Seasonal effects on birth weight of lambs born to prolific ewes maintained under intensive management

Seasonal effects on birth weight (BWT) of lambs were studied in a prolific Assaf flock maintained under intensive management conditions with birth records of 7775 lambs distributed across all months in a period of 11 years. The average BWT was 4.21 kg. Month of the year had a significant (P < 0.001) effect on BWT, with the highest average BWT in April (4.6 kg) and the lowest average BWT in September (3.8 kg). The seasonal effect was noted for single lambs and lambs born in litters of 2 to 4 lambs. Gestation length, day length, rate of change in day length and heat load had significant (P < 0.001) effects on BWT. Day length during the early stage of gestation was inversely related to BWT while rate of changes in day length during the latter stages of gestation were directly associated with BWT.     

Digestibility,ruminal fermentation,blood metabolites and antioxidant status in ewes supplemented with DL‐methionine or hydroxy‐4 (methylthio) butanoic acid isopropyl ester

The effects of supplementing ewe diets with either DL‐methionine (DL‐Met) or 2‐hydroxy‐4 (methylthio) butanoic acid isopropyl ester (HMBi) were investigated on ruminal in situ degradability of grain and forage diets, in vivo digestibility, rumen fermentation, blood metabolites and antioxidant status. Six ruminally cannulated ewes were used in a replicated 3 × 3 Latin square design with 28‐day periods. The dietary treatments were as follows: (i) no supplemental Met (control; CON), (ii) DL‐Met at 1.2 g/kg DM intake and (iii) HMBi at 1.8 g/kg dry matter (DM) intake. Corn grain, barley grain and alfalfa hay were evaluated for their ruminal degradability by both in situ incubation and effective degradability measurements of DM, neutral detergent fibre (NDF) and acid detergent fibre (ADF). Compared to other treatments, HMBi supplementation increased (p < 0.05) the digestibility of organic matter, crude protein and NDF and also tended (p = 0.08) to increase the digestibility of DM and ADF. Moreover, HMBi supplementation increased (p < 0.01) total VFA concentrations, the molar proportions of valerate and iso‐butyrate in the rumen. Compared to the CON treatment, DL‐Met and HMBi treatments tended (p = 0.08) to increase the molar proportion of acetate but decreased (p < 0.05) ruminal ammonia‐N concentration. Ewes supplemented with HMBi and DL‐Met recorded greater (p < 0.05) serum concentrations of glutathione peroxidase, total antioxidant capacity and superoxide dismutase than the CON treatment. Serum concentrations of glucose, total protein, albumin, high‐density lipoprotein and very low‐density lipoprotein were greater (p < 0.01) and serum urea nitrogen (p < 0.05), malonyl dialdehyde and triglyceride were lower (p < 0.02) in the HMBi and DL‐Met animals than in the CON ewes. The results concluded that HMBi is a very effective form of dietary Met supplementation for ewes with a positive effect on digestion, rumen fermentation and serum antioxidant function.     

内蒙古牧区察哈尔羔羊饲粮钙磷适宜水平研究

本试验采用4个不同钙磷水平的饲粮饲喂断奶后察哈尔羔羊,研究钙磷对断奶羔羊生长、钙磷营养消化代谢和排放量、骨骼的影响。选取70日龄健康、体重(16.27±3.33) kg断奶察哈尔羔羊120只(公母各半),随机分成4个组,每组30个重复,每个重复1只羊,分别饲喂4种饲粮,其钙磷含量分别为:Ⅰ组,0.49%、0.28%;Ⅱ组,0.55%、0.32%;Ⅲ组,0.64%、0.47%;Ⅳ组,0.87%、0.70%。饲养试验期65 d,其后,每组选6只羔羊(公母各半),全收粪法进行消化代谢试验。试验结果:1)饲粮钙磷水平对断奶羔羊平均日增重、体尺、干物质采食量和饲粮转化率影响皆不显著(P>0.05);2)血清钙含量Ⅳ组显著高于其他3组,血清碱性磷酸酶Ⅰ组显著高于其他3组(P<0.05);3)Ⅰ组钙表观消化率显著高于其他3组(P<0.05),随饲粮钙磷水平升高羔羊钙磷排放量增加(P<0.05);4)Ⅳ组胫骨灰分含量显著高于Ⅰ组(P<0.05),Ⅰ组跖骨灰分含量显著低于Ⅲ、Ⅳ组(P<0.05),胫骨磷含量Ⅳ组显著高于其他3组(P<0.05);5)冬春季节改变羔羊饲喂模式增加了内蒙古地区草原生态系统中钙磷的输入。综上所述,饲粮钙磷水平升高降低了断奶羔羊的钙表观消化率,显著增加了钙磷的排放量,提高了羔羊骨骼钙磷沉积。在本试验条件下,饲粮钙磷含量分别为0.49%、0.28%,内蒙古地区冬春季断奶羔羊即可获得较好的生长性能。     

Behavior of ewes and lambs subjected to restraint fostering

The objective of this study was to investigate the development of maternal-filial social attachments between ewes and alien lambs using the technique of "restraint fostering." Forty-eight to 72 h after parturition, 22 Targhee -type ewes were separated from their natural lambs, placed in restraining devices ( stanchions ) and each exposed to a single alien lamb. After a period of 1 or 4 d of restraint, the ewes were subjected to five 10-min lamb acceptance tests over a 48-h period. The observer recorded butts and butt attempts by the ewe and successful and unsuccessful suckle attempts by the lamb. The ewe-lamb pairs were then housed in pens with other groups of ewes and lambs and observed intermittently for acceptance behaviors. Six of the 14 ewes restrained for 4 d and none of the eight ewes restrained for 24 h met the criterion for successful adoption within 48 h. After being housed in group pens, adoptions were achieved by three ewes in the 1-d group and an additional four ewes in the group restrained for 4 d. Ewes restrained for 24 h were significantly more aggressive toward fostered young than ewes restrained for 4 d. In addition, the proportion of successful suckling attempts was significantly lower for lambs fostered on ewes in the 1-d group. Both groups showed a decline in butts and butt attempts over successive acceptance tests, but while the proportion of successful suckling attempts declined for lambs housed with 1-d ewes, they increased over time for lambs fostered on ewes restrained for 4 d.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relationships between plasma concentrations of placental lactogen, insulin-like growth factors, metabolites and lamb size in late gestation ewes subject to nutritional supplementation and in their lambs at birth

The relationships between placental lactogen (PL), insulin-like growth factor (IGF) -1 and -2, insulin, glucose and nonesterified fatty acids (NEFA) were studied in 10 triplet-bearing ewes in late gestation (120-129 days) which were on ad libitum feeding. To extend the range of plasma metabolite concentrations the ewes received a continuous abomasal infusion from 100 days of gestation until delivery. Three were infused with glucose (160 g/day), 2 received sodium caseinate and 3 were infused with control fluid alone. From 120 days the animals were fed 3 hourly intervals from a belt feeder to achieve steady state and at 125-130 days had intravenous plasma samples pooled for analysis. There was no effect of nutritional supplementation on birth weight. Casein supplementation was associated with reduced maternal PL concentrations but glucose supplementation had no effect on PL concentrations. Circulating PL concentrations showed a positive correlation to IGF-2 activity (r = 0.64, P less than 0.05) and a negative relation to IGF-1 concentrations (r = -0.73, P less than 0.05). IGF-1 levels were higher (P less than 0.05) and IGF-2 levels were lower (P less than 0.05) in nutritionally supplemented ewes. In the ewe, NEFA concentrations showed a negative relationship to IGF-1 (r = -0.75, P less than 0.05) and a positive relationship with IGF-2 (r = 0.87, P less than 0.1). Similar relationships were observed in the ewe at term. These observations suggest that nutritional factors and PL may be important determinants of IGF-2 secretion in the late-gestation ewe. They suggest the possibility that IGF-2 mediates the lipolytic effects of PL.(ABSTRACT TRUNCATED AT 250 WORDS)     

酵母硒和酵母铬对羔羊生长性能、胴体品质、血液激素及代谢产物的影响

文章旨在研究日粮添加酵母硒和酵母铬对羔羊生长性能、胴体品质、血液相关指标的影响。试验选择平均体重为(26±4.75)kg的呼伦贝尔羔羊60只,随机分为6组,每组10只,每只羊作为1个重复。日粮采用2×3多因子设计,其中2个酵母硒水平(0和0.3 mg/kg,以硒计)和3个酵母铬水平(0、0.2和0.3 mg/kg,以铬计),试验共进行12周。随着酵母铬添加水平的升高,羔羊采食量显著线性升高(P <0.05)。酵母硒组羔羊末重、总增重和日增重随酵母铬添加水平的升高显著线性升高(P <0.05)。无酵母硒组随酵母铬添加水平的升高,血浆葡萄糖水平显著线性升高(P <0.05)。血浆甘油三酯和胰岛素水平随酵母铬添加水平的升高表现为显著二次曲线效应(P <0.05)。酵母硒组血浆甘油三酯和胰岛素水平随酵母铬添加水平的升高显著线性升高(P <0.05),而血浆尿酸含量显著线性下降(P <0.05)。无酵母硒组随酵母铬添加水平的升高,眼肌面积和胴体蛋白沉积量显著线性升高(P <0.05)。酵母硒组添加酵母铬对羔羊胴体相关指标均具有显著影响(P <0.05),其中屠体重、热胴体和冷胴体重、眼肌面积和能量沉积量随酵母铬添加水平表现为显著二次曲线效应(P <0.05),而脂肪含量和脂肪沉积量显著线性降低(P <0.05)。综上所述,硒酵母与铬酵母联合使用可以提高羔羊生产性能和改善胴体组成,改善血液激素和代谢产物,从而提高羊肉品质。     

Responses of pregnant ewes and young lambs to cold exposure

The effects of cold stress were studied in pregnant ewes during the last three weeks of gestation and in their progeny during the first three days of life. In general, ewes were unaffected by treatment whereas changes were observed in the cold-stressed lambs. Cold-induced changes in lambs included physical weakness, depression, and poor nursing response. Serum concentrations of glucose and insulin were lowered whereas concentrations of blood urea nitrogen, alkaline phosphatase, aspartate aminotransferase, lactate dehydrogenase, triglycerides, and cortisol tended to be higher in cold exposed lambs. The mortality rate was higher (40%) in cold-stressed lambs than in lambs kept at warmer temperatures (10%). At necropsy, cold-exposed lambs had reduced amounts of adipose tissue in perirenal areas, and extensive subcutaneous hemorrhages and edema in the distal portions of the thoracic and pelvic limbs.     

Growth performance,carcass characteristics,fatty acid composition and CLA concentrations of lambs fed diets supplemented with different oil sources

Quality food for human consumption will always be the aim for animal producers. Quantity and composition of fat deposits (fatty acid profile) strongly influences meat quality in ruminants, especially via increasing conjugated linoleic acid (CLA) concentration, which is known to have beneficial anticarcinogenic, antiatherogenic, antidiabetic and cholesterol reduction properties for human health. Awassi lambs are one of the main and most consumed meat sources in the Middle East area; however, studies addressing the fat content of CLA and methods to enhance its concentrations in this breed are still rare. For this reason, the aim of this study was to evaluate the effect of adding two different oil sources (soybean oil (SBO) and sunflower oil (SFO) at two levels (1.8 and 3%)) on growth performance, carcass characteristics and fatty acid profile of fat in Awassi lambs. Oil supplementation had no effect on growth performance or carcass characteristics, while fatty acid composition changed according to the site of extraction. CLA concentrations were increased in the tail fat deposit, with 1.8% SBO and in intermuscular fat deposit with 3% SFO. Intermuscular fat is the one most naturally consumed by humans, serving to improve food quality.     

Effects of three anthelmintic regimes on milk yield of ewes and growth of lambs

Forty ewes were allocated into one of four groups (n = 10) and were treated with albendazole (ALB) (3.8 mg kg(-1)) before lambing (group A), with ALB before and after lambing (group B), with moxidectin (MXD) (0.2 mg kg(-1)) before lambing (group C) or were untreated controls (group D). Counts of nematode eggs in faeces and coprocultures were carried out during the study, as well as ewes' milk yield measurements and lamb weighings. Pre-treatment mean eggs per gram (epg) counts were 640, 715, 625 and 630 for groups A, B, C and D, respectively (P > 0.05); respective counts 21 days after treatment were 5, 0, 0 and 690 epg, whilst 70 days after treatment they were 380, 145, 40 and 1120 epg. Mean lactation milk yield was 3527.5, 3893.5, 3786.4 and 3285.9 ml for groups A, B, C and D, respectively; no significant difference was evident among the four groups in milk yield collected during the suckling period, although subsequently, group B or C ewes yielded significantly more milk than controls (P < 0.05). Mean birthweight of lambs were 3.56, 3.45, 3.59 and 3.26 kg for groups A, B, C and D, respectively (P = 0.045); subsequently, lambs from treated ewes were significantly heavier than lambs from control animals (P < 0.001). We conclude that anti-parasitic treatment during the last month of pregnancy contributed to an increased birthweight of lambs of treated ewes, whilst the cumulative effect of two doses of ALB or the long persistent efficacy of MXD provided a longer protection of animals against new parasitic infections and contributed to a lactation persistence.     

Effect of feed flushing during summer season on growth, reproductive performance and blood metabolites in Malpura ewes under semiarid tropical environment

Feed scarcity during hot summer months is one of the major predisposing factors for low reproductive efficiency of livestock reared in hot semiarid environment. A study was conducted to assess the effect of concentrate supplementation during summer months on growth, reproductive performance, and blood metabolites in Malpura ewes. Twenty adult Malpura ewes were used in the present study. The ewes were divided into two groups viz, group 1 (n?=?10; control) and group 2 (n?=?10; concentrate supplementation). The study was conducted for a period of 35 days covering two estrus cycles. In the first cycle, only PGF_2α was given to all ewes, while in second cycle, all ewes were synchronized for estrus using progesterone-impregnated intravaginal sponges and pregnant mare serum gonadotropin. The animals were allowed for grazing for 8–10 h per day. Apart from grazing, group 2 ewes were supplemented with concentrate mixture at 1.5 % of body weight. Concentrate supplementation had significant influence on body weight, ADG, estrus percentage, estrus duration, onset of estrus, ovulation response, plasma glucose, total protein, and urea. The present study reveals that ewes supplemented with concentrate mixture at 1.5 % of body weights during summer season significantly influenced the growth and reproductive performance of Malpura ewes. Further, the study signifies the importance of providing additional feed supplementation to ewes kept grazing under the conditions of a hot, semiarid environment to improve their reproductive efficiency.     

Effects of cinnamaldehyde, garlic and juniper berry essential oils on rumen fermentation, blood metabolites, growth performance, and carcass characteristics of growing lambs

The objective of this study was to examine the effects of cinnamaldehyde (CDH), garlic (GAR) and juniper berry (JUN) essential oils (200 mg/kg of DM) on performance and carcass characteristics of lambs fed a barley-based concentrate diet ad libitum. For this purpose, 40 ewes' lambs (23.5 ± 1.11 kg initial live weight, LW) were used in a random block design over a 13-week period. Feeding CDH, GAR or JUN did not affect dry matter intake (DMI) but the average daily gain (ADG) of lambs supplemented with CDH and JUN was higher (P = 0.002) as compared to lambs fed GAR or the control diet. Feed conversion (DMI/ADG) was numerically improved when lambs were fed CDH (4.8) and JUN (4.7) compared to those fed GAR (5.2) or the control diet (5.3). There were no effects of feed additives on ruminal pH and concentrations of ammonia and total VFA. Serum concentrations of glycerol and total glycerides were lower and higher (P ≤ 0.03) in lambs fed CDH or JUN respectively, as compared to lambs fed GAR or the control diet. Hot dressed carcass weight was similar among treatments (23.7 ± 0.75 kg; P = 0.18) whereas saleable meat tended (P = 0.13) to increase (+ 9%) in lambs fed CDH and JUN compared to those fed GAR or the control diet. Feeding CDH, GAR or JUN had little effect on the overall fatty acid composition of back fat and liver and only minor effects on meat flavour characteristics.     

The effect of the ratio of standardized ileal digestible lysine to metabolizable energy on growth performance, blood metabolites and hormones of lactating sows

A total of 335 lactating sows (Landrace × Large White) were used in two experiments to determine the optimum ratio of standardized ileal digestible lysine (SID-Lys) to metabolizable energy (ME) for mixed parity sows during lactation. In Exp. 1, 185 sows (weighing an average of 256.2 ± 6.5 kg and having an average parity of 3.4 ± 0.3) were allocated to one of six experimental diets in a completely randomized block design within parity groups (1, 2, and 3+). The experimental diets were formulated to contain 3.06, 3.16, 3.20, 3.25, 3.30 or 3.40 Mcal/kg of ME and each diet was fed to the sows throughout a 28 day lactation. All diets provided a similar SID-lysine level (0.86%). As a result, the diets provided a SID-Lys:ME ratio of 2.81, 2.72, 2.69, 2.65, 2.61 or 2.53 g/Mcal ME. Sow feed intake was significantly (P < 0.01) affected by the energy content of the diet as well as by sow parity. Using regression analysis, feed intake was shown to be maximized at 3.25, 3.21, 3.21 and 3.21 Mcal/kg of ME for parity 1, 2, 3+ sows and the entire cohort of sows respectively (quadratic; P < 0.01). In addition, the result of feed intake can be expressed as 2.65, 2.69, 2.69 and 2.68 g/Mcal based on analysis of SID-Lys:ME ratio. Litter weight gain was affected by dietary treatment for parity 3+ sows and the entire cohort (P < 0.01). Based on regression analysis, litter weight gain was maximized at 3.25 and 3.24 Mcal/kg of ME for parity 3+ (quadratic; P < 0.01) and the entire cohort (quadratic; P < 0.01). Similarly, the result of litter weight gain could be expressed as 2.65 and 2.66 g/Mcal of SID- Lys:ME ratio. Therefore, 3.25 Mcal/kg of ME was selected for Exp. 2 in which 150 sows (weighing 254.6 ± 7.3 kg and having an average parity of 3.4 ± 0.4) were allocated to one of five treatments in a completely randomized block design within parity (1, 2, and 3+). The experimental diets were formulated to contain 2.1, 2.4, 2.7, 3.0 or 3.3 g/Mcal of SID-Lys:ME ratio with all diets providing 3.25 Mcal/kg of ME. The diets were fed to the sows throughout a 28 day lactation. Sow body weight loss was affected by dietary treatment (parity 3+ sows, P = 0.02; entire cohort, P < 0.01) and by sow parity (P < 0.01). Litter weight at weaning and litter weight gain were affected by dietary treatment for parity 1, 2, 3+ sows and the entire cohort (P < 0.01) as well as by sow parity (P < 0.01). Plasma urea nitrogen (P < 0.01), creatinine (P < 0.01) and non-esterifide fatty acids (P = 0.04) were decreased as the SID-Lys:ME ratio of the diet increased. Insulin-like growth factor-1 (P = 0.02), estradiol (P < 0.01) and luteinizing hormone (P = 0.02) were increased as the SID-Lys:ME ratio in diet increased. Based on a broken-line model, the estimated SID-Lys: ME ratio to maximize litter weight gain was estimated to be 3.05 g/Mcal.     

The effect of the ratio of standardized ileal digestible lysine to metabolizable energy on growth performance, blood metabolites and hormones of lactating sows

ABSTRACT: A total of 335 lactating sows (Landrace × Large White) were used in two experiments to determine the optimum ratio of standardized ileal digestible lysine (SID-Lys) to metabolizable energy (ME) for mixed parity sows during lactation. In Exp. 1, 185 sows (weighing an average of 256.2 ± 6.5 kg and having an average parity of 3.4 ± 0.3) were allocated to one of six experimental diets in a completely randomized block design within parity groups (1, 2, and 3+). The experimental diets were formulated to contain 3.06, 3.16, 3.20, 3.25, 3.30 or 3.40 Mcal/kg of ME and each diet was fed to the sows throughout a 28 day lactation. All diets provided a similar SID-lysine level (0.86%). As a result, the diets provided a SID-Lys:ME ratio of 2.81, 2.72, 2.69, 2.65, 2.61 or 2.53 g/Mcal ME. Sow feed intake was significantly (P < 0.01) affected by the energy content of the diet as well as by sow parity. Using regression analysis, feed intake was shown to be maximized at 3.25, 3.21, 3.21 and 3.21 Mcal/kg of ME for parity 1, 2, 3+ sows and the entire cohort of sows respectively (quadratic; P < 0.01). In addition, the result of feed intake can be expressed as 2.65, 2.69, 2.69 and 2.68 g/Mcal based on analysis of SID-Lys:ME ratio. Litter weight gain was affected by dietary treatment for parity 3+ sows and the entire cohort (P < 0.01). Based on regression analysis, litter weight gain was maximized at 3.25 and 3.24 Mcal/kg of ME for parity 3+ (quadratic; P < 0.01) and the entire cohort (quadratic; P < 0.01). Similarly, the result of litter weight gain could be expressed as 2.65 and 2.66 g/Mcal of SID-Lys:ME ratio. Therefore, 3.25 Mcal/kg of ME was selected for Exp. 2 in which 150 sows (weighing 254.6 ± 7.3 kg and having an average parity of 3.4 ± 0.4) were allocated to one of five treatments in a completely randomized block design within parity (1, 2, and 3+). The experimental diets were formulated to contain 2.1, 2.4, 2.7, 3.0 or 3.3 g/Mcal of SID-Lys:ME ratio with all diets providing 3.25 Mcal/kg of ME. The diets were fed to the sows throughout a 28 day lactation. Sow body weight loss was affected by dietary treatment (parity 3+ sows, P = 0.02; entire cohort, P < 0.01) and by sow parity (P < 0.01). Litter weight at weaning and litter weight gain were affected by dietary treatment for parity 1, 2, 3+ sows and the entire cohort (P < 0.01) as well as by sow parity (P < 0.01). Plasma urea nitrogen (P < 0.01), creatinine (P < 0.01) and non-esterifide fatty acids (P = 0.04) were decreased as the SID-Lys:ME ratio of the diet increased. Insulin-like growth factor-1 (P = 0.02), estradiol (P < 0.01) and luteinizing hormone (P = 0.02) were increased as the SID-Lys:ME ratio in diet increased. Based on a broken-line model, the estimated SID-Lys:ME ratio to maximize litter weight gain was estimated to be 3.05 g/Mcal.     

Effect of liveweight and condition score of ewes at mating,and shearing mid-pregnancy,on birthweights and growth rates of twin lambs to weaning

AIMS: To determine the effects of liveweight and condition score of ewes at mating, and shearing mid-pregnancy, on birthweights and growth rates of twin lambs from birth to the time of weaning, and; to determine whether any effect of condition score is independent of liveweight.

METHODS: Romney ewes (n=435) which conceived within a 17-day mating period and successfully gave birth to and reared twin lambs to weaning were used. Ewes were managed during pregnancy so that their total liveweight increased at a level equivalent to the expected growth of the conceptuses. Approximately half of the ewes were shorn 70 days after the mid-point of mating, and the remainder were left unshorn, at which time they had 6-months' wool growth. All lambs were weighed within 12 h of birth and again at weaning.

RESULTS: There was a significant linear relationship (R²=0.99) between mean group liveweight and condition score of ewes at mating (difference of 7.3 kg per 1.0 unit condition score). Liveweight of ewes at mating had small but significant (p<0.05) positive effects on both birthweights and growth rates of twin lambs to weaning. Ewes that had condition scores of 3.5–4.0 (scale 0–5) at mating gave birth to significantly (p<0.05) lighter lambs than ewes that had condition scores <3.5. The condition score of ewes at mating was positively associated with growth rates of lambs, although this effect was largely explained by variation in the liveweight of ewes at mating.

Twin lambs born to ewes shorn mid-pregnancy were significantly (p<0.05) heavier at birth (by 0.4 kg) and at weaning (p<0.05) than those born to unshorn ewes. The heavier weaning weights of lambs born to ewes shorn mid-pregnancy were due to a heavier birthweights rather than increased growth rate.

CONCLUSIONS: Liveweight and condition score of ewes at mating had small positive effects on growth rates to weaning of twin lambs. Shearing mid-pregnancy increased birthweights and weaning weights of twin lambs. To achieve high weaning weights of twin lambs, farmers should ensure ewes attain high liveweights and condition scores at mating and shear mid-pregnancy. It is speculated that the effects of liveweight and condition score of ewes at mating on weaning weights of twin lambs would be greater than those observed in the present study under conditions in which nutrition of the dam is below optimum.