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Manuel Nuñez - One of the best experts on this subject based on the ideXlab platform.
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Proteolysis, lipolysis, volatile compounds and sensory characteristics of Hispánico cheeses made using frozen curd from raw and pasteurized Ewe milk.
The Journal of dairy research, 2012Co-Authors: Rocío Alonso, Pilar Gaya, Antonia Picon, Manuel NuñezAbstract:Hispanico cheese, manufactured from a mixture of cow and Ewe milk, is representative of cheese varieties made using milk from more than one animal species in Mediterranean countries. The shortage of Ewe milk production in autumn hinders the uniformity of Hispanico cheese composition throughout the year. To surmount this inconvenience of Ewe milk seasonality, curds made in spring from raw and pasteurized Ewe milk were stored frozen and used four months later for the manufacture of Hispanico cheese. Experimental cheeses were made by mixing fresh curd from pasteurized cow milk with thawed curd from raw or pasteurized Ewe milk, and control cheese from a mixture of pasteurized cow and Ewe milk in the same proportion. Characteristics of experimental and control cheeses throughout a 60-d ripening period were investigated. On the one hand, the experimental cheese containing frozen curd from raw Ewe milk showed the highest counts of staphylococci, Gram-negative bacteria and coliforms, the highest levels of aminopeptidase and esterase activity, and the highest concentrations of free amino acids, free fatty acids, alcohols and esters. On the other, the experimental cheese containing frozen curd from pasteurized Ewe milk had concentrations of free amino acids, free fatty acids and volatile compounds similar to those of control cheese, with the only exception being a higher level of ketones. Flavour intensity reached the highest scores in the experimental cheese containing frozen curd from raw Ewe milk, followed by the experimental cheese containing frozen curd from pasteurized Ewe milk. Flavour quality scores of both experimental cheeses were similar, and lower than those of control cheese.
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Proteolysis, lipolysis, volatile compounds, texture, and flavor of Hispánico cheese made using frozen Ewe milk curds pressed for different times.
Journal of dairy science, 2010Co-Authors: Antonia Picon, Marta Avila, Pilar Gaya, Estrella Fernández-garcía, Ana Rivas-cañedo, Manuel NuñezAbstract:Abstract Hispanico cheese is manufactured in Spain from a mixture of cow and Ewe milk. Production of Ewe milk varies throughout the year, with a peak in spring and a valley in summer and autumn. To overcome this seasonal shortage, curd from spring Ewe milk may be frozen and used for cheese manufacture some months later. In the present work, Ewe milk curds pressed for 15, 60, or 120 min were held at −24°C for 4 mo, thawed, cut to 1-mm pieces, and mixed with fresh cow milk curd for the manufacture of experimental Hispanico cheeses. Control cheese was made from a mixture of pasteurized cow and Ewe milk in the same (80:20) proportion. Cheeses, made in duplicate experiments, were analyzed throughout a 60-d ripening period. No significant differences between cheeses were found for lactic acid bacteria counts, dry matter content, hydrophilic peptides, 47 out of 68 vol.tile compounds, texture, and flavor characteristics. On the other hand, differences of minor practical significance between experimental and control cheeses, unrelated to the use of frozen Ewe milk curd or the pressing time of Ewe milk curd, were found for pH value, aminopeptidase activity, proteolysis, hydrophobic peptides, free amino acids, free fatty acids, and the remaining 21 vol.tile compounds. It may be concluded that the use of frozen Ewe milk curd in the manufacture of Hispanico cheese does not alter its main characteristics.
P R Kenyon - One of the best experts on this subject based on the ideXlab platform.
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quantifying sheep enterprise profitability with varying flock replacement rates lambing rates and breeding strategies in new zealand
Agricultural Systems, 2020Co-Authors: L.j. Farrell, P R Kenyon, Peter R. Tozer, Thiagarajah Ramilan, L. M. CranstonAbstract:Abstract Sheep sales are the major source of income for most New Zealand sheep enterprises. Terminal (meat breed) sires are used to increase lamb growth rates enabling lambs to be sold earlier at higher prices on a per kg basis. Their use in self-replacing flocks is generally constrained by requirements for purebred Ewe lambs from which to choose Ewe replacements. This study used a bio-economic system-dynamics model of a sheep enterprise to investigate use of terminal sires for a Ewe flock with a range of Ewe replacement and lambing rates. Values from New Zealand industry survey data were used to simulate a representative New Zealand North Island East Coast Hill Country sheep enterprise (self-replacing flock of 2182 mature breeding Ewes with a stable flock size on 549 ha of pasture where 60.8% of feed was consumed by sheep). Three Ewe replacement rates (20%, 25%, and 30% per annum), lambing rates (110, 130, and 150%; lambs weaned per Ewe presented for breeding), and breeding strategies (no terminal sires; breeding the maximum possible proportion of mature Ewes with terminal sires; and breeding half of the maximum with terminal sires) were modelled. Income from lamb sales increased with use of terminal sires, due to increased production of lamb livEweight for sale and lambs sold earlier for higher prices, resulting in greater sheep enterprise cash operating surplus (COS). Sheep enterprise COS increases, from no terminal sire use compared with maximum use of terminal sires, ranged from $3/ha to $101/ha. Larger increases in COS occurred with a higher flock lambing rate and lower Ewe replacement rate, which allowed for terminal sire use over a greater proportion of the flock. Up to 65% of the flock could be bred with terminal sires while producing sufficient numbers of purebred Ewe lambs from which to choose replacements. For an average North Island East Coast Hill Country sheep enterprise with a replacement rate of 25% and lambing rate of 130%, sheep enterprise COS increased by $15,021 with maximum use of terminal sires (45% of the mature Ewe flock), compared with use of only maternal sires. Use of terminal sires increased annual sheep energy demand by up to 6% and changed the sheep feed demand profile, with increases in energy demand post-weaning in December mostly compensated for by subsequent reductions in demand following crossbred lamb sales in January.
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Spline fit (knots at breeding, lambing and weaning each year) predictions of daily live weight of Ewes from their weaning (D99) to the weaning of their last lambs (D2623) for the interaction of dam age group and birth rank.
2019Co-Authors: E. J. Pettigrew, P R Kenyon, S T Morris, S J Pain, R. E. Hickson, N. Lopez-villalobos, H T BlairAbstract:M1 = singleton born to a mature Ewe, M2 = twin born to a mature Ewe, L1 = singleton born to a Ewe lamb, and L2 = twin born to a Ewe lamb. Times marked with an x indicate lambing dates each year (Days 692, 1057, 1442, 1790, 2146, and 2507).
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Survival curves of the Ewes based on the interaction of dam age group (mature Ewe or Ewe lambs) and birth ranks (singleton or twin) for the eight years of the experiment, with actual survival, and imposed survival.
2019Co-Authors: E. J. Pettigrew, P R Kenyon, S T Morris, S J Pain, R. E. Hickson, N. Lopez-villalobos, H T BlairAbstract:(A) The actual survival of the Ewes, with no culling, except for welfare grounds. (B) Imposed culling, with culling for production traits, as per commercial farm conditions. M1 = singleton born to a mature Ewe, M2 = twin born to a mature Ewe, L1 = singleton born to a Ewe lamb, and L2 = twin born to a Ewe lamb. Times marked with an x indicate lambing dates each year (Days 692, 1057, 1442, 1790, 2146, and 2507).
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relationships between prenatal Ewe traits milk production and prEweaning performance of twin lambs
Journal of Animal Science, 2016Co-Authors: A S Danso, P C H Morel, P R Kenyon, H T BlairAbstract:There is limited information on factors affecting twin lamb growth before weaning, which limits the options available to farmers to actively manage lamb growth. Data from 2 multiyear experiments involving 402 twin-bearing Romney Ewes were used to evaluate the effects of prenatal Ewe traits (live weight at mating and set stocking and BCS at mating and set stocking) and combined twin lamb birth weight on Ewe milk production and lamb growth from birth to weaning as well as the proportion of variation in twin lamb growth that could be explained by these variables. Additionally, the effect of accumulated Ewe milk yield over a 42-d period (MY; Days 0 to 42) and accumulated milk components (protein, fat, and lactose) on twin lamb growth were investigated. The effects of prenatal variables on MY, birth weight, and combined twin lamb live weight gain from Day 0 to 42 (LWG) were inconsistent across the 2 experiments. In addition, prenatal Ewe traits ( < 0.05) explained less than 30% of the variation in MY and lamb growth from birth to weaning in both experiments. Combined twin lamb birth weight was positively ( < 0.001) correlated with MY ( = 0.34 and = 0.43 in Exp. 1 and 2, respectively). Combined twin lamb LWG was dependent on Ewe MY ( = 0.43 for Exp. 1 and = 0.30 for Exp. 2). Lactose, fat, and milk CP yields explained 47 and 42% of the variation in lamb LWG in Exp. 1 and 2, respectively. Lactose and milk CP yield positively affected ( < 0.05) LWG in Exp. 1 and 2, respectively. Fat yield had a positive relationship with LWG in Exp. 1 and a negative relationship with LWG in Exp. 2. In conclusion, the measured prenatal Ewe traits had a minimal effect on milk yield and twin lamb growth to weaning. Milk yield and composition explained the greatest proportion of variation in LWG. This suggests that farmers should select Ewes with higher milk yields to maximize twin lamb growth to weaning. However, less than 50% of the variation in LWG and weaning live weight was explained by the measured Ewe and lamb parameters. Therefore, further studies are required to determine additional Ewe or lamb variables that control variation in twin lamb growth.
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Ewe lamb diet selection on plantain plantago lanceolata and on a herb and legume mix including plantain chicory cichorium intybus red clover trifolium pratense and white clover trifolium repens
Animal Production Science, 2015Co-Authors: L M Cave, P R Kenyon, S T Morris, N Lopezvillalobos, P D KempAbstract:The objective of Experiment 1 was to examine the diet selection and grazing preference of Ewe lambs for plantain (Plantago lanceolata), chicory (Cichorium intybus), red clover (Trifolium pratense) and white clover (Trifolium repens). This was examined in a herb and legume sward mix containing plantain, chicory, red clover and white clover between seasons under both hard- and lax-grazing. During early spring, the sward predominately comprised plantain (63%) and chicory (21%) and Ewe lambs grazed a greater proportion (P 0.05) in the average number of Ewe lambs grazing each sward of varying weeks since previous grazing. However, Ewe lambs grazed the 3-week-old plantain growth to a lower (P 0.05) among all swards, regardless of weeks since previous grazing. This suggests that the palatability of plantain is not affected by the time since it was last grazed.
Kreg A. Leymaster - One of the best experts on this subject based on the ideXlab platform.
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evaluation of rambouillet polypay and romanov white dorper rambouillet Ewes mated to terminal sires in an extensive rangeland production system lamb production
Journal of Animal Science, 2017Co-Authors: David R. Notter, G S Lewis, Kreg A. Leymaster, Michelle R. Mousel, J.b. TaylorAbstract:: Ewe productivity (i.e., total number or weight of lambs weaned per breeding Ewe) is a key indicator of lamb production efficiency. This study compared various measures of Ewe productivity and Ewe and lamb performance among Ewes of 3 breed types mated to rams of 4 terminal-sire breed types in an extensive rangeland production system. Purebred Rambouillet ( = 212), purebred Polypay ( = 236), and crossbred Romanov-White Dorper × Rambouillet (RW-RA; = 231) Ewes were produced from locally adapted Polypay and Rambouillet Ewes and then annually mated to Columbia, Suffolk, Columbia × Suffolk, or Suffolk × Columbia sires for up to 4 yr, beginning at 1 yr of age. The cumulative number and weight of lambs weaned through 4 yr were greater for RW-RA (5.9 lambs and 153 kg, respectively) and Polypay Ewes (4.9 lambs and 123 kg, respectively) than for Rambouillet Ewes (2.9 lambs and 99 kg, respectively) and also were greater for RW-RA Ewes than for Polypay Ewes (all 0.74), but Suffolk-sired lambs had the heaviest adjusted birth weights ( = 0.01) and Columbia-sired lambs tended to have the lightest adjusted weaning weights ( = 0.12). Combined effects of heterosis and additive breed effects were associated with greater lambing rates in Ewe lambs, larger litters at all ages, and substantially greater number and weight of lambs weaned for Polypay and RW-RA Ewes than for Rambouillet Ewes.
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evaluation of dorset finnsheep romanov texel and montadale breeds of sheep v reproduction of f1 Ewes in spring mating seasons
Journal of Animal Science, 2004Co-Authors: E Casas, Brad A Freking, Kreg A. LeymasterAbstract:Objectives were to estimate effects of sire breed (Dorset, Finnsheep, Romanov, Texel, and Montadale), dam breed (Composite III and northwestern whiteface), mating season (August, October, and December), Ewe age (1, 2, and 3 yr), and their interactions on reproductive traits of F1 Ewes. A total of 1,799 F1 Ewes produced 3,849 litters from 4,804 exposures to Suffolk rams during 35-d mating seasons over 3 yr. Ewes were weighed at breeding. Conception rate and Ewe longevity (present or absent at 42 mo of age) were determined. Number born and litter birth weight were recorded, and number and weight at weaning and 20 wk of age were analyzed separately for dam- and nursery-reared litter mates. Total productivity through 3 yr of age for each Ewe entering the breeding flock was calculated as the sum of 20-wk weights for dam- or nursery-reared lambs. Interactions of sire breed x mating season, sire breed x Ewe age, and mating season x Ewe age were generally significant, whereas interactions of sire breed, mating season, and Ewe age x dam breed were seldom detected. Interactions of sire breed x mating season were often due to changes in rank as well as magnitude, indicating the importance of matching sire breed to a specific mating season. The number born to Dorset-, Texel-, and Montadale-sired Ewes was not affected by dam breed; however, Finnsheep-sired Ewes out of northwestern whiteface dams were more prolific than Finnsheep-sired Ewes out of Composite III dams, and the opposite situation existed for Romanov-sired Ewes. Least squares means of sire breeds (P < 0.001) for total productivity of dam-reared lambs were 98.5, 103.5, 106.9, 124.6, and 154.9 kg/Ewe entering the breeding flock for Texel, Dorset, Montadale, Finnsheep, and Romanov, respectively. Superior reproduction of Romanov-sired Ewes was due to greater conception rate and prolificacy for each mating season and Ewe age, as well as greater Ewe longevity. Total productivity of F1 Ewes by Composite III dams (125.6 kg) was greater (P < 0.001) than for Ewes born to northwestern whiteface dams (109.7 kg), and the effect of mating season increased (P < 0.001) from August to October to December. Litter weight at 20 wk of age of 2- and 3-yr-old Ewes was similar but greater (P < 0.001) than for 1-yr-old Ewes. Experimental results provide comprehensive information about the appropriate use of these breeds in crossbreeding systems to meet specific production-marketing objectives.
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evaluation of dorset finnsheep romanov texel and montadale breeds of sheep i effects of ram breed on productivity of Ewes of two crossbred populations
Journal of Animal Science, 2000Co-Authors: Brad A Freking, Kreg A. Leymaster, L. D. YoungAbstract:: Effects of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds for performance as sires were estimated in the initial phase of a comprehensive evaluation of these breeds as contributors to sheep crossbreeding systems. Objectives were to evaluate the effects of ram breed, Ewe breed, season of mating, and two-way interactions. Rams from the five breeds were single-sire-mated with Ewes from two breed types to produce lambs over a 3-yr period. Ewes were assigned to one of three distinct 35-d mating seasons initiated each year in August, October, and December. A different sample of six rams per breed was used each year across all three seasons, and each ram was penned with Ewes of both breeds. Traits evaluated and number of Ewe records were conception rate and litter weaning weight per Ewe exposed (n = 3,261) and number born, litter birth weight, average birth weight, number weaned, and litter weaning weight per Ewe lambing (n = 2,751). Ram breed and Ewe breed interacted (P < .01) for conception rate and litter weaning weight per Ewe exposed, implicating mating preferences, particularly of Romanov rams. In mixed groups of Ewes exposed to Romanov rams, conception rate was 12.7% lower and litter weight weaned was 8.4 kg lower in the Ewe breed presumably less preferred for mating by the rams. On a per Ewe exposed basis, Romanov-sired litters produced either the largest or the smallest values for litter weaning weight, depending on the breed of Ewe. Effects of ram breed on number born and litter birth weight interacted (P < .05) with season of mating. The largest litters within each ram breed were associated with the October mating season. Montadale and Romanov rams sired larger and heavier litters from August matings than from December matings, whereas the opposite was true for Dorset-sired litters. Texel- and Finnsheep-sired litters were similar in size and weight from August and December matings. Breed of ram differences affected per Ewe lambing productivity measurements (P < .01). Differences between ram breeds for Ewe productivity were noted, with increased number born and improved survival of crossbred progeny to weaning for Romanov-sired litters. These results may have implications for using these ram breeds as sires in different crossbreeding systems. Structured mating systems or the creation of new composite populations involving these breeds could be used to match the resources, environment, and market of specific production situations.
P Creighton - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the effects of Ewe prolificacy potential and stocking rate on herbage production utilization quality and sward morphology in a temperate grazing system
Grass and Forage Science, 2018Co-Authors: E Earle, N Mchugh, T M Boland, P CreightonAbstract:This study investigated the effect of Ewe prolificacy potential (PP; predicted number of lambs born Ewe−1 year−1), stocking rate (SR; Ewes/ha) and their interaction on herbage dry matter (DM) production, utilization, quality and sward morphology within a temperate grass-based lamb production system. The study had a 2 × 3 factorial design, consisting of two Ewe PP as dictated by sire breed (180 medium prolificacy potential (MP—Suffolk crossbred) and 180 high prolificacy potential Ewes (HP—Belclare crossbred)) and three SR: low (LSR; 10 Ewes/ha), medium (MSR; 12 Ewes/ha) and high (HSR: 14 Ewes/ha). Each treatment was managed in a rotational grazing system, with LSR, MSR and HSR treatments grazing to target post-grazing sward heights (PGSH) of 4.55, 4.15 and 3.75 cm respectively. Herbage DM production (above target PGSH) and utilization were highest at the HSR, intermediate at the MSR and lowest at the LSR (p .05). The proportion of leaf in the sward (above target PGSH) was 4% greater in MSR and HSR compared with LSR (p < .05). In conclusion, findings demonstrate the potential to support increased Ewe PP through the selection of Ewe genotypes of a genetically higher PP and lower mature live weight and increased SR within a temperate grass-based lamb production system.
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a survey of management practices and flock performance and their association with flock size and Ewe breed type on irish sheep farms
The Journal of Agricultural Science, 2017Co-Authors: A Bohan, P Creighton, L Shalloo, T M Boland, N MchughAbstract:A detailed survey was undertaken to assess the rate of production and current management practices on Irish sheep farms and quantify their associations with flock size and Ewe breed type. A total of 39 questions relating to the farm production system and farm management practices were devised, including: producer age, location, farm size, livestock numbers and type, in addition to flock management data such as flock breeding policy, lamb finishing strategy, flock health, lambing date, winter housing and feeding practices. A total of 717 sheep producers were surveyed across 45 different discussion groups. The surveyed respondents were sub-divided into four groups depending on flock size (very small, small, medium and large) and into three groups depending on Ewe breed type (maternal, terminal and hill). The average survey respondent was 48 years old, with a flock size of 150 breeding Ewes on a farm size of 58 ha. The average stocking rates were 6·55 and 3·14 Ewes/ha and weaning rates were 1·44 and 1·02 lambs per Ewe joined to the ram for the lowland and hill flocks, respectively. Relative to very small flocks ( 190 Ewes) had higher stocking rates (6·98 v. 5·66 Ewes/ha) and Ewe to ram ratios (40 v. 30), and tended to lamb later in the year. The rate of technology adoption such as faecal egg sampling and pregnancy scanning was greater on larger flocks compared with smaller flocks. Flocks with maternal Ewe breeds had higher scanning and weaning rates, and drafted a greater proportion of lambs off grass compared with flocks with terminal and hill Ewe breeds. Flocks with maternal and terminal Ewe breed types were more likely to winter house Ewes, lamb indoors, test silage quality and have a handling unit compared with flocks with hill-type Ewe breeds. Results from the present study provide a bank of knowledge on current Irish sheep industry performance and show that flock size and Ewe breed type have a significant impact on key flock performance variables.
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measures of lamb production efficiency in a temperate grass based system differing in Ewe prolificacy potential and stocking rate
Journal of Animal Science, 2017Co-Authors: E Earle, T M Boland, N Mchugh, P CreightonAbstract:The objective of this study was to quantify the effects of Ewe prolificacy potential (PP; predicted number of lambs born Ewe yr), as dictated by sire breed type, and stocking rate (SR; Ewes ha) on Ewe production efficiency (kg lamb live weight weaned:kg Ewe live weight mated), lamb growth, lamb carcass output, and dry matter (DM; kg) and energy (UFL; unit of energy kg DM) consumption (in the form of both grazed and conserved herbage, concentrate supplementation, and total) in a temperate grass-based lamb production system. The study was a 2 × 3 factorial design, consisting of 2 differing Ewe prolificacy potentials (medium prolificacy [MP]-Suffolk-sired crossbred Ewes and high prolificacy [HP]-Belclare-sired crossbred Ewes) and 3 stocking rates: low (LSR; 10 Ewes ha), medium (MSR; 12 Ewes ha), and high (HSR: 14 Ewes ha). Each treatment was managed in a 5-paddock rotational system for the duration of the study. The HP treatment weaned more lambs Ewe and ha ( 0.05). Increasing stocking rate increased the number of lambs weaned ha ( < 0.001) and increased lifetime lamb ADG ha ( < 0.001). Lamb carcass output (kg) ha was highest at the HSR, intermediate at the MSR, and lowest at the LSR ( < 0.001). The quantity of DM and UFL consumed Ewe and lamb unit and kg of lamb carcass produced ha increased as stocking rate increased ( < 0.001). In conclusion, results from this study demonstrate HP Ewes to be more efficient in the production of lamb. Increasing stocking rate provides the opportunity to increase lamb carcass output ha; however, achieving this increase in output required additional DM and UFL Ewe and lamb unit above 12 Ewes ha.
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Effect of Ewe prolificacy potential and stocking rate on Ewe and lamb performance in a grass-based lamb production system
Journal of animal science, 2017Co-Authors: E Earle, T M Boland, N Mchugh, P CreightonAbstract:The objective of the present study was to investigate the effect of Ewe prolificacy potential (PP; predicted number of lambs born per Ewe per year) as dictated by sire breed type, stocking rate (SR; Ewes per ha), and their interaction on Ewe and lamb performance in a temperate grass-based lamb production system. The study was a 2 × 3 factorial design, consisting of 2 differing Ewe PP and 3 SR which included 180 medium prolificacy potential (MP- Suffolk-sired crossbred Ewes) and 180 high prolificacy potential Ewes (HP- Belclare-sired crossbred Ewes) allocated to 1 of 3 ( = 60 Ewes) SR: low (LSR; 10 Ewes per ha), medium (MSR; 12 Ewes per ha) or high (HSR: 14 Ewes per ha). Each treatment was managed in a 5-paddock rotational grazing system for the duration of the study. Medium prolificacy Ewes were consistently heavier ( < 0.001) compared to HP Ewes, with HP Ewes having a higher BCS at lambing and 6 wk post-lambing (PL; < 0.05). Low SR Ewes had a higher BW ( < 0.05) and BCS ( < 0.05) at mating, 6 wk PL, and weaning relative to MSR and HSR Ewes which did not differ from each other. Lambs born to MP Ewes were heavier at birth and weaning ( < 0.001) and achieved a higher ADG from birth to weaning ( < 0.05). Ewe PP had no effect on lifetime ADG or d to slaughter (DTS) with HP lambs yielding a higher carcass weight ( < 0.001). Low SR and MSR lambs achieved higher ADG from birth to weaning ( < 0.001) and weaning weight ( < 0.001) relative to HSR lambs and did not differ from each other, while post-weaning and lifetime lamb ADG was highest at the LSR, intermediate at the MSR, and lowest at the HSR ( < 0.001). A Ewe PP by SR interaction existed for DTS, with MP lambs at the LSR reaching slaughter weight earlier ( < 0.01) relative to HP lambs, while at the MSR and HSR, MP and HP lambs did not differ from each other. High PP Ewes produced a higher average born ( < 0.001) and weaned litter size per Ewe ( < 0.01), with live weight weaned per ha ( < 0.001) increasing as Ewe PP and SR increased. Lambing difficulty, Ewe mother ability and lamb viability did not differ by Ewe PP or SR. In conclusion, the lack of interaction between Ewe PP and SR on many key performance measures in this study demonstrates the potential to increase the live weight of lamb weaned per ha through the use of higher Ewe PP and SR levels, with no effect of Ewe PP on lifetime lamb performance even as SR increased, with reductions in lamb performance primarily occurring at the HSR.
L. D. Young - One of the best experts on this subject based on the ideXlab platform.
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evaluation of dorset finnsheep romanov texel and montadale breeds of sheep i effects of ram breed on productivity of Ewes of two crossbred populations
Journal of Animal Science, 2000Co-Authors: Brad A Freking, Kreg A. Leymaster, L. D. YoungAbstract:: Effects of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds for performance as sires were estimated in the initial phase of a comprehensive evaluation of these breeds as contributors to sheep crossbreeding systems. Objectives were to evaluate the effects of ram breed, Ewe breed, season of mating, and two-way interactions. Rams from the five breeds were single-sire-mated with Ewes from two breed types to produce lambs over a 3-yr period. Ewes were assigned to one of three distinct 35-d mating seasons initiated each year in August, October, and December. A different sample of six rams per breed was used each year across all three seasons, and each ram was penned with Ewes of both breeds. Traits evaluated and number of Ewe records were conception rate and litter weaning weight per Ewe exposed (n = 3,261) and number born, litter birth weight, average birth weight, number weaned, and litter weaning weight per Ewe lambing (n = 2,751). Ram breed and Ewe breed interacted (P < .01) for conception rate and litter weaning weight per Ewe exposed, implicating mating preferences, particularly of Romanov rams. In mixed groups of Ewes exposed to Romanov rams, conception rate was 12.7% lower and litter weight weaned was 8.4 kg lower in the Ewe breed presumably less preferred for mating by the rams. On a per Ewe exposed basis, Romanov-sired litters produced either the largest or the smallest values for litter weaning weight, depending on the breed of Ewe. Effects of ram breed on number born and litter birth weight interacted (P < .05) with season of mating. The largest litters within each ram breed were associated with the October mating season. Montadale and Romanov rams sired larger and heavier litters from August matings than from December matings, whereas the opposite was true for Dorset-sired litters. Texel- and Finnsheep-sired litters were similar in size and weight from August and December matings. Breed of ram differences affected per Ewe lambing productivity measurements (P < .01). Differences between ram breeds for Ewe productivity were noted, with increased number born and improved survival of crossbred progeny to weaning for Romanov-sired litters. These results may have implications for using these ram breeds as sires in different crossbreeding systems. Structured mating systems or the creation of new composite populations involving these breeds could be used to match the resources, environment, and market of specific production situations.
