Abstract

Several studies have recently investigated the birth weight of puppies from different pure-bred dogs. In general, birth weight decreased with litter size but there has been limited investigation into factors influencing growth during early development. The first month of life includes three stages of puppy development: neonatal (0–13 days), transitional (14–20 days), and first week of socialisation period (21–28 days). The aim of this study was to evaluate bodyweight and growth rate of 120 Labrador Retriever (LR) puppies during early development. Puppies from 19 show-line bitches under standardised composition of diet during pregnancy and lactation were involved in this study. Puppies were weighed weekly from birth to 28 days using an electronic digital balance. Relative weight gain (ΔW) was calculated for the neonatal period [ΔW₁ = (W_day14-W_day0)/W_day0], transition period [ΔW₂ = (W_day21-W_day14)/W_day14] and first week of socialisation period [ΔW₂ = (W_day28-W_day21)/W_day21]. The effects of covariates on ΔW were assessed using generalised linear mixed models. Sex and photoperiod had no impact on relative weight gain, whereas litter size had a significant effect at ΔW₁ (p < .01) but not at ΔW₂ and at ΔW₃. Relative weight gain was slightly lower in puppies from larger litter born during short photoperiod on ΔW1. A deeper knowledge of the factors that significantly influence weight gain during the first four weeks of life could be useful for physiological and behavioural science as well as for canine breeding management.

• Highlights

• 120 Labrador Retriever puppies were weighed weekly from birth to 28 days using an electronic digital balance.

• Relative weight gain (ΔW) was calculated for the neonatal period (ΔW₁), transition period (ΔW₂) and first week of socialisation period (ΔW₃).

• Litter size had a significant effect on relative weight gain at ΔW₁ but not at ΔW₂ and ΔW₃.

• Relative weight gain was slightly lower in puppies from larger litter born during short photoperiod on ΔW_1.

摘要

最近有几项研究调查了来自不同纯种狗的幼犬的出生体重。一般而言，出生体重随着产仔数的增加而降低，但对影响早期发育过程中生长的因素的研究很少。生命的第一个月包括幼犬发育的三个阶段：新生儿（0-13天），过渡期（14-20天）和社交期的第一周（21-28天）。这项研究的目的是评估120只拉布拉多（LR）幼犬在早期发育过程中的体重和生长速率。在妊娠和哺乳期间，在标准化饮食结构下，来自19个母系母犬的幼犬参与了这项研究。从出生到28天，每周都要使用电子数字天平称重幼犬。相对增重（ΔW）计算为新生儿期[ΔW ₁  =（W _day14 -W _day0）/ W _day0 ]，过渡期[ΔW ₂  =（W _day21 -W _day14）/ W _day14 ]和第一周社会化周期[ΔW ₂  =（W _day28 -W _day21）/ W _day21 ]。使用广义线性混合模型评估协变量对ΔW的影响。性和光周期对相对增重没有影响，而同窝仔规模有在ΔW一个显著效果₁（p  <0.01），但不是在ΔW ₂和ΔW ₃。在ΔW1短暂的光周期内出生的较大窝仔的幼犬相对体重增加稍低。对生命的最初四周内会显着影响体重增加的因素有更深入的了解，可能对生理和行为科学以及犬种管理非常有用。

• 强调

• 使用电子数字天平从出生至28天每周称重120只拉布拉多幼犬。

• 相对增重（ΔW）计算为新生儿期（ΔW ₁），过渡期（ΔW ₂）和第一周社会化期间（ΔW的₃）。

• 产仔曾在ΔW对相对增重一个显著效果₁但不是在ΔW ₂和ΔW ₃。

• 在ΔW1的短光周期内出生的较大窝仔幼犬的相对体重增加略低_。