Nutritional status of adult ewes during early and mid-pregnancy. 2. Effects of supplementation with selenised yeast on ewe reproduction and offspring performance to weaning

Effect of selenium and vitamin E supplementation on the metabolic status of dairy goats and respective goat kids in the peripartum period

This study aimed to examine the effects of selenium (Se) and vitamin E (vitE) supplementation on blood cell counts and blood metabolite concentrations in goats and their kids. Fifteen Saanen goats (average age 6 years of age; average initial body weight of 70 ± 10 kg) and 21 ½ Saanen × ½ Pardo Alpine crossbred goat kids (average body weight of 3.70 ± 0.64 kg) were used. Animals were distributed in a completely randomized design with five replicates per diet for mother goats and seven for goat kids and randomly assigned into three groups in the following diets: CON, control basal diet; Se, inclusion of 3.2 mg of Se/kg DM; SevitE, inclusion of 3.2 mg Se/kg DM and 1145 IU/day vitE/kg DM. Effects of time were observed on red blood cells, hemoglobin, hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin in goats and goat kids. Effects of time were observed on differential counts of leucocytes, lymphocytes, and monocytes in goat kids. Interaction was observed for high-density lipoprotein and total protein in goats and for triglycerides, beta-hydroxybutyrate (BHBA), and gamma-glutamyltransferase (GGT) in goat kids. Effects of time were observed on low-density lipoprotein, triglycerides, glucose, lactate, BHBA, non-esterified fatty acids (NEFA), creatinine, aspartate-aminotransferase, and GGT in goats and all blood metabolites in goat kids. Selenium, vitE, or association in the evaluated levels are not sufficient to change blood cell counts when supplied in diets for goats or goat kids. However, the effect of time or interaction between time and diets change the blood metabolite concentrations in the animals.

Multiple injections of vitamin E and selenium improved the reproductive performance of estrus-synchronized Awassi ewes

The aim of the current study was to investigate the effects of injecting estrus-synchronized ewes with vitamin E and selenium (Se) on their reproductive performance. Awassi ewes (n = 74) were randomly assigned into one of two groups. Group one (control, n = 36) did not receive vitamin E/Se injections, and group two (vitamin E/Se, n = 38) received 13.6-mg/kg BW of vitamin E plus 0.045-mg/kg BW of Se. Concurrent with estrus-synchronization program, vitamin E/Se injections were given at the time of insertion, withdrawal, and 19 days after withdrawal of intravaginal sponges. At all injection times, serum samples were collected (20 ewes per group) to measure Se contents. Pregnancy rates were evaluated by progesterone assay and by ultrasonography, respectively, at days 19 and 40 after sponge removal. Lambing rate, singles and twins%, sex ratio (M:F), and birth weight were recorded at lambing. Vitamin E/Se injections did not affect (P > 0.25) BW at lambing or BW change of ewes from breeding to lambing. Vitamin E/Se injections tended (P = 0.08) to decrease total pregnancy losses from 44.8 to 24.3%, subsequently, injections positively improved (P < 0.05) pregnancy rates determined by progesterone assay (from 80.6 to 97.4%) and ultrasonography (from 63.9 to 86.8%). Although overall fertility was not affected, vitamin E/Se injections markedly increased the percentage of ewes that lambed after only one service from 64.0 to 93.3%. Singles and twins%, lamb sex ratio, and birth weight of lambs were not affected (P > 0.20) by vitamin E/Se injections. Under conditions of our study, multiple injections of vitamin E/Se improved the reproductive performance of estrus-synchronized ewes.

The case for pre-parturient selenium and iodine supplementation of ewes for improving lamb survival

Lamb survival is an issue of high relevance to the Australian sheep industry, as lamb-survival rates have direct bearing on overall reproductive performance of the sheep, and also constitute a main concern from an animal welfare perspective (Mellor and Stafford 2004). Both genetic and management factors play an important role in this complex issue (Hinch and Brien 2014). Ewe nutrition is of particular relevance as the intrauterine growth conditions prepare the lamb for the crucial transition to life outside the uterus. Effects of body condition of the ewe during various stages of the pregnancy have been investigated in detail, yet much less is known about the critical role of micronutrient provision to the ewe. Although several risk factors for selenium (Se) and iodine (I) subclinical deficiencies exist for sheep on pasture in Australia, determining micronutrient status in sheep or pasture is not straightforward. Several studies have separately found effects of Se and I supplementation on lamb survival. Studies investigating the interaction of Se and I supplementation have been few but results have demonstrated an interaction between Se and I. With increased twinning rates as a result of increased selection of numbers of lambs weaned, nutritional demands during pregnancy across flocks are increasing, and effects of micronutrients on lamb health and survival have greater impact. New opportunities in nutritional research are encouraging new studies into the effects of Se and I supplementation on lamb survival.

The effect of late pregnancy supplementation of ewes with vitamin E on lamb vigour

The experiment measured lamb responses to supplementation of the pregnant ewe diet with vitamin E above requirement. Crossbred ewes were mated with either Suffolk or Texel rams. Twin-bearing ewes were randomly allocated (approximately 21 months of age at allocation) to one of four treatment groups (20 ewes per group, 10 mated with Suffolk and 10 with Texel rams). Treatments imposed were 50, 100, 150 or 250 IU supplementary vitamin E per ewe per day to give a four treatment by two sire-type factorial experimental design. Ewes were fed concentrates to meet energy requirements for stage of pregnancy and hay ad libitum. Diets were introduced approximately 6 weeks before lambing. Blood samples were obtained prior to introduction of diets, 17 days after introduction of diets and within 24 h of lambing from a subset of eight ewes per treatment (32 total). Colostrum samples were obtained from 10 ewes per treatment, 12 h after birth of the first lamb. All births were observed and a lamb vigour score was assigned to each lamb 5 min after birth. At 1 and 12 h after birth, rectal temperature, and at 12 h after birth, sex, crown-rump length and BW of each lamb were recorded. Mean ewe plasma α-tocopherol concentration prior to introduction of the diets was 1.5 μg/ml (s.e.m. 0.09) and did not differ between groups. There were positive linear (P < 0.001) effects of dietary vitamin E on plasma (17 days after introduction of diets) and colostrum (12 h after birth) α-tocopherol concentrations. Lamb vigour scores were superior (P < 0.001) for lambs sired by Texel rather than Suffolk rams but there were no differences as a result of vitamin E supplementation. Lamb mortality was low and unrelated to either sire or supplementary vitamin E. Lamb birth and weaning weights were also unaffected by vitamin E supplementation. Supplementing the ewe with vitamin E therefore had no effect on any lamb measurements.

Organic and inorganic selenium: III. Ewe and progeny performance

Selenium is an essential micronutrient in sheep, and deficiency can limit lamb growth and survival. To evaluate how different chemical forms of Se administered to mature ewes at comparative dosages affect ewe and progeny performance, 240 ewes were divided into 8 treatment groups (n = 30 each) and drenched weekly with no Se; at the maximum FDA-allowed concentration with inorganic Na-selenite or organic Se-yeast (4.9 mg Se/wk); with inorganic Na-selenate (8.95 mg Se/wk); or with inorganic Na-selenite and organic Se-yeast at supranutritional concentrations (14.7 and 24.5 mg Se/wk, respectively). The treatment period started approximately 2 wk before breeding and lasted for 62.5 wk. Ewes of the no-Se and Se-yeast groups continued treatments for another 21 to 24 wk through a second lambing season. Chemical form or dosage of Se did not affect ewe reproductive performance based on proportion of ewes lambing in each treatment group, or number of lambs born, nursed, or weaned per ewe (all P > 0.10). Ewes receiving the highest supplementation rate of Se-yeast at 24.5 mg Se/wk had higher BCS (scale 1 to 5) at the end of yr 1 (2.95 vs. 2.66; P = 0.05) than ewes receiving Se-yeast at 4.9 mg Se/wk. Performance was better in lambs from ewes receiving Se-yeast at 24.5 mg Se/wk than in lambs from ewes receiving Se-yeast at 4.9 mg Se/wk or no Se. In yr 1, lambs from ewes receiving Se-yeast at 24.5 vs. 4.9 mg Se/wk were heavier at 120 d of age (37.0 vs. 34.2 kg; P = 0.05). In yr 2, lambs from ewes receiving Se-yeast at 24.5 mg Se/wk were or tended to be heavier at 60 d of age than lambs from ewes receiving no Se (21.2 vs. 19.0 kg; P = 0.04) or lambs from ewes receiving Se-yeast at 4.9 mg Se/wk (19.2 kg; P = 0.09). This effect was more pronounced in ewes raising multiple lambs. We conclude that supranutritional supplementation of ewes with Se-yeast at 24.5 mg Se/wk improves lamb growth and ewe health without negatively affecting reproductive performance.

Effects of supplementation with fish oil and barium selenate on performance, carcass characteristics and muscle fatty acid composition of late season lamb finished on grass-based or concentrate-based diets

The objectives of this study were to investigate the effects of fish oil supplementation on performance and muscle fatty acid composition of hill lambs finished on grass-based or concentrate-based diets, and to examine the interaction with selenium (Se) status. In September 2006, 180 entire male lambs of mixed breeds were sourced from six hill farms after weaning and finished on five dietary treatments: grazed grass (GG), grass +0.4 kg/day cereal-based concentrate (GC), grass +0.4 kg/day cereal-based concentrate enriched with fish oil (GF), ad libitum cereal-based concentrate (HC) and ad libitum fish oil-enriched concentrate (HF). Within each treatment, half of the lambs were also supplemented with barium selenate by subcutaneous injection. At the start of the trial, the proportion of lambs with a marginal (<0.76 μmol/l) or deficient (<0.38 μmol/l) plasma Se status was 0.84 and 0.39, respectively. Compared with control lambs, GG lambs treated with Se had higher (P < 0.01) plasma Se levels, whereas erythrocyte glutathione peroxidase activity was higher (P < 0.01) for Se-supplemented lambs fed diets GG and GF. However, Se supplementation had no effects on any aspect of animal performance. Fish oil increased (P < 0.05) levels of 22:5n-3 and 22:6n-3 in the Longissimus dorsi of HF lambs but otherwise had no effect on the health attributes of lamb meat. There were no significant effects of fish oil on dry matter intake, animal performance or lamb carcass characteristics. Daily carcass weight gain (CWG; P < 0.001), carcass weight (P < 0.01) and conformation score (P < 0.01) increased with increasing concentrate inputs. Lambs fed concentrate-based diets achieved a higher mean CWG (P < 0.001), dressing proportion (P < 0.001) and carcass weight (P < 0.011), and were slaughtered up to 8.3 days earlier (P < 0.05) and at 1.2 kg lower (P < 0.05) live weight than pasture-fed lambs. However, carcasses from grass-fed lambs contained lower levels of perinephric and retroperitoneal fat (P < 0.05), and had less fat over the Iliocostalis thoracis (P < 0.001) and Obliquus internus abdominis (P < 0.05). Meat from grass-fed lambs also had lower levels of 18:2n-6 and total n-6 fatty acids compared with those finished indoors. The results of this study demonstrate that fish oil supplementation has some benefits for the health attributes of meat from lambs fed concentrate-based diets but not grass-based diets. Supplementing Se-deficient lambs with barium selenate will improve Se status of lambs fed zero-concentrate diets, but has no additional benefit when lambs are already consuming their daily Se requirement from concentrates or when fish oil-enriched diets are fed.

Effects of plane of nutrition of ewes in early and mid-pregnancy on performance of the offspring: female reproduction and male carcass characteristics

This study investigated the effects of different planes of nutrition in early pregnancy (EP) and mid-pregnancy (MP) of crossbred ewes on carcass characteristics of male offspring and reproductive performance of female offspring. During EP (d 1 to 39 after synchronized mating) ewes were allocated 60% (low, L-EP), 100% (medium, M-EP), or 200% (high, H-EP) of their energy requirements for maintenance. Between d 40 and 90 (MP), ewes were then allocated 80% (M-MP) or 140% (H-MP) of their maintenance energy requirement. After d 90, all ewes were fed to fully meet energy requirements for late pregnancy. Male offspring (n = 83) were reared on a grass-based system and slaughtered at 42, 46, or 50 kg of BW. Female offspring (n = 60) were reared on a grass-based system, mated at 8 mo, and performance recorded until weaning of their first lamb crop. Concentrations of leptin, an adiposity indicator, in female offspring varied with the plane of maternal nutrition in early pregnancy. The L-EP offspring had greater leptin concentrations than H-EP offspring (P = 0.04), with M-EP offspring showing intermediate concentrations. Reproductive performance of female offspring was not affected by maternal plane of nutrition (P > or = 0.16). Female H-EP offspring gave birth to heavier lambs (generation 2 offspring) than M-EP (P = 0.006) with L-EP offspring intermediate. Male offspring of L-EP dams showed a trend toward poorer carcass conformation (P = 0.06) and increased fat classification (P = 0.07), consistent with increased fat depths over the loin (P = 0.02). There was a significant interaction between plane of nutrition in early pregnancy and mid-pregnancy for female offspring BW at 2 mo postmating and 16 wk postlambing (P < or = 0.04), and for male offspring perinephric and retroperitoneal fat and tissue depth (P < or = 0.02). For dams offered diet L-EP during early pregnancy, diet H-MP gave heavier offspring with more perinephric and retroperitoneal fat. In contrast, for dams offered diet H-EP during EP, diet M-MP gave offspring that were heavier or fatter or both. Maintenance level of nutrition in EP followed by M-MP or H-MP treatments resulted in offspring intermediate in fatness and BW. The data indicate that adaptations in EP and MP to compensate for nutritional deprivation or nutritional excess can alter the BW, adiposity, conformation, and leptin concentrations of offspring. Such changes have potential to alter health and lifetime productive performance.

Effect of supplementation with barium selenate on the fertility, prolificacy and lambing performance of hill sheep

Six weeks before mating, the ewes on six hill farms were randomly assigned to receive either a subcutaneous injection of a long-acting supplement containing 50 mg/ml selenium as barium selenate, or no injected selenium. Before the treatment, the mean activity of glutathione peroxidase (GSHPx) in the ewes on the six farms ranged from 166 to 592 U/g haemoglobin (Hb) and their plasma selenium concentrations ranged from 0.60 to 1.61 micromol/l. Treated ewes had higher plasma selenium concentrations and higher GSHPx activities than control ewes during the study. Conception rates were higher in the treated ewes than in the control ewes. At six weeks, the lambs born to the treated ewes had higher plasma selenium and GSHPx levels than the controls. The treated ewes reared 9 per cent more lambs than the control ewes. The treated ewes had lower abortion rates, and higher liveweights and body condition scores than the controls. There were weak but positive associations between the plasma selenium and GSHPx levels of the ewes and their reproductive performance.