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PubMed2006

Effects of breed, gender, exercise and white-coat effect on markers of endothelial function in dogs.

This study examines how systemic biomarkers of endothelial function and nitric oxide metabolism are affected by exercise in dogs. Furthermore, breed variation and white-coat effect have been tested by sampling three different dog breeds both in their home and in a clinical setting. Short-term exercise increased plasma nitrate and nitrite (NOx) and von Willebrand factor (vWf). There was significant difference between Pointers and the small dog breeds Cairn Terriers and Cavalier King Charles Spaniels in the general plasma levels of vWf and asymmetric dimethylarginine (ADMA). NOx and vWf were significantly higher when the sample was taken in the laboratory cf. at home, whereas ADMA and L-arginine were significantly lower. In conclusion, both short-term exercise and white-coat effect influence several plasma markers of endothelial function depending also on the breed and gender of the dogs. These findings should be considered in future studies concerning endothelial function in dogs.

Alaska↗
PubMed2026

Rapid CRISPR-based bovine embryo sexing to streamline genotype-informed cattle breeding.

Cattle in vitro fertilisation and embryo transfer programmes increasingly rely on embryo-level selection to accelerate genetic gain, but current sexing and genotyping workflows can be costly, slow and logistically demanding. This study developed an efficient, low-resource workflow for bovine embryo sexing that combines whole genome amplification (WGA) with recombinase polymerase amplification-CRISPR-Cas12a (RPA-Cas12a). It also assessed whether the same WGA biopsy products could be used for downstream single nucleotide polymorphism (SNP) microarray genotyping. A one-tube RPA-Cas12a assay targeting the bovine Y-chromosome S4 repeat was developed for fluorescence and lateral flow assay (LFA) readouts. Analytical sensitivity was assessed using serially diluted bovine genomic DNA (gDNA), and breed robustness was tested using male and female gDNA from five major beef breeds and Holstein cattle. The workflow was then applied to WGA products from 22 bovine blastocyst biopsies, with sex calls validated against an established real-time PCR melt curve assay and 100K SNP microarray genotyping. The assay detected male bovine gDNA down to 100 pg using both fluorescence and LFA readouts, with no signal from female gDNA. Male-specific detection was consistent across all breeds tested. All WGA-RPA-Cas12a sex calls from blastocyst biopsies were concordant with real-time PCR and SNP microarray sex calls, and WGA biopsy products produced genome-wide SNP call rates above 85%. This workflow provides a practical approach for rapid bovine embryo sex triage and could reduce unnecessary cryopreservation and genotyping while improving the efficiency of genotype-informed cattle breeding programmes.

Bovine embryo↗
PubMed2004

Distribution of Mycobacterium avium subsp. paratuberculosis in organs of naturally infected bull-calves and breeding bulls.

Paratuberculosis, caused by Mycobacterium avium subsp. paratuberculosis, has particular importance in cattle due to the resulting chronic diarrhoea, weight loss, decreased production, infertility and eventual death. While faecal oral route of infection is generally recognised, reports about semen-derived infection are rare. The objective of this work was to assess whether M.a. paratuberculosis may disseminate from the gastrointestinal tract to reproductive organs, and compare this event between naturally infected bull-calves and breeding bulls. Ten bull-calves, aged 6-28 weeks and four breeding bulls were tested by serology, faecal and tissue culture, IS900 PCR and RFLP. In seven bull-calves M.a. paratuberculosis was isolated predominantly from mesenteric lymph nodes (75%); isolates from mucosa of the intestine constituted 25%. In three breeding bulls, M.a. paratuberculosis was isolated both from intestinal mucosa and mesenteric lymph nodes. Head and mediastinal lymph nodes, liver, spleen and semen of bull no. 1 (Holstein-Friesian); testes and epididymis of bull no. 2 (Piemonte); testes, epididymides and seminal vesicle of bull No. 3 (Hereford); and seminal vesicle of bull No. 4 (Simmental) tested positive by culture. Hot-start PCR revealed M.a. paratuberculosis in semen, seminal vesicle and intestinal tissue where culture isolation was difficult. Isolates from bull-calves and breeding bulls were of RFLP types B-C9 and B-C1, respectively. Bull-calves born in infected herd can be sources of infection when later used for natural mating or artificial insemination. Sub-clinically infected bulls release M.a. paratuberculosis into semen, consequently infecting the uterine environment of cows.

Animals↗
PubMed2004

Prepartum plasma estradiol and postpartum cortisol, but not oxytocin, are associated with interindividual and breed differences in the expression of maternal behaviour in sheep.

Consistent, individual differences in the expression of maternal behaviour have been described in several species including the sheep. The neuroendocrine mechanisms underlying the onset of maternal behaviour in the sheep have been described, although the relationship between hormonal events and individual differences in behaviour has yet to be determined. In this study, we examined whether the individual differences in plasma estradiol, progesterone, oxytocin and cortisol concentrations were related to observed individual and breed differences in maternal behaviours in two breeds of sheep (Scottish Blackface and Suffolk) known to differ in maternal behavioural expression. Maternal estradiol concentration increased rapidly before parturition and was higher in Blackface ewes than Suffolk ewes. Plasma progesterone declined before parturition and was higher in Suffolk than Blackface ewes. Prepartum estradiol, but not progesterone, was related to individual differences in maternal grooming of the lamb. Plasma oxytocin did not differ between breeds in late gestation. There was a tendency for oxytocin to be higher in Blackface than Suffolk ewes immediately after birth. However, there were no significant relationships between prepartum or postpartum oxytocin and any maternal behaviours. Plasma cortisol was higher in Blackface than Suffolk ewes in the last days of pregnancy but rose in both breeds over the last 24 h before parturition and did not differ at delivery. Cortisol peripartum was negatively related to individual differences in maternal affiliative behaviours. These data suggest that estradiol, and potentially cortisol, may mediate individual differences in maternal behaviour in sheep.

Animals↗
PubMed1998

Anopheles culicifacies breeding in Sri Lanka and options for control through water management.

This paper assesses the options for control of malaria vectors through different water management practices in a natural stream in Sri Lanka. The association between water level in the stream and breeding of the immature stages of the primary vector Anopheles culicifacies was investigated and the feasibility of using existing irrigation infrastructure to reduce the breeding potential discussed. The most feasible option would be to implement a management routine where water is released periodically from an upstream reservoir to reduce the number of breeding sites downstream. This study indicates that by regulating the water level above 20 cm in the stream throughout the dry season the breeding of A. culicifacies could be significantly reduced. The intervention would have only limited impact on the water lost for agriculture and the management input would be minimal. However, for the intervention to work a high degree of support from the local community is essential and consultation between government departments needed.

Animals↗
PubMed1998

Selective breeding of rats for high and low motor activity in a swim test: toward a new animal model of depression.

Because low motor activity ina swim test has been found to represent "depression-like" behavior in the rat, Sprague-Dawley (SD) albino rats were selectively bred for low motor activity (low struggling time/high floating time) in a swim test, while others were bred for high motor activity (high struggling time/low floating time). Eighty-four male and 42 female SD rats were initially purchased from Charles-River Breeding Laboratories in 1987, their behavior assessed in a 15-min swim test, and selective breeding carried out by mating those male and female rats that showed either low or high levels of motor activity in the test; results from behavioral testing of the first 18 generations produced by this selective breeding process are reported here. Two rat lines have been obtained, Swim Low-Active (SwLo) and Swim High-Active (SwHi) rats, which differ dramatically in swim-test behavior--SwLo rats show little struggling and much floating, while SwHi rats show the reverse. Activity scores of individual SwLo and SwHi rats now show no overlap. Selective breeding has produced bidirectional changes; that is, SwLo rats are considerably less active than randomly bred Sprague-Dawley albino rats, while SwHi rats are considerably more active than randomly bred rats. Measuring activity of SwLo and SwHi rats in other situations--ambulation in the home cage, open-field activity, exploratory activity in a novel, home cage-like situation, and immobility in the Porsolt swim test--revealed that differences are most pronounced when animals respond to acute challenges; under these conditions, SwHi rats show active, assertive behavior, whereas SwLo rats show a distinct absence of this type of response. When SwLo rats from the 8th to the 11th generations were given antidepressant medication [desipramine, (DMI), a tricyclic, or phenelzine, an MAO inhibitor], chronic but not acute administration of both drugs increased swim-test activity of SwLo rats. Buspirone, an anxiolytic, did not increase activity of SwLo rats. Use of animals selectively bred for high and low activity in the swim test may represent a new tool for studying physiological processes relevant to affective disorders and for testing antidepressant drugs/treatments.

Animals↗
PubMed2001

Effects of follicle stimulating hormone (FSH) on follicular development, oocyte retrieval, and in vitro fertilization (IVF) in ewes during breeding season and seasonal anestrus.

Administration of FSH increases the number of developing follicles, and affects oocyte health and cleavage rate. To determine the optimal level of FSH treatment, studies were conducted during the normal breeding season and seasonal anestrus. In Experiment 1, ewes were implanted with SyncroMate-B (SMB; norgestomet) for 14 days during the breeding season. Beginning on day 12 or 13 after SMB implantation, ewes were treated with saline (control; n=10), or treated with FSH for two days (2D; n=9) or three days (3D; n=10). In Experiment 2, conducted during seasonal anestrus, ewes were implanted with SMB for 14 days (n=23) or were not implanted (n=26). The SMB-implanted and nonimplanted ewes were assigned to one of three treatments as in Experiment 1: control (n=13), 2D (n=21) or 3D (n=15). In Experiments 1 and 2, ewes were laparotomized to count the number of follicles < or = 3 mm and > 3 mm and to retrieve oocytes. Healthy oocytes from each treatment were used for IVF. In Experiment 3, ewes (n=6) were implanted twice with SMB for 14 days during seasonal anestrus. Ewes were injected with FSH for 2 days, and the oocytes were collected and fertilized as in Experiments 1 and 2. In Experiment 1, FSH-treatment increased (P < 0.05) the number of follicles > 3 mm, the number of oocytes retrieved from follicles < or = 3 mm and > 3 mm, the proportion of healthy oocytes, and the number of oocytes used for IVF. Oocytes from control and 2D ewes had greater (P < 0.01) cleavage rates than 3D ewes (68% and 71% vs. 42%). In Experiment 2, implanted and nonimplanted ewes had similar (P > 0.05) numbers of follicles, total oocytes, and healthy oocytes; therefore, data were combined. The FSH treatment increased (P < 0.01) the number of follicles > 3 mm, and the number of oocytes recovered from follicles > 3 mm. The recovery rate of oocytes and the percentage of healthy oocytes were similar for control and FSH-treated ewes. The cleavage rate in Experiment 2 ranged from 4 to 16%. In Experiment 3, the cleavage rate for ewes treated twice with SMB was 27% which tended to be greater (P < 0.07) than for the 2D ewes that received one SMB implant in Experiment 2. These data indicate that FSH increased the number of developing follicles and the number of healthy oocytes retrieved from ewes during the breeding season and seasonal anestrus. However, cleavage rates during seasonal anestrus were lower than during the normal breeding season in both FSH-treated and control ewes. Treatment of ewes for 2 days with FSH resulted in a greater cleavage rate than treatment of ewes for 3 days.

Anestrus↗
PubMed1988

Melatonin advances june breeding and fall lambing in range and farm-flock type ewes.

Influence of melatonin on reproductive performance was evaluated by randomly allotting Polypay-type ewes to four treatments: controls in drylot, melatonin-treated ewes in drylot, controls on range, and melatonin-treated ewes on range. An additional group of Targhees and Rambouillets was randomized by breed as control ewes or melatonin-treated ewes to test effect of melatonin in range ewes. All ewes were supplemented with 0.34 kg/head alfalfa-barley (1:1) pellets from 1600 to 1630 h daily, from April 15 to June 30. Ewes maintained on range received no further supplementation, while ewes in drylot received alfalfa pellets for maintenance. Melatonin was fed at 10 mg hd(-1) d(-1) in the pellet to designated ewes in drylot or on range. Three rams were put with each group of ewes on June 1 and rotated among groups at 7-d intervals during the first 30 d of breeding to reduce sire differences. After the first 30 d, ewe groups were combined with all rams. Melatonin induced (P<0.01) an earlier onset of estrus (approximately 17 d) as indicated by earlier lambing dates in Polypay-type, Rambouillet, and Targhee ewes managed on spring range. Melatonin also increased (P<0.01) the number of ewes that conceived during the first 30 d of breeding (June) for both management treatments (drylot and range) and for all breeds.

Journal Article↗
PubMed1999

An ultrasonographic study of luteal function in breeds of sheep with different ovulation rates.

Development and demise of luteal structures were monitored using daily transrectal ultrasonography in 2 breeds of sheep differing in ovulation rates (nonprolific Western white-faced cross-bred, n = 12 and prolific pure-bred Finn sheep, n = 7), during 1 estrous cycle in the mid-breeding season. Jugular blood samples were collected once a day for radioimmunoassay (RIA) of progesterone. The mean diameter of ovulatory follicles was higher in Western white-faced than in Finn ewes (6.4 +/- 0.2 and 5.3 +/- 0.2 mm, respectively; P < 0.001). The mean volume of luteal structures was higher (P < 0.05) in Western white-faced compared with Finn sheep from Days 5 to 15 of the cycle (Day 0 = day of ovulation). This accounted for the higher (P < 0.05) total luteal volumes recorded in Western white-faced ewes on Day 7 and from Days 11 to 15, despite the higher ovulation rate in Finn ewes (2.7 +/- 0.3 and 1.7 +/- 0.2, respectively; P < 0.05). Mean serum progesterone concentrations were higher (P < 0.05) in Western white-faced than in Finn ewes from Days 4 to 14. Daily total luteal volumes were positively correlated with daily serum progesterone concentrations throughout the cycle in Finn sheep (r > or = 0.40, P < 0.02), and during luteal growth and regression (r > 0.60, P < or = 0.00001) but not during mid-cycle in white-faced ewes (r = 0.16; P = 0.22). During the growth of the corpora lutea (CL), luteal tissue volume increased faster (P < 0.05) than serum progesterone concentrations in both breeds of sheep. During luteolysis, the decrease in luteal volumes parallelled that in serum progesterone concentrations in Finn (P = 0.11) but not in Western white-faced ewes, where luteal volumes decreased more slowly (P = 0.02) in relation to progesterone secretion. Increased ovulation rate in prolific Finn ewes resulted in more but smaller CL, and lower serum progesterone levels compared with nonprolific Western white-faced ewes. We conclude that breed-specific mechanisms exist to control the formation of luteal tissue and progesterone secretion in cyclic ewes differing in prolificacy. The mechanisms may involve ovulation of Graafian follicles at different sizes and inhibitory paracrine effects of CL on co-existing CL.

Animals↗
PubMed2003

Developmental estrogenic exposure in zebrafish (Danio rerio): I. Effects on sex ratio and breeding success.

In vivo studies of fishes exposed to xenoestrogens have reported vitellogenin (Vtg) induction, ovatestes, altered sex ratios, and impaired reproductive capacity. The objective of this study was to determine concentration dependent effects of a weak estrogen receptor agonist, 4-nonylphenol (NP) and a potent estrogen receptor agonist, 17alpha-ethinylestradiol (EE) on sex ratios, gonad morphology, Vtg induction and breeding success in zebrafish (Danio rerio). Fish were exposed from 2 to 60 days post-hatch (dph) to NP (10, 30, or 100 microg/l nominal), EE (1, 10, or 100 ng/l nominal), or solvent control (acetone; 0.2% v/v) in a static-renewal system with replacement every 48 h. At 60 dph, 20 fish from each treatment were euthanized for histological examination of gonads and Western blotting for Vtg using pooled heart homogenates. Remaining fish were reared in clean water until adulthood (120 dph) for breeding studies. Due to high mortality in the 100 ng/l EE group, insufficient fish were available for analyses. The percentage of males at 60 dph changed from 45% (9/20) in solvent controls to 0% at 10 ng/l EE and 10% at 100 microg/l NP. A concentration dependent increase in the number of fish with undeveloped gonads at 60 dph was observed in the EE exposure group. Two fish with ovatestes were observed at 100 microg/l NP, while one was observed at 30 microg/l NP. Western blotting showed induction of Vtg at 30 and 100 microg/l NP and 10 ng/l EE. The sex ratios of adults determined at 160 dph revealed no significant departure from 1 male:1 female, suggesting that exposure of zebrafish to estrogenic chemicals during sexual differentiation and early gametogenesis did not irreversibly alter phenotypic sex. The condition factor of adult fish and ovo-somatic index of adult female fish were also unaffected by developmental exposure to NP or EE. Despite this, breeding trials conducted in adult fish from 120 to 160 dph revealed significant reductions in the percent of viable eggs, hatchability, and swim-up success at 10 ng/l EE and 100 microg/l NP. Our results suggest that functional reproductive capacity (breeding success) may be more sensitive than gross morphological endpoints (condition, ovo-somatic index, sex ratio) in adult zebrafish exposed to xenoestrogens during sexual differentiation and early gametogenesis.

Animals↗
PubMed2001

Behavioural characteristics of two dairy breeds of cows selected (Hérens) or not (Brune des Alpes) for fighting and dominance ability.

Two breeds of dairy cattle, one selected for intra-specific fighting and dominance ability (Hérens, H), the other not selected for this behavioural trait (Brune des Alpes, BA), submitted to the same management techniques, were compared with respect to their social behaviour (dominance, agonistic behaviour, social tolerance, social motivation, social distance), fear reactions, ease of handling and physiological correlates.As expected, cows from the H breed were dominant over the BA cows, they were also less fearful either in response to novel objects or in surprise effect tests and had higher social distances at pasture.On the contrary, H cows were less aggressive in undisturbed groups and more tolerant in a food-competition test than BA cows. There were no differences between the two breeds either in aggressive acts in encounters with unfamiliar animals, or in persistence in conflict situations.Furthermore, H cows were less easy to handle in a standardised test, and tended to be less socially motivated than BA cows. Lastly, H cows had higher plasma testosterone levels, and tended to present a lower increase in plasma cortisol level after a surprise effect than BA cows.Thus, the breeders' selection for fighting and dominance ability in H breed appears to have led to several behavioural and hormonal changes.

Journal Article↗
PubMed1998

Limited effects of heavy metal pollution on foraging and breeding success in the curlew (Numenius arquata).

We examined the effect of heavy metal pollution on the foraging success and breeding performance of the curlew (Numenius arquata) along a documented pollution gradient from a point source, and also by comparing foraging and breeding parameters between the polluted site and two non-polluted areas. Prey biomass and abundance, and foraging success did not vary along the pollution gradient, and were no less at the polluted site than in the non-polluted areas. Furthermore, there was no difference in adult weight during incubation between the polluted and non-polluted areas. There were also no differences in measures of breeding success along the pollution gradient, or between areas, which could be attributed to pollution per se. Egg shells from the polluted area had higher concentrations of heavy metals than in the non-polluted areas, and egg shells close to the pollution source were contaminated more than those further from it. However, there was no difference in calcium concentrations of egg shells or egg-shell thickness between areas. We conclude that in this study there were minimal immediate effects of heavy metal pollution on foraging and breeding success in the curlew.

Journal Article↗
PubMed2002

Susceptibility of trypanotolerant West African Dwarf goats and F1 crosses with the susceptible Sahelian breed to experimental Trypanosoma congolense infection and interactions with helminth infections and different levels of diet.

Forty pure West African Dwarf (WAD) goats and 35 of its F1 crosses with the Sahelian breed were used in a multifactorial experimental design to evaluate the effects of an experimental Trypanosoma congolense infection and interactions with natural helminth infections and different levels of diet on health and productivity of these two breeds. Trypanosome infection caused a severe drop in packed cell volume (PCV), but this was not significantly affected by breed. Neither deworming nor diet had any effect on the course of anaemia after trypanosome infection. The mean score of parasitaemia tended to be higher in crossbreeds than in WAD goats although this was not significant (P>0.05). Similarly, the antibody response to trypanosome infection was not significantly different between breeds. Parasitaemia level was significantly influenced by the level of diet with the group under high supplementation having a higher mean parasitaemia score than the group under low supplementation. Weight loss due to trypanosome infection tended to be greater in crossbreeds than in WAD goats (P>0.05). During this study, there was no difference in mean helminth egg output between crossbred and WAD goats. However, between weeks 4 and 10 after trypanosome infection (corresponding to a period of heavy rainfall and highly infective pastures), the mean egg output was higher in the crossbreeds. The immunosuppressive effect of trypanosome infections was revealed by a lower antibody response to Haemonchus contortus in infected animals compared to the uninfected controls. Trypanosome infection tended to increase strongyle egg output. This study did no reveal any superior trypanotolerance of WAD goats compared to crossbreeds.

Animal Feed↗
PubMed1999

The pathology of Psoroptes ovis infestation in cattle with a special emphasis on breed difference.

In cattle, infestations with P. ovis are responsible for a severe dermatitis. The disease is very common in some breeds of beef cattle whereas dairy cattle such as Frisian Holstein are considered as resistant. In order to investigate the factors responsible for this marked breed susceptibility, the immune response to P. ovis under experimental and field conditions has been studied using serology, lymphocyte transformation assay, intradermal tests and passive cutaneous anaphylaxis in susceptible Belgian White and Blue (BWB) and resistant Frisian Holstein (FH) cattle. The results of published studies are reviewed in this paper; original data on specific hypersensitivity reactions to P. ovisare also presented. The use of a sandwich ELISA allowed the detection of specific antibodies as early as 7 days post-infestation and very high titres were observed. There was a clear positive correlation between the antibody titre and the extent of lesions. This antibody response was associated with a marked in vitro lymphocyte proliferation but there was no difference between susceptible and resistant cattle. The passive cutaneous anaphylaxis test revealed the presence of specific Ig E in actively infested animals irrespective of the breed. Specific Ig E were detected fairly late during the course of an experimental infestation with P. ovis. The intradermal injection of P. cuniculi antigenic extract induced an immediate reaction in all animals including the controls; in contrast, a delayed hypersensitivity reaction was observed in infected BWB animals only. It is concluded that immunological as well as non-immunological factors may be responsible for the breed related susceptibility or resistance to P. ovis.

Animals↗
PubMed2003

Evaluation of cryopreserved stallion semen from Tori and Estonian breeds using CASA and flow cytometry.

Methods to evaluate the quality of frozen-thawed stallion semen are still needed, particularly those considering the sperm function. The present study evaluated sperm motility, membrane and acrosome integrity and the capacitation status of frozen-thawed spermatozoa from seven Tori and six Estonian breed stallions by way of computer assisted sperm analysis (CASA), a triple fluorophore stain combination and Merocyanine 540, respectively, the latter ones using flow cytometry. Two ejaculates from each stallion were cryopreserved using the Hannover method in 0.5 ml plastic straws. Two straws per ejaculate per stallion were thawed at 37 degrees C for 30s. Motility was analysed with CASA immediately after thawing, while for flow cytometry spermatozoa were cleansed by 70:40% Percoll discontinuous density gradient separation before analysed for sperm viability, acrosome integrity (stained with SNARF, PI and FITC-PSA) and capacitation status (stained with Merocyanine 540/Yo-Pro-1). Results (as least square means) were as follows: the motility of frozen-thawed semen was 43.4% for Tori stallions and 42.3% for Estonian stallions (P>0.05). After Percoll separation 79.3% of the spermatozoa from Tori stallions had intact acrosomes and 1.7% of them showed early signs of capacitation. The same parameters for Estonian stallions were 84.5 and 2.3%, respectively. There were no statistically significant differences between breeds or ejaculates within breed for any evaluated parameter. We conclude that triple staining and flow cytometry are valuable techniques to evaluate frozen-thawed stallion spermatozoa, and that no differences in quality of frozen semen were registered between Tori and Estonian breed stallions, allowing implementation of this technology in the Estonian horse population.

Acrosome↗
PubMed2001

A short note on DNA lactotypes in the Churra and Manchega sheep breeds.

The structure and genetic diversity of the Spanish dairy breeds, Churra and Manchega, is analyzed by means of DNA lactotypes observed in alpha(s1)-, alpha(s2)-, beta- and kappa-ovine caseins. The inter-racial distribution of the casein genotypes is also analyzed. The two breeds differ quantitatively as well as qualitatively in their lactotypes. The proportions of unique lactotypes in Churra and Manchega reveal a high degree of within breed diversity. Breed genetic diversity is greater in Manchega (1.28) than Churra (1.53). The probability combination test indicates the existence of significant inter-racial differences.

Journal Article↗
PubMed2002

The origin and genetic diversity of Chinese native chicken breeds.

The first 539 bases of mitochondrial DNA D-loop region of six Chinese native chicken breeds (Gallus gallus domesticus) were sequenced and compared to those of the red junglefowl (Gallus gallus), the gray junglefowl (Gallus sonneratii), the green junglefowl (Gallus varius) and Lafayette's junglefowl (Gallus lafayettei) reported in GenBank, and the phylogenetic trees for the chickens were constructed based on the D-loop sequences. The results showed that the four species of the genus Gallus had great differences among each other the G. g. domesticus was closest to the red junglefowl in Thailand and its adjacent regions, suggesting the Chinese domestic fowl probably originatedfrom the red junglefowl in these regions. The two subspecies of Thailand, G. g. gallus and G. g. spadiceus, should belong to one subspecies because of their resemblance. In the case of native breeds, there existed a great difference between the egg breeds and general purpose breeds, which suggested different maternal origins of the two types.

Animals↗
PubMed2002

Effects of scavenging on diet selection and performance of Rhode Island red and Fayoumi breeds of chicken offered a choice of energy and protein feeds.

An experiment was conducted to evaluate the effect of scavenging on diet selection and the comparative performance of Rhode Island Red and Fayoumi breeds of chicken. The breeds were compared under three feeding/management regimes: (1) a choice of ground noug cake and cracked maize, with confinement; (2) a choice of ground noug cake and cracked maize, but being allowed to scavenge for about 6 h; and (3) a commercial layer mash, with confinement. Scavenging did not change the pattern of diet selection. About 90% of the daily intake of both the confined and scavenging birds under choice feeding comprised maize. The efficiency of feed utilization and nutrient intake were also similar in these groups. The Fayoumi were more efficient in terms of feed conversion, although the egg production performance of the two breeds did not vary significantly. Scavenging hens had a significantly lower egg production than the birds under confinement offered a choice of feeds. Scavenging significantly increased the mortality in both breeds. In conclusion, scavenging affected the performance adversely and, despite the provision of a choice of feed providing a source of energy and protein, both the scavenging and confined birds on choice feeding failed to eat sufficient to meet their protein requirements.

Animal Feed↗