arrangement with three sexes and three levels of intake (ad libitum and restricted feed to 75% or 50% of the ad libitum intake). Within each sex, six blocks (three goats per block) were formed and one goat was randomly assigned to each level of intake. The 75% and the 50% of ad libitum rationing were determined daily, based on the DMI of the animal fed ad libitum on the previous day. All animals within block were slaughtered when the animal fed ad libitum reached 30 kg BW. The net energy requirements for gain (NE ) and the net protein requirements for gain (NP ) were obtained using 58 animals (20 castrated and 20 intact males and 18 females). The animals were fed ad libitum and slaughtered at targeted BW (15, 23 or 30 kg). Sex did not affect NE and NP (277.8 kJ/kg BW day and 2.98 g CP/kg BW day respectively), as well as NP (180.9 ± 6.48 g/kg EBW gain) in Saanen goat kids. However, castrated males and females had similar NE (varied from 12.6 ± 0.424 to 17.9 ± 1.38 MJ/kg EBW gain), greater than intact males (varied from 9.74 ± 0.420 to 10.7 ± 0.984 MJ/kg EBW gain), as the BW increased from 15 to 30 kg.
本研究的目的是估计体重在15至30千克的雄性（去势和未去势）和雌性萨能山羊羔维持和生长所需的能量和蛋白质。为了确定维持净能量需求（NE）和维持净蛋白质需求（NP），使用了75只山羊（25只去势雄性、26只未去势雄性和24只雌性）。随机挑选21只山羊（7只去势雄性、8只未去势雄性和6只雌性）进行屠宰，以估计初始空腹体成分。其余54只动物（18只去势雄性、18只未去势雄性和18只雌性）采用3×3析因设计的裂区设计随机分配，该设计包含三个性别和三个采食水平（自由采食以及将饲料限制为自由采食量的75%或50%）。在每个性别中，形成6个区组（每个区组3只山羊），并将1只山羊随机分配到每个采食水平。自由采食量的75%和50%根据前一天自由采食动物的干物质采食量（DMI）每日确定。当自由采食的动物达到30千克体重时，屠宰区组内的所有动物。使用58只动物（20只去势雄性、20只未去势雄性和18只雌性）获得增重净能量需求（NE）和增重净蛋白质需求（NP）。这些动物自由采食，并在目标体重（15、23或30千克）时屠宰。性别对萨能山羊羔的NE和NP（分别为277.8千焦/千克体重·天和2.98克粗蛋白/千克体重·天）以及NP（180.9±6.48克/千克空腹体重增重）没有影响。然而，随着体重从15千克增加到30千克，去势雄性和雌性的NE相似（从12.6±0.424到17.9±1.38兆焦/千克空腹体重增重），大于未去势雄性（从9.74±0.420到10.7±0.984兆焦/千克空腹体重增重）。
