共查询到20条相似文献,搜索用时 46 毫秒
1.
B. Manyuchi H. P. R. Tawonezvi R. M. Chiwara 《Tropical animal health and production》1991,23(2):115-125
Performance of the Dorper and Mutton Merino breeds and their crosses was assessed from 1,305 ewe and 1,453 lamb records from six lambing seasons. Dorper and Mutton Merino were mated in all combinations under an accelerated lambing system and crossbred females were mated to Suffolk rams. The Dorper and Mutton Merino breeds were not significantly different for fertility, pre-weaning lamb growth and survival. Suffolk sired lambs from crossbred ewes grew rapidly and were heaviest at birth and at weaning. They also survived better than lambs from the other breeding groups and this contributed to the higher weaning rate (P less than 0.05) in crossbred ewes. Weight of weaned lambs per ewe exposed to the ram per season was 12% higher (P less than 0.05) in the Dorper than the Mutton Merino ewes. However lifetime production was 28% higher (P less than 0.01) in Mutton Merino ewes due to significantly superior longevity. Crossbred ewes were highly productive. Individual heterosis was not significant but estimates were positive for most traits. Growth rate and survival of lambs increased as age of dam increased to 48 and 40 months respectively. Lambs born to previously non-lactating ewes were heavier and survived better than lambs born to ewes lactating in the previous season. Lambs born and reared as singles were 25% heavier at birth (P less than 0.001) and 52% heavier at weaning (P less than 0.001) than those born and reared as twins. Male lambs grew faster and were 7% heavier at weaning than females (P less than 0.001). 相似文献
2.
AIM: To quantify the effects of clinical Johne's disease on the performance of Romney, Merino and Merino x Romney-cross ewes. METHODS: The performance of ewes was compared using eight birth cohorts (1971-1978). Merino and Merino-cross genotypes included New Zealand Merino and Australian Superfine Merino sources. Intensive monitoring of Johne's disease was undertaken over the production years 1975-1982. Positive diagnostic evidence of Johne's disease was established post mortem from lesions of granulomatous enteritis associated with high numbers of acid-fast bacilli. Over years, data on a total of 2,341 Romney ewes and 1,292 Merino and Merino x Romney-cross ewes were recorded, consisting of annual records of liveweight (LWT), greasy fleece weight (FWT), number of lambs born per ewe per year (NLB), and lifetime productivity of ewes. RESULTS: A total of 82 (3.5%) Romney ewes and 62 (4.8%) Merino and Merino x Romney-cross ewes were diagnosed with clinical Johne's disease over the 8-year monitoring period, equivalent to 0.9% and 1.2% annual cases for these breeds, respectively, of the ewes present at mating. The percentage of clinical cases (p<0.04) and the age at death from Johne's disease (p<0.02) were lower for Romneys than for Superfine Merinos. The mean age of death from Johne's disease was 3.41 (standard error (SE) 0.06) years, lower than the mean disposal age from the flock of 5.03 (SE 0.02) years for clinically normal ewes (p<0.001). In their final year of production, ewes with clinical Johne's disease had lower LWT by 5.3 kg (10.5% of the mean; p<0.001), lower annual FWT by 0.54 (SE 0.10) kg (14.2%; p<0.001), fewer NLB by 0.15 (SE 0.07) lambs (13%; p<0.05), and lower litter weaning weights by 3.6 (SE 1.3) kg (15%; p<0.01) compared with clinically normal ewes. The size of the production losses associated with Johne's disease depended on the age to which ewes survived. Considering all production years of ewes (up to 8 years), the total weight of lambs weaned by ewes with clinical Johne's disease was 30.9 (SE 3.4) kg lower (46%; p<0.001) than the total from clinically normal ewes. CONCLUSIONS: Clinical Johne's disease led to significant losses in LWT, FWT, NLB, and in the lifetime production of ewes, amounting overall to a 46% reduction in productivity (p<0.001). CLINICAL RELEVANCE: Productivity losses from clinical cases of Johne's disease would be of considerable economic importance in flocks with a high incidence of the disease. The lack of good diagnostic tests for Johne's disease in the live animal, and the lack of active surveillance programmes, has made it difficult to establish the true prevalence of Johne's disease in sheep flocks in New Zealand, and its economic consequences. 相似文献
3.
André M. Almeida Tanya Kilminster Tim Scanlon Susana S. Araújo John Milton Chris Oldham Johan C. Greeff 《Tropical animal health and production》2013,45(6):1305-1311
Seasonal weight loss (SWL) is the most pressing constraint in ruminant production systems in tropical climates. SWL is controlled using supplementation, which is costly and difficult to implement in extensive systems, or using breeds adapted to tropical hot dry climates, like the Damara and Dorper. Albeit 15 years in Australia, little is known on how these sheep compare to Australian Merino. Here, the responses of the Damara, Dorper and Merino breeds to nutritional stress were compared. Seventy-two 6-month-old ram lambs, 24 from each breed, were allocated to growth (gaining 100 g/day) or restricted diets (losing 100 g/day, 85 % of maintenance needs). Animals were weighed and carcass and meat characteristics determined. Results point out to the existence of important differences between the three genotypes, in particular between the Merino and the Southern African breeds. Additionally, Merino ram lambs seem to have been more influenced by SWL than the other two, with consequences on meat characteristics. 相似文献
4.
Zarkawi M 《Tropical animal health and production》2011,43(7):1311-1318
Fifty cyclic fat-tailed Syrian Awassi ewes aged 2–4 years, with a mean weight of 51.4 kg, were used for 4 years to assess
the accelerated lambing system (three lambings in 2 years). Ewes were divided into two groups: treated (T) and untreated (C).
Ewes in the T group were treated with flugestone acetate for 14 days and injected intramuscularly at sponge withdrawal with
500 IU of equine chorionic gonadotropin (eCG). Results indicated that ewes in the T group exhibited oestrus and were mated
within 5 days post sponge removal compared to 11 days for ewes in the C group, and the difference in oestrus response between
the two groups was significant (P < 0.001). Repeated hormonal treatments had no significant (P > 0.05) effect on the lamb birth weight. However, significant (P < 0.001) differences in the lamb birth weight were observed between singles and multiple births. In the treated ewes, the
total number of lambs born was 211–157 parturitions, and the multiple birth rate reached 27.4%, whereas the rate in the untreated
group was 6.3% with the difference being significant (P < 0.05). In the untreated ewes, the total number of lambs born was 14–13 parturitions (12 singles and 1 twin). Fecundity
rates were 135.1% and 106.3% in the treated and untreated ewes, respectively, and the difference was significant (P < 0.05). Repeated administration of eCG had no negative effect on fertility of Syrian Awassi ewes. However, anti-eCG antibodies
were produced following eCG injections with extremely high individual differences in the immune response among ewes. 相似文献
5.
Sejian Veerasamy Maurya Vijai Prakash Naqvi Sayeed M. K. 《Tropical animal health and production》2010,42(8):1763-1770
A study was conducted to assess the effect of combined stresses (thermal and nutritional) on physiological adaptability and
growth performance of Malpura ewes. Twenty-eight adult Malpura ewes (average BW 33.56 kg) were used in the present study.
The ewes were divided into four groups, viz., GI (n = 7; control), GII (n = 7; thermal stress), GIII (n = 7; nutritional stress), and GIV (n = 7; combined stress). The animals were stall-fed with a diet consisting of 60% roughage and 40% concentrate. GI and GII
ewes were provided with ad libitum feeding, while GIII and GIV ewes were provided with restricted feed (30% intake of GI ewes)
to induce nutritional stress. GII and GIV ewes were kept in climatic chamber at 40°C and 55% RH for 6 h/day between 1000 and
1600 hours to induce thermal stress. The study was conducted for a period of two estrus cycles. The parameters studied were
feed intake, water intake, physiological responses (viz., respiration rate, pulse rate, and rectal temperature), body weight,
and body condition scoring (BCS) of ewes. Both thermal and combined stress significantly (P < 0.05) affected the feed intake, water intake, respiration rate, and rectal temperature. The feeding schedule followed in
the experiment significantly (P < 0.05) altered the body weight and BCS between the groups. The results reveal that when compared with thermal stress, nutritional
stress had less significant effect on the parameters studied. However, when both these stresses were coupled, it had a significant
influence on all the parameters studied in these ewes. It can be concluded from this study that when two stressors occur simultaneously,
the total cost may have severe impact on biological function. 相似文献
6.
Obeidat BS Awawdeh MS Titi HH AbuGhazaleh AA Al-Lataifeh FA Alawneh IA Abu Ishmais MA Qudsieh RI Subih HS 《Tropical animal health and production》2011,43(6):1211-1217
Twenty nursing Awassi ewes (BW = 50 ± 2.35 kg, age = 4.5 ± 1.2 years) with their lambs were used to evaluate the effects of
feeding calcium salts in lactation diets on performance and pre-weaning growth of their lambs. Treatments were 0% calcium
salts (CON) or 5% calcium salts (FAT). At the end of the study, a digestibility experiment was performed. Milk yield was greater
(P < 0.05) for ewes fed the FAT diet than the CON diet. Milk composition was similar (P > 0.05) between diets. However, milk energy value (kcal/day) tended to be greater (P = 0.07) for the FAT diet than the CON diet. Concentrations of milk C18:1c9 and C20:0 were greater (P < 0.05) in ewes fed the FAT diet than the CON diet. However, concentration of trans-10, cis-12 CLA was lower (P = 0.05) in the FAT diet than in the CON diet. No differences in feed intake and body weight change were detected between
diets. Digestibility of dry matter, organic matter, crude protein, ether extract, neutral detergent fiber, and acid detergent
fiber were similar (P > 0.05) for diets. For lambs, weaning weight was not affected by treatments. However, average daily gain and total gain were
greater (P = 0.053) for the FAT diet than the CON diet. Results suggest that supplementing lactating ewes with calcium salts at the
beginning of lactation phase improves daily milk yield of ewes and pre-weaning growth of their lambs with no major negative
impact on feed intake and digestibility. 相似文献
7.
Yilmaz M Altin T Karaca O Cemal I Bardakcioglu HE Yilmaz O Taskin T 《Tropical animal health and production》2011,43(8):1555-1560
The aim of this study was to determine the effects of the body condition score (BCS) of ewes before and during the mating
season on their reproductive performance under an extensive production system. In this study, 240 Kivircik sheep from the
flocks of two breeders were used for over a 2-year period. The flocks were fed under extensive conditions on natural pastures
throughout the year. The ewes were synchronized in two different periods, one of which was 45 days before the other. Before
the introduction of rams to the ewes, the ewes were weighed after measuring their BCS. Detailed records were kept for every
flock in each year. We found significant effects of BCS on pregnancy rate, lambing rate (P < 0.05) and fecundity (P < 0.05). The BCS for the highest pregnancy, lambing rate, and fecundity was determined between 2.01 and 3.00, while the lowest
rates for these traits were ≤1.50. The highest rates of the pregnancy rate, lambing rate, and fecundity and gestation productivity
were 75.9%, 70.9%, 1.11 and 3.34 kg, respectively. 相似文献
8.
A study was carried out to evaluate the influence of vitamin and trace mineral supplementation on milk production and composition
in grazing dairy ewes during the dry season. Ewes (n = 50) were assigned at weaning to blocks and treatments. Ewes were daily conducted (8 h/day) on a pasture based on Italian
ryegrass (Lolium multiflorum). At fold, ewes received a basal diet composed by ad libitum oat hay and a definite amount of a pelleted concentrate. Dietary
treatments included: (1) the control concentrate containing background of vitamin and trace mineral only, and (2) the experimental
concentrate containing the premix supplement (10 g/kg of dry matter). Vitamin and trace mineral supplementation did not affect
ewes’ body weight. Milk, fat- and protein-corrected milk, fat percentage, and clotting properties were improved in ewes fed
supplemented concentrate. There was a week × treatment interaction (P < 0.05) for yield of milk and corrected milk that was greatest at peak production in ewes fed the premix. Our findings indicate
that in grazing dairy ewe, the dietary vitamin and trace mineral supplementation during dry season led to an increase of milk
production and quality, with positive improvement in milk clotting aptitude. 相似文献
9.
Effects of genetic and environmental factors on pre-weaning and post-weaning growth were studied in West African crossbred
sheep. Effects of lamb genotype (7/8 Sahelian–1/8 Djallonké, 3/4 Sahelian–1/4 Djallonké and 1/2 Sahelian–1/2 Djallonké; hereafter
denoted 7/8Sa, 3/4Sa and 1/2Sa, respectively), parity, type of birth, sex of lamb and year-season of lambing on birth weight,
weaning weight, 8-month weight and pre- and post-weaning growth rates were determined. At birth 7/8Sa and 3/4Sa lambs were
heavier (p<0.01) than 1/2Sa lambs. Lambs born to first-parity ewes were lighter (p<0.01) at birth than lambs of older ewes. At weaning and 8 months of age, lambs born to fourth-parity ewes were heavier (p<0.05) than those born to ewes of the other parities. Parity did not have any significant effects on pre-weaning growth rate.
Lambs born in the rainy season of 2001 were significantly heavier at birth and at 8 months of age than those born in the dry
season of 2001/02, but there was no difference between the two groups at weaning. Pre-weaning growth rate was significantly
faster in lambs born in the dry season of 2001/02 but the reverse was true for post-weaning growth rate. 相似文献
10.
Youssef Mohamed A. El-Khodery Sabry Ahmed El-deeb Wael M. El-Amaiem Waleed E. E. Abou 《Tropical animal health and production》2010,42(8):1771-1777
As little is known about the oxidant/antioxidant status in buffalo with ketosis, the present study was delineated to assess
the oxidative stress level associated with clinical ketosis in water buffalo. A total of 91 parturient buffalo at smallholder
farms were studied (61 suspected to be ketotic and 30 healthy). Clinical and biochemical investigations were carried out for
each buffalo. Based on clinical findings and the level of beta-hydroxybutyrate (BHB), buffalo were allocated into ketotic
(42), sublinical cases (19). Clinically, there was an association between clinical ketosis and anorexia (p < 0.001), constipation (p < 0.001), decreased milk yield (p < 0.001), ruminal stasis (p < 0.001), and loss of body condition (p < 0.01). Biochemically, in clinical ketosis compared with subclinical and control cases, there was a significant increase
(p < 0.05) of BHB, malondialdehyde (MDA), nitric oxide (NO), aspartate aminotransferase (AST), L-alanine aminotransferase (ALT).
However, there was a significant decrease of glucose, phosphorus, magnesium,total cholesterol and HDL-cholesterol. There was
a positive correlation between BHB and MDA (r = 0.433), BHB and NO (r = 0.37), MDA and NO (r = 0.515), and Glucose and phosphorus(r = 0.521). However, there was a negative correlation between BHB and glucose (r = −0.341) and HDL and NO (r = −0.379). The result of the present study indicates that hyperketonemia in buffalo is associated with an increase of oxidative
stress levels. Further studies need to be done on the efficacy of antioxidants as an ancillary treatment to relief the oxidative
stress caused by ketosis. 相似文献
11.
The effect of GnRH administration on superovulatory response of ewes treated with equine chorionic gonadotrophin (eCG) in
breeding and nonbreeding seasons and the contribution of laparoscopic insemination to the improvement of fertilization and
embryo recovery were investigated. Twenty-four nonpregnant Awassi ewes of 3–4 years of age were randomly allocated into two
groups (n = 12). Each ewe was treated with a progesterone impregnated intravaginal sponge for 12 days. The following superovulation
treatment was used: ewes of group 1 received 1,200 IU of eCG once as an intramuscular injection 48 h prior to sponge withdrawal;
ewes of group 2 also received 1,200 IU of eCG once as an intramuscular injection, 48 h prior to sponge withdrawal and after
24 h of sponge removal. Ewes were injected with 80 μg of GnRH. Ewes of groups 1 and 2 were further subdivided into four equal
groups (n = 6). Subgroups A and C (superovulated with eCG and eCG plus GnRH, respectively) were mated naturally at least two times
with Awassi rams of proven fertility at 8-h intervals. Subgroups B and D (same as A and C) had intrauterine insemination at
44–46 h after sponge removal, under laparoscopic visualization of uterine horns, depositing 1 ml of diluted semen containing
100 × 106 motile sperm in the distal portion of each uterine horn. Ovarian response was assessed by determining the number of corpora lutea by laparoscopy at day 6 after mating. Embryo recovery was performed by using a semi-laparoscopic flushing procedure in both
uterine horns. Results of the present study showed that ewes treated in breeding season with eCG plus GnRH has a higher number
(P < 0.05) of corpora lutea than eCG alone as 7.33 ± 0.54 and 4.33 ± 0.39, respectively. There was no significant difference in the number of corpora lutea in nonbreeding season when ewes treated with eCG and eCG plus GnRH. The number of unovulated follicles was significantly
higher (P < 0.05) in eCG treated ewes than in ewes treated with eCG plus GnRH, both in the breeding and nonbreeding seasons. The number
of recovered embryos from ewes treated with eCG plus GnRH and eCG differ significantly (P < 0.05) as 4.32 ± 0.56 and 1.06 ± 0.26, respectively, in the breeding seasons. No significant difference was observed when
these hormones used for superovulation in the nonbreeding season. A higher number of unfertilized ova (P < 0.05) was observed in ewes when naturally inseminated than in ewes inseminated using the intrauterine laparoscopic technique.
Higher rate of embryo recovery (P < 0.05) was achieved when ewes were inseminated via intrauterine (4.66 ± 0.66) compared with ewes naturally mated (2.16 ± 0.74).
The fertilization rate in ewes inseminated intrauterine using laparoscopic techniques and naturally mated were 91.5% and 44.8%,
respectively. Fertilization failure in ewes inseminated intrauterine using laparoscopic techniques and naturally mated were
8.4% and 55.2%, respectively. It could be concluded that administration of GnRH 24 h after sponge removal increased ovulation
rate of Awassi ewes treated with eCG for superovulation in the breeding season. The use of eCG to induce superovulation in
Awassi ewes combined with laparoscopic intrauterine insemination increases the fertilization rate. 相似文献
12.
Hoque MA Skerratt LF Rahman MA Alim MA Grace D Gummow B Rabiul Alam Beg AB Debnath NC 《Tropical animal health and production》2011,43(2):431-440
Duck rearing is an important component of sustainable living in poor rural communities, especially as a source of subsistence.
A study was conducted on 118 households (N = 1,373 Jinding ducks, Anas platyrhynchus) from December 2002 to February 2004 on Hatia Island in Bangladesh with the aim of identifying the factors that limit the
health and production of Jinding ducks. Overall duck mortality was 29.3%, with disease (19.7%) being a more significant factor
than predation (9.6%; p = 0.001). Duck mortality also varied significantly among study zones (p < 0.001). Common diseases were duck plague (21.1%) and duck cholera (32.1%). Helminth infection was prevalent, with endemic
trematode (Prosthogonimus spp., Trichobilharzia spp., Echinostoma spp.) and nematode (Cyathostoma bronchialis, Amidostomum anseris, Heterakis gallinarum, Capillaria spp., and Echinuria spp.) infections and epidemic cestode infections due to Hymenolepsis setigera. The median egg production rate per duck per household was 93 for a 6-month laying period. The odds of diminished egg production
(average ≤ 93 eggs per duck per household for a 6-month laying period) was 25.4 times higher in ducks that were kept in traditional
duck houses (p < 0.001) and 14.2 times higher in ducks that experienced delays in the onset of sexual maturity (days 191 and 280; p < 0.001). Ducks that were provided snails for a shorter period of time over the laying period were 18.2 times more likely
to produce fewer eggs than their longer fed peers (p = 0.002). In conclusion, duck mortalities due to diseases and predation and parasitic infections appear to be common constraints
on household duck production on Hatia Island. Additionally, improving duck housing and providing longer nutritional supplementation
with snails increased the production capabilities of household-raised Jinding ducks on Hatia Island. 相似文献
13.
Effects of supplementation and milking of Matebele does four weeks pre-partum to weaning, on milk yield, kid birth weight
and growth rate were studied. Forty does were divided into four treatments: supplemented and milked (SM), supplemented and
not milked (SNM), not supplemented and milked (NSM); and not supplemented and not milked (NSNM). Supplemented goats were given
200 g/doe/day of Dichrostachys cinerea pods containing 19% CP. The study was carried out in September during time of feed unavailability and animals were grazed
on rangelands for seven hours before being given the supplement. Fifty-six kids were born from all the experimental animals
and 24 were singles whereas 32 were twins. Milk yield was higher (P < 0.05) in supplemented than non-supplemented does. Although supplementation had no effect on kid birth weights, growth rates were
higher (P < 0.05) in the SNM group (103 ± 10.1 g/day) than in the SM group (74 ± 10.8 g/day). Among the non-supplemented groups, kids from
milked does had higher (P < 0.05) daily gains (85 ± 10.9 g/day) than those from non-milked does (67 ± 10.7 g/day). Weaning weights were higher (P < 0.05) in SNM does (12.8 ± 1.30 g/day) than in the SM does (10.2 ± 1.17 g/day). Among kids from the non-supplemented does, those
from milked does had superior (P < 0.05) weaning weights (11.2 ± 1.23 g/day) than those from non - milked does (9.2 ± 1.27 g/day). Mortalities were also lowest in
kids born from SNM does. It is concluded that pre-partum to weaning supplementation generally increases milk production which
then increases kids growth rates and weaning weights, as well as reduce kid mortalities. 相似文献
14.
Gastrointestinal nematode infections in small ruminants under the traditional husbandry system during the dry season in southern Ethiopia 总被引:1,自引:0,他引:1
Rahmeto Abebe Mebrahtu Gebreyohannes Solomon Mekuria Fufa Abunna Alemayehu Regassa 《Tropical animal health and production》2010,42(6):1111-1117
A cross-sectional study was conducted from November 2008 to February 2009 to investigate the prevalence and intensity of infection
and risk factors of gastrointestinal (GI) nematodes in small ruminants kept under the traditional husbandry system in two
districts in southern Ethiopia. Faecal samples collected from a total of 510 small ruminants (284 sheep and 226 goats) and
analysed by a modified McMaster technique revealed that 222 animals (43.5%) were found to be infected with one or more GI
nematodes. Five identical genera of nematodes were found in both sheep and goats, which in order of predominance were Haemonchus (56.3%), Trichostrongylus (39.6%), Oesophagostomum (22.9%), Trichuris (21.6%) and Bunostomum (10.4%). No significant (p > 0.05) differences were observed between sheep and goats proportions except for Trichuris (p < 0.05). In both sheep and goats, most of the animals were heavily infected showing faecal egg counts (FECs) above 1,200 epg.
Sheep had a significantly (p < 0.05) higher mean FEC than goats. In sheep and goats, both the prevalence of GI nematodes and mean FEC were significantly
(p < 0.001) associated with body condition score and faecal consistency but not with district, sex and age (p > 0.05 for each factor). In conclusion, the observation of a strong association of GI nematodes with poor body condition
coupled with heavy intensity of infection in the majority of infected animals and an abundance of nematode genera of widespread
economic and pathological significance warrants the institution of appropriate control measures that should necessarily include
improvement of the nutritional status of the animals. 相似文献
15.
M. Mohan V. Ulaganathan I. M. Rodricks C. K. Bhuvanakumar M. Iyue 《Tropical animal health and production》1986,18(3):171-176
Summary Lambing records from 482 Merino ewes, 533 Nilagiri ewes and 192 halfbred Merino ewes were used to estimate the number of ewes
lambing per ewe inseminated, number of lambs born per ewe lambing, number of lambs weaned per lamb born and number of ewe
lambs reaching joining age per ewe lamb weaned. Adult viability was studied by following through the life of 385 Merino ewes,
192 Nilagiri ewes and 61 halfbred ewes in the breeding flock from one and a half to seven and a half years of age. The genetic
groups differed significantly for all the reproductive traits but not for adult viability. Lower values of number of ewes
lambing per ewe inseminated compared to the number weaned and the number reaching joining age indicate that infertility and
embryonic mortality were the main sources of loss.
Resumen Se utilizaron registros de nacimiento de 482 ovejas Merino, 533 ovejas Nilagiri y 192 ovejas Merino media sangre, para estimar el número de partos por oveja inseminada, número de corderos nacidos por parto, número de corderos destetados por corderos nacidos y número de corderos en edad de monta por cordero destetado. La viabilidad adulta se estudió siguiendo a través del tiempo, 385 ovejas Merino, 192 ovejas Nilagiri y 61 ovejas media sangre. La observación empezó al a?o y medio de vida, y continuó hasta los siete y medio a?os. Todos los grupos genéticos fueron significativamente diferentes en todos los aspectos reproductivos, más no en la viabilidad adulta. Los valores más bajos de número de partos por oveja inseminada, comparados al número destetado y al número de corderos en edad de monta, indican que la infertilidad y mortalidad embrionaria fueron las principales causas de dicha pérdida.
Résumé On a utilisé les données d’agnelage de 482 brebis merinos, 533 Nilagiri et 192 métis mérinos pour estimer le nombre de brebis agnelant par rapport à celles inséminées, le nombre d’agneaux nés par brebis agnelant, le nombre d’agneaux sevrés par rapport aux agneaux nés et le nombre de jeunes brebis atteignant l’age de la lutte par rapport à celles sevrées. La viabilité des adultes a été étudiée en suivant au long de leur vie 385 brebis mérinos, 192 Nilagiri et 61 métis d’un troupeau d’élevage; l’age se répartissant de 1 an et demi à 7 ans et demi. Les groupes génétiques se différencient pour tous les paramètres de production mais non pour la viabilité à l’age adulte. La comparaison des valeurs les plus basses du nombre de brebis agnelant par rapport à celles inséminées, avec le nombre d’agneaux sevrés et le nombre atteignant l’age d’accomplement indique que l’infertilité et la mortalité des embryons sont les principales causes de perte.相似文献
16.
Lopes JE Maia EL Paula NR Teixeira DI Villarroel AB Rondina D Freitas VJ 《Tropical animal health and production》2006,38(7-8):555-561
In order to evaluate embryo production in Morada Nova (white variety) ewes superovulated with porcine follicle-stimulating
hormone, 20 cycling ewes were used as embryo donors and allocated into two groups according to age: group 1 (ewes aged 1–2
years; n = 9) or group 2 (ewes aged 3–4 years; n = 11). Embryo recovery was performed by laparotomy 5–6 days after oestrus. The evaluation of embryos was made under stereomicroscope
according to International Embryo Transfer Society rules. The overall recovery rate was 64.6% (5.0 ± 0.7 structures per ewe)
and 86.3% of the recovered structures were fertilized. Group 1 was superior (p < 0.05) to group 2 according to recovered (6.6 ± 0.9 vs 3.6 ± 0.8) and fertilized structures (5.6 ± 1.1 vs. 3.5 ± 0.7)
per ewe. In conclusion, the ovarian response and the embryo production in Morada Nova (white variety) sheep subjected to a
standard superovulation treatment were considered satisfactory. In addition, the use of multiple ovulation and embryo transfer
in younger ewes (≤ 2 years old) of this sheep breed appears to be an efficient tool to accelerate the preservation of the
Morada Nova (white variety) breed, since younger ewes are as responsive as older ones. 相似文献
17.
David M. Ribeiro Marta S. Madeira Tanya Kilminster Tim Scanlon Chris Oldham Johan Greeff Joo P. B. Freire Miguel P. Mourato Jos A. M. Prates Andr M. Almeida 《Journal of animal physiology and animal nutrition》2019,103(5):1295-1302
Seasonal weight loss (SWL) is a major constraint in extensive animal production systems in the tropics and Mediterranean. The objective of this study was to characterize the amino acid profile of muscle and hepatic tissues of Australian Merino, Damara and Dorper lambs under restricted feeding to evaluate the impact of SWL at the metabolic and physiological levels. SWL induced generalized muscle protein breakdown among restricted groups of all breeds, with varying intensity. Dorper breed mobilized less muscle amino acids when under these conditions, with the Damara having frequent significant differences, namely by having lower amino acid concentrations in the muscle of restricted lambs. Damara lambs showed greater ability to catabolize branched‐chain amino acids in the muscle tissue, which indicates yet another mechanism that provides the Damara with the necessary tools to endure harsh conditions. Overall, the Damara breed mobilized more muscle amino acids than the other breeds, with a better capacity to catabolize branched‐chain amino acids in the muscle, while maintaining muscle structural integrity. 相似文献
18.
Mohebbi-Fani M Mirzaei A Nazifi S Shabbooie Z 《Tropical animal health and production》2012,44(2):259-265
This study assessed the changes of plasma vitamin A, E, and C and the lipid peroxidation status of sheep during breeding and
pregnancy under drought conditions. The study was conducted on 105 cross-bred fat tailed ewes, 3–5 years old with body condition
scores (BCS) of 2.5 to 3.5. The ewes were grazing on medium-to-low quality forages during summer and low quality forages within
the succeeding months and had ad libitum access to a mixture of alfalfa hay (40%) and wheat straw (60%) in the afternoons. From 3 weeks before breeding till 1 month
after the introduction of rams, 300 g of barley grain/head/day was offered to the ewes and then the supplemental grain was
reduced to 100 g/head/day. For better synchronization of estrus cycles in ewes, they were isolated from the rams for at least
2 months and then kept in close proximity of the rams for 1 week before the introduction of the rams to the ewe flock. Then,
whole blood samples were collected on days 1, 7, 21, and 120 after ram introduction. Vitamins A, E, and C were measured in
plasma. Malondialdehyde (MDA) was measured in the hemolysate as a biomarker of lipid peroxidation. Plasma progesterone (P4)
was measured in the samples of day 120 for assessing pregnancy status of the ewes. Vitamins A and C showed continuous and
significant declines (P < 0.05) through days 1 to 120. Vitamin E declined only during the first 21 days of the study and remained almost constant
till day 120. MDA concentration increased significantly at day 21. An elevated concentration of MDA was also detected at day
120. The difference between days 21 and 120 was not significant (P > 0.05). A positive correlation between vitamins E and C was detected at day 120 (r = 0.349, P < 0.01). Age and BCS did not affect the patterns of changes. Assuming that the ewes with P4 concentrations ≥2.5 ng/ml were
pregnant, 95 out of 105 ewes (90.5%) were pregnant at day 120 of the study. Under the conditions of the present study with
medium-to-low quality pastures as the main sources of feed, ewes of various ages and body conditions may suffer from oxidative
stress during breeding and pregnancy. 相似文献
19.
Rubio Ivette Castillo Epigmenio Soto Rodolfo Alarcón Fernando Murcia Clara Galina Carlos S. 《Tropical animal health and production》2010,42(3):539-545
The aim was to study postpartum follicular population dynamics in Brahman cows in the Mexican humid tropics and under different
stocking rates. Lactating adult cows (n = 104) grazed native grammas (Paspalum spp., Axonopus spp.) under two stocking rates: 2.8 (high) or 1.7 (low) cows/ha. Follicle numbers and their size (millimetres) were measured
by ovarian ultrasound scanning. Animals detected in oestrus and inseminated were taken out of the study. Both stocking rates
produced similar (P < 0.05) body condition scores (BCS) and follicular dynamics. The percent of follicles, averaged over stocking rates, of <4 mm
diminished and those of 5–8 mm increased with time, whilst those of >9 mm remained constant; respective values for the previously
mentioned sizes were 60 days postpartum (n = 101), 49%, 56% and 5%; 120 days (n = 70), 28%, 66% and 6%; and 180 days (n = 15), 9%, 79% and 12%. There was a positive correlation between BCS and follicle number for size <4 mm (r = 0.73, P < 0.01), whilst for size 5–8 mm, this was negative (r = −0.51, P < 0.05), for follicles >9 mm, no difference was found (r = −0.08, P > 0.05). It was concluded that stocking rate did not affect follicular population dynamics of Brahman cows, but BCS dictated
the number and categories of follicles present regardless of the stocking rate utilised. 相似文献
20.
Total body water (TBW) in 17 suckling and six lactating llamas was estimated from isotope dilution at three different post natum and lactation stages using both 18O and deuterium oxide (D2O). In total, 69 TBW measurements were undertaken. While TBW in lactating dams, expressed in kilogram, remained stable during
the three measurement periods (91.8 ± 15.0 kg), the body water fraction (TBW expressed in percent of body mass) increased
slightly (P = 0.042) from 62.9% to 65.8%. In contrast, TBW (kilogram) in suckling llamas increased significantly (P < 0.001) with age and decreased slightly when expressed as a percentage of body mass (P = 0.016). Relating TBW to body mass across all animals yielded a highly significant regression equation (TBW in kilogram = 2.633 + 0.623
body mass in kilogram, P < 0.001, n = 69) explaining 99.5% of the variation. The water fraction instead decreased in a curve linear fashion with increasing body
mass (TBW in percent of body mass = 88.23 body mass in kilogram−0.064, P < 0.001, R
2 = 0.460). The present results on TBW can serve as reference values for suckling and lactating llamas, e.g., for the evaluation
of fluid losses during disease. Additionally, the established regression equations can be used to predict TBW from body mass,
providing that the body masses fall inside the range of masses used to derive the equations. 相似文献