The effect of ewe size and nutritional regimen beginning in early pregnancy on ewe and lamb performance to weaning

Abstract

Ewe size, pregnancy nutrition and pregnancy rank are known to affect the productive performance of ewes and their offspring. The aim of the present study was to compare the effects of two nutritional regimens, from day 21 to day 140 of pregnancy, in singleton-and twin-bearing ewes of two different mean weights, taken from a single flock. The study included Large ewes offered Ad lib (Large-Ad lib, n= 151), Large ewes offered Maintenance (Large-Maintenance, n = 153), Small ewes offered Ad lib (Small-Ad lib, n = 155) and Small ewes offered Maintenance (Small-Maintenance, n = 153) that were either singleton-or twin-bearing. During the period day 21 to day 140 Maintenance and Ad lib feeding regimens included Large and Small ewes and singleton-and twin-bearing ewes. At days 1 and 140 of pregnancy Large ewes were heavier (P < 0.05) and of greater (P < 0.05) body condition than Small ewes. Similarly, at days 1 and 140 of pregnancy twin-bearing ewes were heavier (P < 0.05) than single-bearing ewes. At day 1 of pregnancy there was no difference in ewe liveweight and body condition scores between Maintenance and Ad lib-fed ewes, but by day 140 ewes in the Ad lib regimen were heavier (P < 0.05) and had greater (P < 0.05) body condition than Maintenance ewes. There was an interaction (P < 0.05) between ewe nutritional regimen and lamb birth rank for lamb birth weight such that twin lambs born to Maintenance regimen ewes were lighter (P < 0.05) than their counterparts born to Ad lib ewes (4.52 ± 0.06 versus 5.23 ± 0.06 kg respectively). This relationship was not observed in singletons. There was also an interaction (P < 0.05) between ewe size and nutritional regimen for lamb birthweight. Birth weights did not differ between lambs born to either Small or Large ewes on the Ad lib feeding regimen. However, lambs born to Small ewes on the Maintenance feeding regimen were lighter (P < 0.05) than their counterparts born to Large ewes (5.09 ± 0.07 versus 5.37 ± 0.07 kg respectively). At day 100 of lactation lambs born to Large ewes were heavier (P < 0.05) than those born to Small ewes (32.65 ± 0.37 versus 31.16 ± 0.35 kg respectively) and those born to Ad lib ewes were heavier (P < 0.05) than those born to Maintenance ewes (32.77 ± 0.37 versus 31.03 ± 0.36 kg respectively). This study shows that level of dam pregnancy nutrition has a greater effect on twin-born lambs than their singleton-born counterparts. Furthermore, the data suggests that the heavier liveweights at weaning of lambs born to Large ewes may not have compensated for their dams' greater nutritional requirements compared to their smaller counterparts.

Motivation to obtain a food reward of pregnant ewes in negative energy balance: Behavioural, metabolic and endocrine considerations

“…A study by Kenyon et al (2009) found that low body weight ewes had lighter lambs than high body weight ewes at 100 days of lactation. We did not find any differences in birth weight between lambs born to ewes of different BCS, although there is evidence that nutrition during pregnancy can affect birth weight of the lambs depending on the timing and duration of the under-or over-nutrition period (Kenyon et al, 2009;Redmer et al, 2004). Pregnancy lengths were shorter in HBC compared to LBC ewes, with MBC ewes having intermediate pregnancy lengths.…”

“…Therefore, metabolic and endocrine parameters that provide measures of energy balance may be associated with the level of hunger experienced by the animal, as estimated using motivational tests. In addition, nutrition during pregnancy may have implications for the offspring; undernutrition during pregnancy may lead to lower birth (Kenyon et al, 2009;Redmer et al, 2004) and weaning weights (Kenyon et al, 2009a). Ewe nutrition also has implications for wool parameters (Adams et al, 2002(Adams et al, , 2007.…”

Altering ewe nutrition in late gestation: II. The impact on fetal development and offspring performance1

“…Studies have outlined the influence of both maternal BCS and gestational nutrition on lamb birth weight (Gardener et al, 2005;Kenyon et al, 2009;Caton and Hess, 2010;Meyer et al, 2010), highlighting its importance in the detection of fetal growth restriction and/or adequate maternal nutrition. In the present study, despite the difference in ewe DMI and BCS (McGovern et al, 2015), there was a lack of difference observed in lamb birth weight.…”

“…Although previous studies have investigated the effects of gestational nutrition on fetal development (Kenyon et al, 2009(Kenyon et al, , 2011aBlair et al, 2011), this study focused on assessing offspring performance after individual ewe feeding, where daily feed intake of the ewe, as opposed to group feeding, was monitored, thus allowing for a more accurate individual energy intake calculation on a daily basis. Although there was a lack of difference observed in lamb birth weight, organ weight, and glucose concentration, significant effects from the nutritional imbalance were observed in lamb thoracic circumference, fore leg length, and lamb behavior, measured at birth.…”

“…Studies have reported that altering the level of maternal nutrition up to d 130 of gestation can affect fetal growth, influencing birth weight (Caton et al, 2009) and postnatal growth (Kenyon et al, 2009). Optimum ewe and lamb behavior at parturition is crucial to the well-being and survival of the neonate, with Dwyer et al (2003) reporting that maternal nutrient restriction impairs the duration of ewe grooming behavior expressed immediately after lambing, thus weakening the ewe-lamb bond.…”