Gaughan J B, Cameron R D, Dryden G M, Young B A
Department of Animal Production, University of Queensland, Gatton, Australia.
J Anim Sci. 1997 Jul;75(7):1764-72. doi: 10.2527/1997.7571764x.
Fifty-four Large White gilts were used to determine the effect of body composition at selection (145 d of age) on the onset of puberty and subsequent reproductive development until 202 d of age. Gilts were assigned to one of three groups based on their backfat depth at selection: 10 to 12 mm (L), 13 to 15 mm (M), and 16 to 18 mm (F). All of the F gilts, 92% of the M gilts, and 67% of the L gilts reached puberty by slaughter at 202 d of age. Data from a subgroup (first 67% to reach puberty in each group; L = Lp, M = Mp, and F = Fp) was also used. The M (Mp) and F (Fp) gilts reached puberty at 172 d (166 d) and 170 d (166 d) of age, respectively, but the L (Lp) gilts at 184.5 d were 12 d (18 d) older than M (P < .05), Mp (P < .001), and F (P < .01), Fp (P < .001) gilts. The Lp (97.68 kg) and Mp (98.33 kg) gilts were lighter (P < .01) than Fp (108.72 kg) gilts at puberty. There were no differences (P < .05) among the L, M, and F gilts in terms of backfat depth or weight at puberty. The L (Lp) gilts had a mean of 1.16 (1.75) estrous cycles, which was lower (P < .01) than for M (Mp) and (P < .01) F (Fp) gilts, with 1.96 (2.29) and 2.25 (2.33) cycles, respectively. L (Lp) gilts had fewer (P < .05) follicles, 13.14 (12.63), than either M (Mp), 19.08 (18.71), or F (Fp), 18.25 (17.42) gilts. The number of corpora lutea was not influenced (P > .05) by grouping at selection, but Fp gilts had fewer (P < .05) corpora lutea than Mp or Fp gilts. Live weight at slaughter was not influenced (P > .10) by grouping at selection or subgrouping at puberty. The L gilts with a mean of 18.05 mm of backfat at slaughter were leaner (P < .05) than the F (21.66 mm) but not (P > .10) the M gilts (19.41 mm). Subgrouping had no effect. Fat deposition and protein deposition were higher (P < .05) in those animals that attained puberty. We conclude that the rate of fat and protein deposition seems to be one of the determinants of puberty attainment.
选用54头大白猪后备母猪，以确定选种时（145日龄）的体组成对初情期启动以及直至202日龄后续繁殖发育的影响。根据选种时的背膘厚度，将后备母猪分为三组：10至12毫米（L组）、13至15毫米（M组）和16至18毫米（F组）。所有F组后备母猪、92%的M组后备母猪以及67%的L组后备母猪在202日龄屠宰时已达初情期。还使用了一个亚组的数据（每组中最先达到初情期的67%；L = Lp组、M = Mp组、F = Fp组）。M（Mp）组和F（Fp）组后备母猪分别在172日龄（166日龄）和170日龄（166日龄）达到初情期，但L（Lp）组后备母猪在184.5日龄达到初情期，比M（P < 0.05）、Mp（P < 0.001）、F（P < 0.01）和Fp（P < 0.001）组后备母猪大12天（18天）。初情期时，Lp组（97.68千克）和Mp组（98.33千克）后备母猪比Fp组（108.72千克）后备母猪轻（P < 0.01）。L、M和F组后备母猪在初情期时的背膘厚度或体重方面无差异（P < 0.05）。L（Lp）组后备母猪平均有1.16（1.75）个发情周期，低于M（Mp）组（P < 0.01）和F（Fp）组（P < 0.01），M（Mp）组和F（Fp）组分别有1.96（2.29）个和2.25（2.33）个发情周期。L（Lp）组后备母猪的卵泡数量（13.14个，12.63个）比M（Mp）组（19.08个，18.71个）和F（Fp）组（18.25个，17.42个）少（P < 0.05）。选种分组对黄体数量无影响（P > 0.05），但Fp组后备母猪的黄体数量比Mp组或Fp组少（P < 0.05）。屠宰时的活重不受选种分组或初情期亚组划分的影响（P > 0.10）。屠宰时背膘平均厚度为18.05毫米的L组后备母猪比F组（21.66毫米）瘦（P < 0.05），但与M组（19.41毫米）相比无差异（P > 0.10）。亚组划分无影响。达到初情期的动物脂肪沉积和蛋白质沉积更高（P < 0.05）。我们得出结论，脂肪和蛋白质沉积速率似乎是达到初情期的决定因素之一。
