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1.
J.M. Everett-Hincks N. Lopez-Villalobos H.T. Blair K.J. Stafford 《Livestock Production Science》2005,93(1):51-61
The study was carried out on a commercial New Zealand sheep farm with high ewe reproductive rates and lamb survival produced through intensive selection in its Coopworth flock for maternal ability.Heritability and repeatability estimates were derived for ewe maternal behaviour score (MBS) and litter survival (LIS). Heritability estimates were derived for lamb survival as a trait of the lamb (LAS) for all lambs, for twin (LAS2) and for triplet (LAS3) lambs.MBS and LIS were measured on 1954 dams, for a maximum of four parities: 1997, 1998, 1999 and 2000. MBS was measured at tagging on a 5-point scale (1=poor, 5=excellent) when the dam's lambs were between 12 and 36 h old. The mean MBS in this study was 3.3 and increased with litter size. LIS was measured from birth to weaning. Mean litter survival was 83%. LIS increased significantly as MBS increased (P<0.01). LIS decreased as the size of the litter increased (P<0.01). Age of dam was a nonsignificant effect on LIS (P>0.05).LAS was measured from birth to weaning on 4171 Coopworth lambs. Mean LAS was higher for lambs born as twins compared to lambs born as singles and lowest for lambs born as triplets (P<0.01). LAS was lower for lambs born to dams aged 2 years. This effect was significant for all lambs, regardless of litter size at birth and for the triplet lamb data set (P<0.01). The effects of age of dam and sex of lamb on twin lamb survival were not significant (P>0.05). Ewe lamb survival rate was higher when compared to ram lambs in the full data set, however the relationship was reversed for the triplet lamb data set where ram lamb survival was greatest (P<0.01). LAS decreased as the MBS of its dam increased (P<0.01). The relationship was significant for lambs in the full data set and the twin data set (P<0.05).MBS and LIS were under minimal genetic control. The heritability and repeatability for MBS were both 0.09. The heritability and repeatability for dam LIS were 0.0 and 0.11. Heritability for LAS over all lambs attributed to direct effects was 0.14, while the heritability attributed to maternal effects was 0.11. The heritability for twin (LAS2) and triplet (LAS3) lamb survival differed. Heritability attributed to direct and maternal effects were 0.0 and 0.21, respectively, for twin lambs and 0.08 and 0.16, respectively, for triplets.The genetic correlation between maternal and direct effect for LAS was −0.74. It is possible that the genes that regulate physiological and biochemical processes for survival are incompatible with the genes that enhance ewe-lamb bonding. For example, the genes that regulate the physiological factors to reduce gregariousness at parturition may in fact be the same genes that encourage isolation in the neonate from its littermates and dam.There is minimal genetic variation in this flock for lamb survival and maternal traits. Low genetic variation suggests that selection will be ineffective, and that farmers must consider environment and management techniques for improving lamb survival. 相似文献
2.
This study examined the effect of blood sampling time (farm, transport, lairage) on welfare physiological indicators in two groups of different age/weight Manchega breed lambs (suckling vs light). Blood sampling time had a different effect on both types of lamb: In light lambs, there was an increase (P < 0.001) in red blood cells (RBC), haemoglobin, hematocrit and urea after lairage; but adrenaline, glucose and creatinine increased after transport. In suckling lambs, there were higher values of cortisol and potassium on the farm, both glucose and sodium increased after transport while adrenaline did after lairage. In general, significant differences (P < 0.001) were found between both types of lamb in the parameters analysed. Light lambs showed higher values of RBC, haemoglobin, hematocrit, adrenaline, noradrenalin, LDH, CK, sodium and lactate than younger animals in all blood sampling times. Only after lairage were urea and leucocytes lower (P < 0.05) in suckling than in light lambs, while cortisol was higher on the farm and lower after lairage in younger animals. 相似文献
3.
Calcium (Ca) requirement increase rapidly by pregnant ewes at late gestation as a result of high fetal growth. Furthermore, Ca deficiency results in poor growth and bone development in growing newborn lambs. The aim of this study was to evaluate the effect of calcium supplementation (Calcium carbonate–CC) and vitamin AD3E injection (75,000 IU/shot) to pregnant Awassi ewes at late gestation (− 45 days prepartum) on their mineral levels and performance of their newborn lambs. Forty pregnant Awassi ewes at late gestation (65 ± 6.1 kg) were selected before parturition (− 45 days; using hormonal sponges for estrus synchronization) and randomly divided to 4 dietary treatments. The treatments were: group 1 Control (1.4% CC); group 2 (2.4% CC); group 3 (1.4% CC + 2 shots vitamin AD3E at − 45 and − 21 days prepartum); group 4 (2.4% CC + 2 shots vitamin AD3E at − 45 and − 21 days prepartum). Blood samples were collected from ewes (− 45, 0 days prepartum: 30 and 60 days postpartum) and lambs (0, 30 and 60 days old). Average milk yield and samples were collected. Body weights of lambs were taken at birth, 30 and 60 days old. Blood serum and milk samples were prepared and analyzed by AAS for Ca, Mg, Co, Mn and Cu concentrations.Calcium concentrations in bloods serum of ewes, 0 and 60 days postpartum, and lambs at weaning (60 days old) from group 4 were significantly (P < 0.05) higher compared to other groups. No significant effect (P > 0.05) of treatment on Co, Mg and Cu in blood serum of ewes and lambs except for Cu concentration in ewes. Moreover, a significant increase (P < 0.01) in milk inorganic% (30 and 60 days samples) in ewes from group 2 when compared with other groups. The average milk yield (AMY) of ewes from group 2 and 4 at late stage of lactation (45–60 days) were significantly higher (P < 0.05) compared to groups 1 and 3. In addition, Ca% in colostrums samples from ewes in groups 2 and 4 were significantly higher (P < 0.01). The average daily gain (ADG) and total body gain for lambs up to weaning (60 days old) were significantly higher (P < 0.05) in groups 1 and 2 compared with the other groups.In conclusion, increasing level of Ca intake in feed of Awassi ewes at late gestation, with or without vitamin AD3E injections, improve the calcium concentration in colostrums and blood serum of ewes and their lambs without negative effect in their health and performance. 相似文献
4.
Thirty Awassi ram lambs were used to study the effects of slaughter weight on carcass characteristics. Lambs were slaughtered at three different live weights (20, 30, and 40 kg). Empty body weight, hot and cold carcass weights and non-carcass components increased (P < 0.001) at a steady rate between all slaughter weights. Body length, leg length, maximum shoulder width, width behind shoulders and gigot width increased (P < 0.001) as slaughter weight increased from 20 to 40 kg. Linear dimensions measured on the surface of the M. Longissimus also increased (P < 0.001) with increasing slaughter weight. The ratio between width and depth of the longissimus muscle decreased (P < 0.01) at a steady rate between 20 and 40 kg indicating that the muscle increased more in depth than width. Dressing-out percentage was higher (P < 0.001) for lambs slaughtered at 30 kg live weight compared to other weights. Total lean and total bone decreased (P < 0.05) as a percent of cold carcass weight while total fat, subcutaneous and intermuscular fat percentages increased (P < 0.05) with increasing weight. Subcutaneous fat percentage was not affected by increasing body weight between 20 and 30 kg. Intermuscular fat percent was higher in all cuts except the leg where subcutaneous fat % was higher. Muscle to bone ratio increased (P < 0.001) while muscle to fat ratio decreased (P < 0.001) with increasing body weight in the four major cuts and the whole carcass. In conclusion, slaughtering Awassi ram lambs at weights up to 30 kg resulted in higher dressing-out percentage and better carcass characteristics than ram lambs slaughtered at heavier weights. 相似文献
5.
The ARR allele of the prion protein gene is associated with resistance to classical scrapie, while the ARQ allele is associated with susceptibility. The objective of this study was to estimate the effect, on lamb growth and carcass traits, of replacing an ARQ allele with an ARR allele. Pedigree rams (22 Suffolks, 18 Texels and 18 Charollais) were sourced in pairs, from the same flock (by the same sire where possible), with one member being ARR/ARR and the other being ARQ/ARQ and these rams were progeny tested through single-sire mating in six flocks. Effects of ram genotype on reproductive performance of ewes and on growth and carcass traits of progeny were estimated using mixed model procedures with sire as a random effect. Ram genotype had no effect on litter size at birth or on lamb survival as measured by the number of lambs reared. The differences between the performance of progeny by ARR/ARR and ARQ/ARQ sires provided an estimate of the effect of substituting an ARR allele for an ARQ allele. This allele substitution had no effect on birth weight, growth rate, weight at 5 or 14 weeks, weight or ultrasonic fat depth at 120 days of age or on carcass classification traits (conformation, fatness) for the Suffolk, Texel or Charollais breeds. Substituting an ARR allele for an ARQ allele had a negative effect on ultrasonic muscle depth at 120 days for the progeny of Suffolk rams (P = 0.01) but had a positive effect on ultrasonic muscle depth at 120 days for the progeny of Charollais rams (P = 0.02). The ARR substitution effect was negative for slaughter age in the Suffolk (P < 0.05) and positive for carcass weight in Texel progeny (P < 0.05). The magnitude of these effects was quite small, however, and the overall results support the hypothesis that substituting an ARR allele for an ARQ allele has no important negative effect on lamb growth or carcass traits in any of the breeds examined. 相似文献
6.
An experiment was conducted to evaluate the effect of a Ca salt supplement on lactating Awassi ewes and their lambs. Ninety Awassi ewes (average BW = 55 kg ± 1.13) were allocated into three treatment groups of 30 each; 0%, 3%, or 5% Ca salt supplemented groups. The experiment started at lambing and lasted for 60 d. During this period, milk production and composition, final body weights, total feed intake, serum cholesterol and triglycerides, weaning weights of lambs, and milk fatty acid profile were tested. Milk production and energy corrected milk increased (P < 0.05) with Ca salt level in the diet. Milk fat content was higher (P < 0.05) at 3% treatment group compared to 0% and 5% treatment groups. However, no differences were detected in content of crude protein and total solids, and milk energy value. Milk fat yield (g/d) increased (P < 0.05) as Ca salt in the diet increased. Final body weight was higher (P < 0.05) for 5% group when compared to the 0% group with no differences between the 3% group when compared to 0% and 5% groups. No differences were observed in feed intake of ewes. Metabolizable energy intake was greater (P < 0.05) for the 3% and the 5% treatment groups when compared to the 0% treatment group. Feed to milk ratio increased (P < 0.05) when increasing the level of Ca salt in the diet. Serum cholesterol was greater (P < 0.05) in the 5% treatment group than the 0% and 3% treatment groups for ewes and lambs. Serum triglyceride was similar among treatment groups in ewes whereas serum triglyceride was greater (P < 0.05) for lambs in 5% treatment group than 0% and 3% treatment groups. However, serum triglyceride was similar in ewes among treatment groups. Weaning weights and average daily gain of male lambs were higher (P < 0.05) in lambs fed Ca salt (3% and 5%) when compared to 0% treatment group. No differences were detected in weaning weights and average daily gain of female lambs among treatment groups. However, milk conversion ratio was better (P < 0.05) for the 5% group lambs than the 0% and 3% treatment groups. Ca salt reduced (P < 0.05) short and medium-chain milk fatty acids and increased (P < 0.05) content of long chain and unsaturated ones. These results of this indicate that Ca salt supplementation can improve milk production of lactating ewes, the growth rate of their lambs, and produce healthy quality value milk. 相似文献
7.
Observations of behaviour at parturition of prolific Booroola Merinos were recorded for 48 single-, 77 twin-, 56 triplet- and 14 quadruplet-bearing ewes. Average lamb birthweight decreased as litter size increased. Single lambs were on average 2 kg heavier than quadruplet lambs. Within twin and triplet litters the period of abdominal straining during labour was significantly shorter for later-born lambs than for the first-born lamb. Single-born lambs were presented longer at the ewe's vulva than lambs from other litters. The first-born of twins was presented longer at the ewe's vulva than the second-born lamb. Ewes 2 years of age were slower to stand after birth and to begin to groom lambs than adult ewes. The ewe was not selective in grooming members of a litter. The first-born lamb of single and twin litter sizes was quicker to stand and suck than the first-born lamb of triplet and quadruplet litters. The second-born lamb of twins was quicker to suck than the second-born of other litter sizes. Birth order did not affect the time taken to suck. Regardless of litter size, heavier lambs were quicker to stand and suck resulting in a greater chance of survival, and an increase of 1 kg in birthweight resulted in a 28% increase in survival. Survival of lambs was significantly affected by their behaviour after adjustment for birthweight. With an increase of 1 min in the intervals from delivery to when the lamb first attempts to stand, stands or attempts to find the udder its chances of survival decreased by about 1%. It was concluded that birthweight was the major component affecting lamb survival in prolific Booroola Merino sheep. 相似文献
8.
A.H. Barkawi Amal K. El-Asheeri Y.M. Hafez M.A. Ibrahim M.M. Ali 《Livestock Science》2009,124(1-3):9-14
Ten male lambs of each of Rahmani (R) and Ossimi (O) were used to study the growth and carcass characteristics within their first year of age (360 days). After suckling period (4 months), lambs were fed on the regular ration. During the course of the experiment, body weight (BW) was recorded monthly accompanied by blood sampling to determine IGF-I. Four lambs from each breed were slaughtered at 270 and 360 days of age, and Longissimus lumbarum (L. lumbarum) at the 9th, 10th and 11th ribs and Biceps femoris (B. femoris) muscles were separated to be used for chemical analysis and histological study.Breed had no effect on the growth curve of the two studied breeds. Chemical analysis indicated that (O) had higher fat (0.9%, P < 0.0001) and lower (0.3%, P < 0.01) moisture compared to (R), with no difference in protein and ash contents. The concentration of IGF-I was almost similar in both breeds up to day 270 of age, and then it was higher in (R). Number of fibers per bundle was higher (P < 0.05) in (O) than in (R) by 6.1%, while, the other histological traits were similar in the two studied breeds.Chemical analysis indicated that lambs slaughtered at 360 days of age had lower (0.7%, P < 0.0006) moisture and higher fat (17.3%, P < 0.0001) compared to day 270. Up to day 270 of age, IGF-I concentration was < 500 ng/ml before increasing to > 500 ng/ml up to the end of the experiment. No effect of age was observed on the studied histological traits.L. lumbarum muscle contained higher protein (4.2%, P < 0.0001), fat (104%, P < 0.0001) and ash (10%, P < 0.001), while moisture was less (5.6%, P < 0.0001) compared to B. femoris muscle. B. femoris muscle was higher (P < 0.0001) in number and diameter of fibers, bundle and stroma sectional areas relative to L. lumbarum by 38.2, 78.8, 53.2 and 23.8%, respectively. 相似文献
9.
Jose M Ramos-Nieves Sarah L Giesy Molly M McGuckin Yves R Boisclair 《Journal of animal science》2020,98(12)
Intrauterine growth restriction (IUGR) is often observed in one of the fetuses carried by well-fed prolific ewes. This condition is the result of an insufficient placental size to cover the nutritional needs of the fetus during the near exponential growth phase of the last trimester. After birth, these IUGR offspring have an elevated appetite and lower maintenance energy requirements, suggesting dysregulation of homeostatic systems governing energy metabolism. It is also unknown whether the consequent increase in fatness occurs similarly in both visceral and carcass fractions. To address these questions, lambs differing in birth size (BS, IUGR vs. Normal, 2.6 ± 0.05 vs. 4.2 ± 0.07 kg, P < 0.001) were offered unlimited amounts of a low fat [LF; 22% of dry matter (DM)] or a high fat (HF; 38% of DM) milk replacer and slaughtered on day 14 of postnatal age (n = 7 to 8 for each BS × Diet); a second group of IUGR lambs (n = 3 for each diet) was slaughtered when they reached 8.5 kg, corresponding to the weight of Normal lambs on day 14. When normalized to body weight (BW), the DM and energy intake of IUGR lambs were higher than those of Normal lambs over the first 14 d of life (BS, P < 0.01), but contrary to expectations, the HF diet did not exacerbate these effects of the IUGR condition. Intrauterine growth restricted lambs had increased viscera fat with both diets (BS and Diet, P < 0.05) but increased carcass fat only with the LF diet (BS × Diet, P = 0.08); the fatness promoting effect of the IUGR condition was increased in both body fractions when lamb groups were compared at the fixed BW of 8.5 kg. A subset of metabolic hormones was analyzed, including the metabolic rate-setting hormone thyroxine (T4) and its possible positive regulator leptin. Plasma T4 was lower in IUGR than in Normal lambs at birth (P < 0.05) but then disappeared by day 7 of postnatal life (BS × Day, P < 0.01). On the other hand, the HF diet had no effect on plasma T4 over the first 3 d but caused an increase, irrespective of BS by day 11 (Diet × Day, P < 0.001). Plasma leptin increased with dietary fat and time (P < 0.06) but bore no relation to the effects of BS or Diet on plasma T4. These data show that IUGR and Normal lambs are similarly unable to adjust caloric intake in early life and that the fatness promoting effects of the IUGR condition are more pronounced in the viscera than in the carcass. These data also reveal dynamic regulation of plasma T4 by BS and Diet in neonatal lambs. 相似文献
10.
This study investigated the effects of dietary δ-aminolevulinic acid (ALA) on growth performance, nutrient digestibility, blood parameters and whether ALA improved the immune response of weanling pigs challenged with Escherichia coli lipopolysaccharide (LPS). Eighty pigs (body weight = 7.21 ± 0.51 kg) were allotted to four dietary treatments, with four pens per treatment and five pigs per pen. Basal diets were supplemented with 0, 5, 10, and 15 mg/kg ALA (as-fed basis) and fed for 35 days. At the end of the feeding period, 10 pigs were selected from both the 0- and 10-mg/kg ALA treatment groups; five were injected i.p. with LPS (50 μg/kg BW) and the other five pigs with an equivalent amount of sterile saline, resulting a 2 × 2 factorial arrangement. Blood sample and rectal temperature data were collected at 0, 2, 4 and 12 h after challenge. Growth performance was not affected by dietary treatments over the total experimental period. However, dry matter (DM) and nitrogen (N) digestibility was improved in the 15-mg/kg ALA treatment group at day 35 (P < 0.05). Serum hemoglobin (Hb) and iron levels were also increased, with the 10-mg/kg ALA treatment showing the highest concentration (P < 0.05). On day 35, red (RBC) and white blood cell (WBC) counts were elevated, with the 5- and 10-mg/kg ALA treatments having the highest counts (P < 0.05). During challenge, LPS injection elevated rectal temperature at 2 and 4 h postchallenge (P < 0.05). Plasma cortisol concentration was also increased by LPS injection at 2 and 4 h postchallenge and an ALA-alleviating effect was evident at 2 h postchallenge (P < 0.01). Concentration of plasma insulin-like growth factor-I (IGF-I) was increased in the ALA-supplemented treatments at 2 h postchallenge (P < 0.05). LPS injection increased plasma tumor necrosis factor-α (TNF-α) concentrations at 2, 4 and 12 h (P < 0.01), while an ALA-alleviating effect was observed at 2 and 4 h postchallenge (P < 0.05 and P < 0.10, respectively). Challenge with LPS decreased WBC counts at 2 and 4 h postchallenge (P < 0.01). At 12 h postchallenge, RBC, WBC and lymphocyte counts were affected by LPS challenge, while an ALA effect was only observed on WBC count (P < 0.05). In conclusion, dietary supplementation of ALA in weanling pigs can improve DM and N digestibilities, and iron status and have a beneficial effect on the immune response during inflammatory challenge. 相似文献
11.
Effect of sex and feeding system on feed intake, growth, and meat and carcass characteristics of fattening Assaf lambs 总被引：2，自引：0，他引：2
A.B. Rodríguez R. Bodas N. Prieto R. Landa A.R. Mantecn F.J. Girldez 《Livestock Science》2008,116(1-3):118-125
The effect of feeding system and sex on intake, growth and carcass and meat characteristics of Assaf fattening lambs was studied. Twenty four weaned Assaf lambs, half males and half females were used. After an adaptation period, lambs were randomly assigned to one of the two feeding systems studied. Control lambs received ad libitum commercial concentrate (70% barley, 22% soybean meal, 4.8% wheat, 0.5% bicarbonate, 2.7% mineral–vitamin premix) and barley straw. Free Choice lambs had ad libitum and separate access to whole barley grain and a protein supplement (73.3% soyabean meal, 16% wheat, 1.7% bicarbonate, 9% mineral–vitamin premix). Lambs were slaughtered at 25 kg LBW. Feed intake was not significantly affected by sex (P > 0.05) but Free Choice lambs showed higher dry mater intake than the Control lambs. Nevertheless, only males from the Free Choice group showed an improvement in feed efficiency rate (P < 0.05) and average daily gain (P < 0.01) relating to the Control lambs. Neither feeding system nor feeding system × sex interaction significantly affected non-carcass weight, fat depots, cold carcass weight, dressing percentage, main proportions of commercial cuts and meat characteristics (P < 0.05). As it was expected, female lambs showed a lower average daily gain and a higher feed conversion efficiency than male lambs (P < 0.001) which was related to a greater fat deposition. Meat characteristics were unaffected by sex, with the exception of longissimus lumborum fat content, which was higher in female lambs.The present results suggest that Free Choice feeding system might be suitable for intensively reared male lambs since improvements in daily weight gain and feed conversion rate were achieved, with no adverse effect on carcass and meat quality. Despite the selected diet of both, males and females, did not differ in the crude protein content, the use of Free Choice feeding system for female lambs did not improve performance compared to the Control group. 相似文献
12.
Willem Sauer Miguel Cervantes Jorge Yanez Benedicto Araiza Gordon Murdoch Adriana Morales Ruurd T. Zijlstra 《Livestock Science》2009,122(2-3):162-168
The objective of this study was to determine the effect of dietary inclusion of benzoic acid on utilization of the macrominerals Ca, P, Mg, K, Na, and Cl in growing pigs. Eighteen barrows, initial BW of 28 ± 1.7 kg, were assigned to 3 diets: a basal diet based on barley, wheat, soybean meal, corn, and field pea and formulated to contain 9.31 MJ NE kg− 1 and 8.84 g− 1 kg standardized ileal digestible lysine, or the basal diet containing 10 or 20 g kg− 1 benzoic acid by replacing tapioca starch. The pigs were fed the experimental diets a rate of 2.7 times the maintenance requirement for ME for 21 days. Faeces and urine were collected quantitatively from days 11 to 21, and blood and plasma was collected on days 1, 10, and 21. On day 21, the pigs were killed and the left femur was removed. Benzoic acid linearly decreased (P = 0.001) the urine pH from 7.32 to 5.32, and quadratically increased (P < 0.05) blood pH on day 21. Benzoic acid linearly increased (P < 0.05) the apparent total tract digestibility (ATTD) of Ca, P, and Na from 65 to 72%, 46 to 55%, and 78 to 90%, respectively, linearly decreased (P < 0.05) the ATTD of Cl from 94 to 93%, and did not affect the ATTD of Mg and K. Benzoic acid linearly increased (P < 0.05) the retention of Ca, P, and K from 58 to 67%, 46 to 54%, and 31 to 38%, respectively, linearly decreased (P < 0.05) the retention of Na and Cl from 57 to 48% and 75 to 44%, respectively, and did not affect retention of Mg. On day 21, benzoic acid linearly increased (P = 0.001) plasma P and quadratically increased (P < 0.05) plasma K or tended to increase (P = 0.05) plasma Na. Benzoic acid linearly reduced (P < 0.05) the concentration of ash in femur but not the amount of ash, reduced (P < 0.05) the concentration of Ca and Cl in femur ash, and linearly increased (P < 0.05) the concentration of P in femur ash. In summary, benzoic acid increased the utilization of dietary Ca, P, and K, did not affect the utilization of dietary Mg, and reduced the utilization of dietary Na and Cl. During swine feed formulation, effects of benzoic acid on macromineral utilization should be considered to ensure that macromineral requirements are met and not exceeded following benzoic acid supplementation. 相似文献
13.
Barazandeh A Moghbeli SM Vatankhah M Hossein-Zadeh NG 《Tropical animal health and production》2012,44(4):929-934
Survival records from 1,763 Kermani lambs born between 1996 and 2004 from 294 ewes and 81 rams were used to determine genetic
and non-genetic factors affecting lamb survival. Traits included were lamb survival across five periods from birth to 7, 14,
56, 70, and 90 days of age. Traits were analyzed under Weibull proportional hazard sire models. Several binary analyses were
also conducted using animal models. Statistical models included the fixed class effects of sex of lamb, month and year of
birth, a covariate effect of birth weight, and random genetic effects of both sire (in survival analyses) and animal (in binary
analyses). The average survival to 90 days of age was 94.8%. Hazard rates ranged from 1.00 (birth to 90 days of age) to 1.73
(birth to 7 days of age) between the two sexes indicating that male lambs were at higher risk of mortality than females (P < 0.01). This study also revealed a curvilinear relationship between lamb survival and lamb birth weight, suggesting that
viability and birth weight could be considered simultaneously in the selection programs to obtain optimal birth weight in
Kermani lambs. Estimates of heritabilities from survival analyses were medium and ranged from 0.23 to 0.29. In addition, heritability
estimates obtained from binary analyses were low and varied from 0.04 to 0.09. The results of this study suggest that progress
in survival traits could be possible through managerial strategies and genetic selection. 相似文献
14.
Fourty-eight Churra Tensina single male lambs were used to evaluate the effect of different feeding systems on carcass composition and predict the carcass tissue composition from joint composition and carcass measurements. Four treatments were studied: GR, unweaned lambs continuously grazing with ewes; GR + S, the same as the previous group, but lambs had free access to concentrate; DRL-GRE, lambs remained indoors with free access to concentrate and ewes grazed for 8 h/day, thereafter remaining with lambs; and DRL, lambs and ewes were kept in confinement, they had free access to concentrate and dry unifeed respectively. In the DRL-GRE and DRL groups lambs were weaned when 45 days old. Lambs were slaughtered at 22–24 kg live weight. Commercial joints from the half left carcass were obtained, recorded and dissected to determine carcass tissue composition.The feeding system had an effect on the proportion of the carcass tissue composition. GR treatment showed higher muscle (M) (p < 0.05) and bone (B) (p < 0.001) percentages, and a lower total fat (F) percentage (p < 0.001) than the rest of treatments. Hence it revealed higher M/F (p < 0.01) and lower M/B (p < 0.05) and subcutaneous fat/intermuscular fat ratios (SF/IF; p < 0.001). Carcass composition predictions were more accurate for grams than for percentages. In predictions from joint composition, pelvic limb was the most accurate joint for grams (R2 = 0.84, R2 = 0.68, and R2 = 0.77 for muscle, bone, and fat, respectively) as well as for percentage (R2 = 0.65, R2 = 0.56, and R2 = 0.73 for muscle, bone, and fat, respectively). Predictions from carcass measurements were greater in muscle and fat grams (R2 = 0.87 and R2 = 0.86 for muscle and fat, respectively) than in percentage (R2 = 0.58 and R2 = 0.73 for muscle and fat, respectively). Equations to predict carcass tissue that include carcass measurements are a simple method to assess accurately saleable muscle yield from different lamb feeding systems without involving carcass damage. 相似文献
15.
Genetic homogenisation of birth weight in rabbits: Indirect selection response for uterine horn characteristics 总被引：1，自引：1，他引：0
G. Bolet H. Garreau T. Joly M. Theau-Clement J. Falieres J. Hurtaud L. Bodin 《Livestock Science》2007,111(1-2):28-32
A divergent selection experiment on within-litter homogeneity of birth weight in rabbits was carried out at the INRA experimental farm at Auzeville. The two lines were created by selecting breeding does and bucks from the female strain AGP22 bred at the Grimaud Frères Sélection Company. This involved a new model incorporating a genotypic value for the mean of individual birth weight and a genotypic value for the environmental variance. This new “trait” was modelled in the usual infinitesimal framework, giving estimated breeding values for environmental variability. There was a favourable selection response with a significant difference in within-litter standard deviation of birth weight between the lines selected for increasing (HOM) or decreasing (HET) homogeneity. At the end of the third generation, 31 females from the HOM line and 33 from the HET line were sacrificed to collect the uterine horns and measure their initial length (L1) and their length after elongation with a weight of 50 g (L2) and then 70 g (L3). The length in the homogeneous line was significantly greater, whatever the weight (L1: + 1.3 cm, P = 0.02; L2: + 2.8 cm P < 0.001; L3: + 4.2 cm, P < 0.001). The absolute and the relative elongations were significantly higher in the HOM line. There was no significant effect of the line on the number of ova shed, the weight of the ovary, or the weight of the uterine horns. It is concluded that the divergence between lines for the within-litter homogeneity of birth weight is at least partly due to the characteristics of the genital tract, i.e. the length and capacity for elongation of the uterine horn. 相似文献
16.
The effect of dietary barley level on volatile fatty acid concentration and manure ammonia emissions in finishing pigs 总被引：2，自引：0，他引：2
An experiment was conducted to investigate the linear and quadratic effects of barley on volatile fatty acid (VFA) profile and manure ammonia emissions in pigs. Sixteen boars (66 kg) were assigned to one of four treatments (n = 4): (T1) 0 g/kg barley (control), (T2) 222 g/kg barley, (T3) 442 g/kg barley and (T4) 666 g/kg barley. Barley was substituted for wheat. The diets were formulated to contain similar concentrations of digestible energy and lysine, soya oil was adjusted to maintain net energy. Increasing barley levels caused a linear decrease in colonic (P < 0.01) and caecal pH (P < 0.001). Total caecal VFA and propionic acid were affected by dietary barley level (quadratic, P < 0.05). There was a linear decrease in the proportion of acetic acid (P < 0.001), isobutyric acid (P < 0.01), isovaleric acid (P < 0.05) with increasing levels of barley in both the caecum and colon. There was a linear increase in the proportion of propionic acid (P < 0.001) and butyric acid (P < 0.05) with increasing barley in the colon. Barley based diets had a lower ammonia emission from 96 to 240 h (P < 0.05) and from 0 to 240 h (P < 0.05) than the wheat based diet. In conclusion, a high level of barley is required to reduce offensive branch chained VFAs. 相似文献
17.
Marina Vrani&#x; M. Kneevi&#x; K. Bo&#x;njak J. Leto G. Per
ulija I. Mati&#x; 《Livestock Science》2008,114(1):84-92
The objective of this experiment was to study the effects of interactions between medium quality grass silage (GS1) and maize silage (MS) as well as between low-quality grass silage (GS2) and MS on ad libitum intake, digestibility and N retention in wether sheep. Two grass silages (GS1 and GS2) were ensiled in round bales, without additives, from the primary growth of orchard grass (Dactylis glomerata L.) harvested at two different maturity stages. The study consisted of seven feeding treatments incorporating GS1, GS2 and MS fed alone and forage mixtures of GS1 and MS as well as GS2 and MS (67:33% and 33:67%, respectively, DM (dry matter) basis).Delayed harvesting lowered (P < 0.05) the crude protein (CP) concentration in GS2 compared to GS1. The DM content (g kg− 1 fresh sample) and starch concentration (g kg− 1 DM) of MS were 264 and 211, respectively.Inclusion of MS in the GS1-based ration had positive linear effects on CP and starch digestibility (P < 0.05 and P < 0.01, respectively) and N intake (P < 0.01) while a negative effect on neutral detergent fibre (NDF) and acid detergent fibre (ADF) digestibility (P < 0.05 and P < 0.01, respectively). A positive associative response of GS1 and MS was observed for DM ad libitum intake (g kg− 1 M0.75 day− 1) (quadratic, P < 0.05), CP digestibility (quadratic, P < 0.01), N intake (quadratic, P < 0.01) and N balance (quadratic, P < 0.05). Inclusion of MS into the GS2-based ration had a positive linear effect on the ration fresh matter ad libitum intake (kg day− 1 and g kg− 1 M0.75 day− 1) (P < 0.01 and P < 0.001, respectively), NDF ad libitum intake (kg day− 1 and g kg− 1 M0.75 day− 1) (P < 0.01), digestibility of DM (P < 0.01), organic matter (OM) (P < 0.01), ADF (P < 0.05), starch (P < 0.001), digestibility of OM in DM (D-value) (P < 0.001), and N intake (P < 0.01). Positive associative effects of GS2 and MS were observed on all the intake and digestibility parameters measured, N intake (quadratic, P < 0.001) and N balance (quadratic, P < 0.05). It was concluded that, as expected, a positive associative response of GS2 and MS was recorded for all the measured parameters while that of GS1 and MS for a limited number of parameters, probably due to lower quality of MS (lower starch concentration) than required for improved utilization of the GS1-based ration. 相似文献
18.
The objective of this experiment was to examine the effects of feeding a vitamin A deficient diet (VAF) to pigs at different times on day 100 of foetal and days 0, 1 and 2 of neonatal development. Three treatments included a control (n = 12), VAF for 100 days before mating and during the first month of pregnancy (n = 13; VAF–control), and VAF during the oestrous cycle before mating and throughout pregnancy (n = 13; control–VAF). On day 100 of pregnancy, maternal liver and plasma retinol concentrations were reduced in both groups of gilts fed a vitamin A free diet compared to controls (P < 0.001 and P < 0.01, respectively). Day 100 foetal liver retinol concentrations were not affected by dietary treatment, whereas foetal plasma concentrations were higher in foetuses carried by gilts fed the VAF–control diet (P < 0.05). Piglets born to mothers fed the control–VAF, but not the VAF–control diet had consistently lower hepatic and plasma liver retinol concentrations (P < 0.05). Moderate reductions in maternal vitamin A at either stage of pregnancy did not affect pregnancy rate, litter size, progesterone secretion or the allometric relationships between foetal or neonatal organ and total body size. Reduced vitamin A during conception and early pregnancy, but not during later pregnancy, was associated with increased within-litter uniformity in birth weight (P < 0.05) and a tendency for fewer low birth weight piglets, but this needs to be confirmed in a greater number of sows. The mechanism underlying this effect is not known, but appears to not involve an alteration in progesterone production. 相似文献
19.
Energy balance, milk production and reproduction in grazing crossbred cows in the tropics with and without cereal supplementation 总被引：2，自引：0，他引：2
Carlos Aguilar-Prez Juan Ku-Vera Fernando Centurin-Castro Philip C. Garnsworthy 《Livestock Science》2009,122(2-3):227-233
The aim of this work was to study the effect of parity order and reproductive management systems on rabbit production performance. A total of 73 rabbit does (I group) were submitted to a 35-day intensive rhythm [artificial insemination (AI) on day 4 post-partum (pp) and weaning at 25 days of lactation], and 108 rabbit does (SI group) were submitted to a 42-day semi-intensive rhythm (AI on day 11 pp and weaning at 35 days of lactation) during 9 months. Primiparous does had the lowest live body weight at parturition (P < 0.0001) and at 21 days of lactation (P < 0.0001). They also had lower milk production (P < 0.0001) than does with later parities. I group animals needed a higher number of AI than SI group to become pregnant (1.70 ± 0.03 vs. 1.39 ± 0.03; P < 0.0001: especially after the third). Prolificacy was not affected by the management system. Parturition interval (PI) was longer than expected in both groups [56.0 ± 1.4 and 50.9 ± 1.38 days in I and SI groups, respectively (P < 0.05)]. Mean productivity, estimated as number of weaned rabbits per female and year, was 12 kits higher in rabbit does of the SI group (P < 0.05). From the third parturition onward, an increase in live body weight of kits at different ages was observed. At 21 (P < 0.05) and 25 days of age (P < 0.01), kits from the I group rabbit does weighed more than those from the SI group; however, the latter showed a higher weight at 35 (P < 0.05) and 60 days of age (P < 0.05). Rabbit does with two or three parturitions had higher litter size at 21 and 25 days of age (P < 0.0001 and P < 0.001, respectively). Kit mortality between 21 and 25 days of age and between 35 and 60 days of age was not affected by treatments but was higher in the I group between 25 and 35 days (18.2 vs. 5.03% in the I and SI groups, respectively; P < 0.0001) and as age of does increased (P < 0.05). In light of these results, we could conclude that long term doe reproductive performance is negatively affected and litter viability decreased when using intensive compared to a semi-intensive reproductive management. 相似文献
20.
Cortisol and catecholamine levels in lambs: Effects of slaughter weight and type of stunning 总被引：1，自引：1，他引：0
The objectives of this study were (1) to determine the levels of cortisol (C) and catecholamines (adrenaline, A, and noradrenaline, NA) in lambs (n = 45) at different age/slaughter weight [suckling vs light], in farm (T0), after transport (T1), in the slaughterhouse after lairage (T2) and (2) to study the effect of the type of stunning, electrically vsgas, on C, A and NA values, in both groups of slaughter weight. Levels of C and A at T0 and T1 were similar in both groups (suckling and light), but NA was higher in suckling lambs as in T0 (P < 0.05) as in T1 (P < 0.01). Levels of all hormones were higher in suckling lambs at T2 (P < 0.05, P < 0.001 and P < 0.01, for C, A and NA, respectively). In general, the younger group showed higher values of C, A and NA than the light group after stunning, with significant differences on A and C in the electrically stunned lambs (P < 0.001, P < 0.05 respectively) and on A in the gas stunned group (P < 0.01). Only in the light group, levels of A were higher (P < 0.01) in the electrically than in the gas stunned group. In conclusion CO2 could be a good method to stun lambs because stress indexes were similar to levels found in electronarcosis method. 相似文献