The effects of energy intake during pregnancy in doe rabbits on pup birth weight, milk output and maternal body composition change in the ensuing lactation

Abstract

A study was made in rabbits on the effects of energy intake during pregnanoy on pup birth weight and survival, and on doe body composition and milk output in the ensuing lactation. In addition the experiment examined the effects of varying crudeprotein intakes during lactation on the rate of fat loss of does and the resultant energetic efficiency of milk production.Forty-seven multiparous cross-bred does were used. They were offered one of two diets in pregnancy, either diet HE (14-8 MJ digestible energy (DE)/kg D.M.) to appetite or diet LE (12-9 MJ DE/kg D.M.) at maintenance levels. After parturition seven does on each treatment were slaughtered and their body composition analysed (control groups). In lactation the remaining does were evenly allocated to receive either diet LE (195 g crude protein (CP)/kg D.M.) or diet HP (240 g CP/kg D.M.) to appetite. Litter sizes were standardized to six pups and litter growth rates were used as an indirect estimate of milk production. Does were then killed, at random, on day 9 or day 18 of lactation to give an estimate of changes in body composition as lactation progressed.Does offered diet HE during pregnancy had higher carcass fat levels at parturition than their counterparts offered diet LE (496 cf. 370 g/kg carcass D.M. respectively). Litter size was unaffected by dietary treatment during pregnancy but litter weights at birth were significantly greater in HE does (442 cf. 398 g respectively). Pup mortality at birth, however, was also much higher in these animals (28 cf. 9% respectively). Voluntary food intake in early lactation (day 1-9) was depressed by feeding diet HE during pregnanoy. Milk composition was affected by pregnancy diet, with does offered diet HE producing milk containing significantly higher fat levels (HE 123 g fat/kg milk cf. LE 105 g fat/kg milk).Doe carcass composition changes revealed that fat was usually mobilized in early lactation and gained as lactation progressed independent of dietary treatment. The protein content of the fat-free dry matter appeared to be relatively unaffected by the dietary treatments imposed. The data were used to derive an estimate of the partial efficiency of dietary energy utilization (fc) for milk output and maternal tissue gain. The line of best fit was described by the equation ER = 0-65 (±0-17) MEI-1-25, where ER = milk energy output + carcass energy change and MEI = metabolizable energy intake in MJ. INTRODUCTIONan< * m 8 O m e c a s e s even more, during the subsequent lactation (see recent review by Robinson, 1986). The reproductive cycle in mammals is character-Usually, therefore, the aim in meeting nutrient ized by temporal changes in tissue anabolism and needs for reproduction is to devise a nutritional catabolism to satisfy various productive processes regime which will produce a balance in the comand an understanding of the timing and causes of position of the body over the breeding cycle as a these fluctuations in body composition is funda-whole, rather than attempting to maintain its mental to practical anim...

Study of the energy and protein balance of pregnant rabbit does using two comparative methods

“…Taking the total body energy content of pregnant does as 100%, with the advancement of pregnancy both the total energy content of uterus and fetuses (1.75, 2.70, and 4.71%, respectively), and the energy content of fetuses alone (0.04, 0.58, and 2.34% respectively) represented an increasing proportion of the total energy content of the does' body. These data confirm the results according to which the energy amount of fetuses Acta Veterinaria Hungarica 53, 2005 and uteri is less than 5% of the total body energy on day 28 of pregnancy (Kamphues, 1985;Partridge et al, 1986). Figure 2 and Table 2 show the weight and chemical composition of uterus and fetuses.…”

Rabbit milk: A review of quantity, quality and non-dietary affecting factors

“…However, some days later the composition returns to levels approaching the original values. Christ et al (1996), Cole et al (1983), El-Sayiad et al (1994), Fraga et al (1989), Kowalska and Bielanski (2004), Kustos et al (1999), , Lebas et al (1996), Maertens et al (1994Maertens et al ( , 2005Maertens et al ( and 2006, Partridge and Allan (1982), Partridge et al (1983Partridge et al ( , 1986aPartridge et al ( and 1986b, Pascual et al (1996Pascual et al ( , 1999aPascual et al ( and 2000a and Xiccato et al (1999) Figure 5. Milk composition changes during the lactation period (literature compilation, see Table 3).…”

Long-term effect of selection for litter size and feeding programme on the performance of reproductive rabbit does 1. Pregnancy of multiparous does

“…On the other hand, some works have observed a reduction litter size at birth using high energy diets, related to an increase of the individual size of pups and/or an excessive fatness of does, which could impede foetal movement along the birth canal and so increase the probability of stillbirths (Partridge et al, 1986). This fact could partly explain the lower prolificacy of H1ME does.…”

“…Most of the trials did not show any significant effect of increasing dietary energy on litter size at birth . However, three long-term works have observed a decrease of the litter size at birth for does given high energy diets as consequence of the increase in pup mortality (Partridge et al, 1986;Parigi-Bini et al, 1996;Pascual et al, 1999), suggesting that high energy diets must be used carefully out of lactation in the long-term (see Figure 4).…”