Differential effects of maternal undernutrition between days 1 and 90 of pregnancy on ewe and lamb performance and lamb parasitism in hill or lowland breeds1

Abstract

This study examined the hypothesis that responses of Scottish Blackface (BF, a hill breed) and Suffolk (SUF, a lowland breed) ewes to undernutrition between d 1 and 90 of pregnancy would differ. Over 2 consecutive breeding seasons, ewes (4 pens/treatment; 15 to 20 ewes/pen) were artificially inseminated and from d 1 to 90 after AI allocated to 0.75 (restricted; RES) or 1.0 (control; CON) energy requirements for ewe maintenance and fetal growth. From d 90 to term, all ewes were allocated feed to meet requirements for stage of pregnancy and expected litter size. On d 90, RES ewes had lighter BW (P = 0.001) and smaller BCS (P = 0.019) than CON ewes. Plasma NEFA concentrations were greater in RES than CON ewes (P = 0.048) at d 60 of pregnancy. Pregnancy length was longer for RES than CON ewes (P = 0.003). Lambs from SUF-RES ewes had lighter birth weights than SUF-CON lambs, but BF-RES lamb birth weights were not different from BF-CON lambs (interaction, P = 0.066). However, maternal undernutrition did not affect BW at weaning (P > 0.45). Between birth and 3 d of age, BF lambs maintained greater body temperatures (P < 0.001) and plasma concentrations of triiodothyronine (T3, P < 0.001) and thyroxine (P < 0.001) than SUF lambs. Lambs from RES ewes had greater concentrations of T3 (P = 0.026) than CON lambs, whereas these differences were greater between BF-RES and BF-CON lambs than between SUF-RES and SUF-CON lambs (interaction, P = 0.028). Maternal undernutrition did not affect lamb rectal temperature (P > 0.27). In yr 1 only, fewer lambs (P = 0.022) were reared to weaning by RES than CON ewes. Similarly, in yr 1 only, other strongyle fecal egg counts at weaning were greater in SUF-RES lambs than SUF-CON, BF-CON, or BF-RES lambs (interaction, P = 0.099). This experiment showed that lambs of a breed selected for lean tissue growth and normally maintained in a lowland environment were more affected by maternal undernutrition between d 1 and 90 of pregnancy than lambs of a hill breed managed in a more adverse environment.

Maternal behaviour and lamb survival: from neuroendocrinology to practical application

“…Ewes undernourished in pregnancy have reduced udder weight and mammary development (Mellor and Murray, 1985;Mellor et al, 1987), delayed onset of lactation (Mellor et al, 1987), reduced colostrum yield and milk production (Mellor and Murray, 1985;Hall et al, 1992;O'Doherty and Crosby, 1996) and increased lamb mortality (Kleeman et al, 1993;Hinch et al, 1996;Rooke et al, 2010). These ewes also display behavioral impairments, taking longer to interact with their lambs (Thomson and Thomson, 1949), displaying more aggression to the lamb, spending less time grooming and more time eating after birth (Dwyer et al, 2003), and are more likely to desert their lambs (Putu et al, 1988;Lindsay et al, 1990), than well-fed ewes.…”

Epigenetics and developmental programming of welfare and production traits in farm animals

“…Numerous studies consistently show that maternal undernutrition of the ewe in late pregnancy (after Day 100) reduces lamb birthweight (for a review, see Rooke et al 2015). Undernutrition before Day 100 has variable effects across different studies: severe early undernutrition has a marked effect on birthweight and mortality (Vincent et al 1985); and moderate undernutrition in early to mid-gestation generally does not affect birthweight, except in young and growing females (Munoz et al 2009) or ewes selected or adapted for a well-fed environment (Burt et al 2007;Rooke et al 2010). In these studies mortality was generally not affected if birthweight was not affected, although the study of Rooke et al (2010) reports increased lamb mortality with early undernutrition (to Day 90 of gestation), even in the absence of an effect on birthweight.…”

“…Undernutrition before Day 100 has variable effects across different studies: severe early undernutrition has a marked effect on birthweight and mortality (Vincent et al 1985); and moderate undernutrition in early to mid-gestation generally does not affect birthweight, except in young and growing females (Munoz et al 2009) or ewes selected or adapted for a well-fed environment (Burt et al 2007;Rooke et al 2010). In these studies mortality was generally not affected if birthweight was not affected, although the study of Rooke et al (2010) reports increased lamb mortality with early undernutrition (to Day 90 of gestation), even in the absence of an effect on birthweight. Conversely maternal overnutrition of ewe lambs results in a severe reduction in lamb weight, as the mother partitions nutrients towards the growth of her own tissues at the expense of the placenta and fetus .…”

“…For example, in one year of a study conducted over two consecutive years in which Scottish blackface and Suffolk ewes received either maintenance or 75% maintenance rations during Days 1-90 of pregnancy, the offspring of underfed Suffolk, but not underfed Scottish blackface, ewes had higher strongyle faecal egg counts at weaning age (Rooke et al 2010). The differences between breeding seasons could be attributed to a range of factors, including differences in lamb postnatal growth and grazing behaviour.…”

Effects of breed, parity and post-mating nutrition on reproductive wastage and pregnancy outcomes of Egyptian sheep

“…Ewe-lambs body weight did not differ at 50 or 90 days of pregnancy in the moderately-fed sheep, but it increased at Day 130, while body weight increased gradually in the high-fed group through pregnancy (Caton et al, 2009). On Day 90 of pregnancy, Rooke et al (2010) found that the low-fed group (75% of maintenance requirements) had lighter body weight and smaller body condition score, while maternal body weight did not differ at weaning.…”