Range Flock Research Articles

Flock use of the range is associated with the use of different components of a multi-tier aviary system in commercial free-range laying hens

ABSTRACT1. The objective of this study was to investigate the association of using a multi-tier aviary system and access to range on flock uniformity in free-range laying hens, and to determine whether the extent of range use or flock uniformity can be predicted from the use of different levels of the aviary system.2. A total of 13,716 Lohmann Brown hens from five commercial free-range flocks housed in identical houses on the same farm were individually weighed at 16 weeks of age and allocated to five replicate areas within each house. Hen movement in the multi-tier aviary system and on the range was individually monitored using radio frequency identification (RFID). All hens had access to the range from 18 to 22 weeks of age and were exposed to the same management conditions.3. Whilst only one flock significantly changed its flock uniformity with time, they differed from each other in uniformity and body weight (P = 0.001).4. Hens spent most of their available time on the lower aviary tier (7.29 ± 0.029 h/hen/day) and on the upper aviary tier (4.29 ± 0.024 h/hen/day) while the least amount of time was spent on the range and in the nest boxes (0.93 ± 0.005 h/hen/day and 1.48 ± 0.007 h, respectively, P = 0.001).5. Range use was negatively correlated (r = −0.30) to the time spent on the upper aviary tier and positively correlated (r = 0.46) to the time spent on the lower aviary tier (P = 0.001). Bivariate analysis revealed that range and upper aviary resp. lower aviary tier usage had a significant curvilinear association.6. In conclusion, the study showed that range use was associated to the time hens spent on the different tiers of the aviary system. Flock uniformity varied between flocks but was not associated with either range and aviary system usage.

672 How much does a ram lose during the breeding season? Assessment of pre- and postbreeding reproductive traits of rams in a range flock in the Pacific Northwest

672 How much does a ram lose during the breeding season? Assessment of pre- and postbreeding reproductive traits of rams in a range flock in the Pacific Northwest

Reproductive performance of rams in three producer range flocks: Evidence of poor sexual behavior in the field

Poor mating behavior increases ram costs and extends the lambing season while decreasing genetic progress. Producers recognize the importance of ram libido; however, time, labor, and facility constraints limit routine evaluation of males for libido. The current experiment determined the incidence of low- and high-sexually performing rams based on the number of lambs sired by each ram in three range flocks. Rams were evaluated for breeding soundness prior to joining with females. Genomic DNA was extracted from blood samples collected from all rams, and approximately one-third of the lambs and their dams. Microsatellite markers were used to determine parentage. Number of lambs expected to be sired by each ram was established by calculating 99% confidence intervals, based on the expectation that each ram would have equal number of lambs. Rams siring more or less lambs than expected were categorized as high or low sexually performing rams, respectively. Paternity was established for >80% of the lambs sampled. Rams which had higher than expected numbers of lambs made up 23–29% of the ram population but sired from 39.4% to 70% of the lamb crop. Low performing rams (23–43% of the ram population) sired from 3.2% to 16.2% of the lamb crop. Since fertility was evaluated prior to mating, differences in ram fecundity may reflect the expression of sexual behavior in a multi-sire range flock setting. Rams are generally selected for breed characteristics and potential influence on flock genetics will be greater for high- than low-sexually performing rams.

Baggs ewes adapt to maternal undernutrition and maintain conceptus growth by maintaining fetal plasma concentrations of amino acids1

Adequate delivery of AA is essential for normal fetal growth and development. Recently, we reported that when ewes from the University of Wyoming flock (farm flock with adequate nutrition) were fed 50% (nutrient-restricted) or 100% (control-fed) of the NRC-recommended nutrient requirements between d 28 and 78 of gestation, fetal weights as well as concentrations of most AA in maternal and fetal blood were substantially reduced in nutrient-restricted vs. control-fed pregnancies. The current study utilized Baggs ewes, which were selected under a markedly different production system (range flock with limited nutrition), to test the hypothesis that adaptation of ewes to nutritional and environmental changes may alter placental efficiency and conceptus nutrient availability in the face of maternal nutrient restriction. Baggs ewes received 50 or 100% of the NRC nutrient requirements between d 28 and 78 of pregnancy. On d 78, maternal uterine arterial and fetal umbilical venous blood samples were obtained, and the ewes were euthanized. Amino acids and their metabolites (ammonia, urea, and polyamines) in plasma were analyzed using enzymatic and HPLC methods. The results showed that maternal plasma concentrations of 9 AA (Asp, Ile, Leu, Lys, Orn, Phe, Thr, Trp, and Val) as well as maternal and fetal plasma concentrations of ammonia and urea were reduced (P < 0.05) in nutrient-restricted compared with control-fed Baggs ewes. However, fetal plasma concentrations of all AA and polyamines did not differ (P = 0.842) between the 2 groups of ewes. Collectively, these findings suggest that Baggs ewes, by adapting to the harsh conditions and limited nutrition under which they were selected, were able to maintain fetal concentrations of AA in the face of a maternal nutrient restriction through augmenting placental efficiency.

Investigations on the Pathogenicity of Erysipelothrix rhusiopathiae in Laying Hens

Erysipelas was diagnosed in 1998 from 34-wk-old laying hens in a free range flock in Germany. Erysipelothrix rhusiopathiae of serotype 1 was cultured from internal organs of the affected birds. This article describes the pathogenicity of the field isolate of E. rhusiopathiae in experimentally infected specific pathogen-free (SPF) laying hens. Three experiments were performed with SPF chickens inoculated at 17, 27, and 37 wk of age by either intramuscular (IM) or oral route. Inoculated birds were observed for 14 days. The highest mortality rates occurred in older birds, with 100% mortality observed in the 37-wk-old birds inoculated IM, 60% mortality reported in the younger 27-wk-old birds, and no mortality in the 17-wk-old age group. In the orally infected 27-wk-old birds, 40% mortality was detected, whereas no mortality was observed in the oldest birds by the same route. The results of the experiments support the contention that older birds are more sensitive to infection than younger birds and that mortality in laying hens is age related and dependent on the route of infection.

What Exactly Are Your Sheep Eating?: Extend the grazing season and reduce supplementation needs of your range flock injust 60 minutes a day

Extend the grazing season and reduce supplementation needs of your range flock in just 60 minutes a day. DOI:10.2458/azu_rangelands_v27i1_royer

Lifetime lamb and wool production of targhee or Finn-Dorset-Targhee ewes managed as farm or range flock: I. Average annual ewe performance.

Lifetime (5 yr) lamb production and wool production from 207 straightbred Targhee (T) and 474 1/4 Finn-1/4 Dorset-1/2 Targhee (FDT) crossbred ewes managed in a range or farm flock system were evaluated for ewe fertility, prolificacy, ewe fleece weight, and total lamb weight weaned per ewe exposed. Data included 2,620 ewe exposures, 2,384 parturitions, 4,638 lambs born, and 3,498 lambs weaned. Ewes were born in 1984 through 1987 and lambed the first time as 2-yr-olds. Expressed as mean annual values, ewe fertility rates were similar (92.2 vs 91.0%, P = .30) for FDT and T ewes. Finn-Dorset-Targhee ewes had higher (P < .001) prolificacy (2.11 vs 1.75), weaned more lambs per ewe exposed (1.41 vs 1.18), produced more total lamb weight weaned per ewe exposed (33.8 vs 29.9 kg), and lambed 2 d earlier than T ewes. Targhee ewes produced more (P < .001) wool (4.5 vs 3.5 kg) than FDT ewes. Range flock ewes had a higher (P < .001) fertility rate (94.5 vs 88.7%), higher number of lambs weaned per ewe exposed (1.38 vs 1.22), and higher total lamb weight weaned per ewe exposed (34.7 vs 29.0 kg) than farm flock ewes. Farm flock ewes had a higher (P < .001) prolificacy (2.00 vs 1.86) and produced more wool (4.2 vs 3.8 kg) than range flock ewes. Targhee ewes had heavier lambs at birth (5.2 vs 4.6 kg; P < .001) and at weaning (25.8 vs 25.4 kg; P < .05). Range flock lambs were heavier (P < .001) at weaning than farm flock lambs (26.2 vs 24.9 kg). Lambs from FDT dams had a higher (P < .01) survival rate than lambs from T dams (75.6 vs 71.4%). Lamb survival from birth to weaning was higher (P < .001) for range flock lambs than for farm flock lambs (76.6 vs 70.4%). Incorporation of Finnsheep and Dorset breeding increased the reproductive performance in both management systems but decreased wool production.

Lifetime lamb and wool production of targhee or Finn-Dorset-Targhee ewes managed as farm or range flock: II. Cumulative lamb and wool production.

Cumulative lifetime (five lamb crops) lamb production and wool production of 681 ewes were evaluated in this study. Lamb production and wool production from each ewe at the end of age 2, 3, 4, 5, and 6 yr were added to the previous year's production and analyzed within age of ewe. If a ewe failed to lamb, died, or was culled, it received a zero for that year and subsequent years. Main effects in the model included ewe breed and management system. Per ewe entering the study, Finn-Dorset-Targhee (FDT) ewes had a higher (P < .01) number of lambs born (7.42 vs 5.70), number of lambs weaned (5.39 vs 4.48), and total lamb weight weaned (131.7 vs 110.5 kg) than did Targhee ewes. Targhee ewes produced more (P < .01) wool (16.1 vs 13.6 kg) than FDT ewes. Range flock ewes had a higher number of lambs born (6.74 vs 6.38; P < .05), number of lambs weaned (5.39 vs 4.48; P < .01), and total lamb weight weaned (135.8 vs 106.5 kg; P < .01) than did farm flock ewes. Farm flock ewes produced more (P < .01) wool (15.2 vs 14.5 kg). A second analysis based on only those ewes retained at the start of each subsequent breeding season showed FDT ewes had a higher (P < .01) number of lambs born (9.96 vs 8.11), number of lambs weaned (7.61 vs 6.57), and total lamb weight weaned (183.8 vs 165.7 kg) after five lamb crops. Targhee ewes produced more (P < .01) wool (22.5 vs 17.6 kg). Farm flock ewes had a higher (P < .10) number of lambs born (9.18 vs 8.89) and produced more (P < .01) wool (21.1 vs 19.0 kg) than range flock ewes. Range flock ewes weaned more (P < .05) lambs (7.27 vs 6.92) and had more (P < .01) total lamb weight weaned (184.3 vs 165.2 kg) than farm flock ewes.

Production of yearling Targhee or Finn-Dorset-Targhee ewes managed as a farm or range flock.

Production data from 681 yearling ewes were evaluated for the effect of ewe breed and management system on fertility, prolificacy, lamb birth weight, lamb survival, lamb weaning weight, ewe fleece weight, and total lamb weight weaned per ewe exposed. Two hundred seven straightbred Targhee (T) and 474 1/4 Finn-1/4 Dorset-1/2 Targhee (FDT) crossbred ewes managed in a range or farm flock system were included in this study. Ewes were born in 1984 through 1987 and lambed the first time as 2-yr-olds. The basic model included main effects of ewe breed and management system. Lamb sex was added to the model for birth and weaning weight analysis. The FDT ewes had higher (P < .05) fertility (95.3 vs 91.3%) and (P < .01) prolificacy (1.93 vs 1.45 lambs) than the T ewes. Targhee ewes had heavier (P < .01) lambs at birth (5.2 vs 4.0 kg) and weaning (26.1 vs 23.4 kg, P < .01) and produced more (P < .01) wool (3.8 vs 3.2 kg). Lamb survival was not different (P > .10) between the breeds or management systems. Although FDT lambs were lighter at weaning, FDT ewes weaned 5.8 kg more (P < .01) total lamb weight per ewe exposed than did the T ewes (34.7 vs 28.9 kg), because FDT weaned more (P < .01) lambs per ewe exposed (1.46 vs 1.09 lambs). Farm flock ewes were more prolific (1.73 vs 1.64 lambs, P < .05) and had heavier lamb birth weight (4.8 vs 4.4 kg, P < .01) than range flock ewes.(ABSTRACT TRUNCATED AT 250 WORDS)

Persistence of the V4 strain of Newcastle disease virus in an open-range flock of chickens.

The V4 strain of Newcastle disease virus was introduced into a small open range flock of bantam chickens, by dosing half the birds directly into the crop. As indicated by rises in titres of haemagglutination inhibition antibody, the virus spread to the uninoculated birds and persisted in the flock for two years, infecting chickens that were introduced by natural brooding and rearing. All new clutches of chicks seroconverted by 80 days of age, and the titres of adult birds showed a concurrent rise, suggesting that the chicks were amplifying the virus. The modes of spread and of persistence of the virus were not determined; although cloacal swabs were taken regularly, only one yielded virus. Antibody titres of the inoculated birds remained above the presumptive protective level of 3 (log2) for over a year, whereas the titres of birds infected by contact were generally less than 3.

The Relationship of Habitat Quality to Group Size in Hall's Babbler (Pomatostomus halli)

A central problem in evolutionary biology concerns the ecological role of operational altruists (Brown 1975a), or helpers (Skutch 1961), as they are known in certain avian communal or cooperative social systems. Critical to the understanding of their role is determination of the factors controlling their numbers in a group. The present study approaches this question by examining some of the proximate factors that influence flock size in a species of bird with a communal social system (sensu Lack 1968, Brown 1975a). We believe that knowledge of proximate factors will help us to understand the ultimate factors that are responsible for the adaptive aspects of operational altruism in such social systems. The adaptive value of helpers has been discussed elsewhere (e.g., Brown 1974). Hall's Babbler (Pomatostomnus halli) was favorable for this study because its flocks are distinct and the members of a flock readily counted. The species occurs in relatively open habitat so the flocks are easy to find and follow at a distance with minimal disturbance to the birds. Babblers of the genus Pomatostomus occur throughout Australia in suitable habitat. The behavioral ecology of P. temporalis has recently been studied by Counsilman (1974) and King (1974). Babblers in the genus Turdoides have been studied by Zahavi (1974), Gaston and Perrins (1974) and Gaston (1976). In P. temporalis, fertilized eggs are produced by a single pair that is aided in various other aspects of the care of the young by helpers (King 1974). The flock consists of the pair plus the helpers. Limited evidence suggests that this is also true in P. halli (Balda and Brown 1977). Using behavior of the babbler flocks to indicate their order of preference for various types of habitat, we found three vegetational indices of home range quality. We used these to test for correlations between home range quality and flock size.

A Study of Lamb Mortality in a Western Range Flock. I. Autopsy Findings on 1051 Lambs

A Study of Lamb Mortality in a Western Range Flock. I. Autopsy Findings on 1051 Lambs

Selection of Range Rambouillet Ewes

Selection of breeding ewes involves the culling of the least desirable ewes up to the point where a more or less constant number is retained in the breeding flock. To be most effective, culling should be done at an age when reliable measures of merit are available, but before many offspring are produced. The proportion of ewes which may be culled depends not only upon age and death losses but also upon the ages and reproductive rates of the ewes retained in the flock. A knowledge of the interrelationships among selection, age and reproduction is essential to the effective planning of a breeding program. The purpose of this study is to present information on the Selection actually practiced, in order to maintain a constant number, in a range flock of Rambouillet ewes over a period of 15 years at the U. S. Sheep Experiment Station, Dubois, Idaho. Data are also presented on the value of some early measures of mutton and wool characters for predicting lifetime merit and how such factors as age and reproduction have influenced the selection of ewes.