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R D Evans - One of the best experts on this subject based on the ideXlab platform.

  • choice of artificial insemination Beef Bulls used to mate with female dairy cattle
    Journal of Dairy Science, 2020
    Co-Authors: D P Berry, S C Ring, Alan J Twomey, R D Evans
    Abstract:

    ABSTRACT Understanding the preferences of dairy cattle producers when selecting Beef Bulls for mating can help inform Beef breeding programs as well as provide default parameters in mating advice systems. The objective of the present study was to characterize the genetic merit of Beef artificial insemination (AI) Bulls used in dairy herds, with particular reference to traits associated with both calving performance and carcass merit. The characteristics of the Beef AI Bulls used were compared with those of the dairy AI Bulls used on the same farms. A total of 2,733,524 AI records from 928,437 females in 5,967 Irish dairy herds were used. Sire predicted transmitting ability (PTA) values and associated reliability values for calving performance and carcass traits based on national genetic evaluations from prior to the insemination were used. Fixed effects models were used to relate both genetic merit and the associated reliability of the dairy and Beef Bulls used on the farm with herd size, the extent of Holstein-Friesian × Jersey crossbreeding adopted by the herd, whether the herd used a technician insemination service or do-it-yourself, and the parity of the female mated. The mean direct calving difficulty PTA of the Beef Bulls used was 1.85 units higher than that of the dairy Bulls but with over 3 times greater variability in the Beef Bulls. This 1.85 units equates biologically to an expectation of 1.85 more dystocia events per 100 dairy cows mated in the Beef × dairy matings. The mean calving difficulty PTA of the dairy AI Bulls used reduced with increasing herd size, whereas the mean calving difficulty PTA of the Beef AI Bulls used increased as herd size increased from 75 cows or fewer to 155 cows; the largest herds (>155 cows) used notably easier-calving Beef Bulls, albeit the calving difficulty PTA of the Beef Bulls was 3.33 units versus 1.67 units for the dairy Bulls used in these herds. Although we found a general tendency for larger herds to use dairy AI Bulls with lower reliability, this trend was not obvious in the Beef AI Bulls used. Irrespective of whether dairy or Beef AI Bulls were considered, herds that operated more extensive Holstein-Friesian × Jersey crossbreeding (i.e., more than 50% crossbred cows) used, on average, easier calving, shorter gestation-length Bulls with lighter expected progeny carcasses of poorer conformation. Mean calving difficulty PTA of dairy Bulls used increased from 1.39 in heifers to 1.79 in first-parity cows and to 1.82 in second-parity cows, remaining relatively constant thereafter. In contrast, the mean calving difficulty PTA of the Beef Bulls used increased consistently with cow parity. Results from the present study demonstrate a clear difference in the mean acceptable genetic merit of Beef AI Bulls relative to dairy AI Bulls but also indicates that these acceptable limits vary by herd characteristics.

  • a breeding index to rank Beef Bulls for use on dairy females to maximize profit
    Journal of Dairy Science, 2019
    Co-Authors: D P Berry, R D Evans, P R Amer, Timothy J Byrne, A R Cromie, F S Hely
    Abstract:

    ABSTRACT The desire to increase profit on dairy farms necessitates consideration of the revenue attainable from the sale of surplus calves for meat production. However, the generation of calves that are expected to excel in efficiency of growth and carcass merit must not be achieved to the detriment of the dairy female and her ability to calve and re-establish pregnancy early postcalving without any compromise in milk production. Given the relatively high heritability of many traits associated with calving performance and carcass merit, and the tendency for many of these traits to be moderately to strongly antagonistic, a breeding index that encompasses both calving performance and meat production could be a useful tool to fill the void in supporting decisions on bull selection. The objective of the present study was to derive a dairy–Beef index (DBI) framework to rank Beef Bulls for use on dairy females with the aim of striking a balance between the efficiency of valuable meat growth in the calf and the subsequent performance of the dam. Traits considered for inclusion in this DBI were (1) direct calving difficulty; (2) direct gestation length; (3) calf mortality; (4) feed intake; (5) carcass merit reflected by carcass weight, conformation, and fat and the ability to achieve minimum standards for each; (6) docility; and (7) whether the calf was polled. Each trait was weighted by its respective economic weight, most of which were derived from the analyses of available phenotypic data, supplemented with some assumptions on costs and prices. The genetic merit for a range of performance metrics of 3,835 artificial insemination Beef Bulls from 14 breeds ranked on this proposed DBI was compared with an index comprising only direct calving difficulty and gestation length (the 2 generally most important characteristics of dairy farmers when selecting Beef Bulls). Within the Angus breed (i.e., the Beef breed most commonly used on dairy females), the correlation between the DBI and the index of genetic merit for direct calving difficulty plus gestation length was 0.74; the mean of the within-breed correlations across all other breeds was 0.87. The ranking of breeds changed considerably when ranked based on the top 20 artificial insemination Bulls excelling in the DBI versus excelling in the index of calving difficulty and gestation length. Dairy breeds ranked highest on the index of calving difficulty and gestation length, whereas the Holstein and Friesian breeds were intermediate on the DBI; the Jersey breed was one of the poorest breeds on DBI, superior only to the Charolais breed. The results clearly demonstrate that superior carcass and growth performance can be achieved with the appropriate selection of Beef Bulls for use on dairy females with only a very modest increase in collateral effect on cow performance (i.e., 2–3% greater dystocia expected and a 6-d-longer gestation length).

  • relationship between body measurements metabolic hormones metabolites and residual feed intake in performancetested pedigree Beef Bulls
    Livestock Science, 2011
    Co-Authors: A K Kelly, R D Evans, M Mcgee, D H Crews, C O Lynch, A R Wylie, David A Kenny
    Abstract:

    Abstract The objective of this study was to examine the relationship between easily measured, potential physiological and physical indicators of feed efficiency including metabolic hormones, metabolites, ultrasonic muscle and fat measures with performance and efficiency traits in performance tested pedigree Beef Bulls (n = 302; initial bodyweight 493 (SD = 64) kg). Animals were offered a high energy concentrate ad libitum plus 1.5 kg fresh weight grass hay daily and individual feed intake was measured for 70 days. Blood samples were collected by coccygeal venipuncture at the start and end of the performance test period and analysed for plasma concentrations of IGF-I, insulin, leptin and various metabolites. Similarly, ultrasonic muscle and fat depths were measured at the start and end of the test period. Residual feed intake (RFI) was computed for each animal as the residuals from a multiple regression model regressing dry matter intake (DMI) on average daily gain (ADG) and mid-test BW0.75 (MWT). Overall ADG, DMI, feed:gain (F:G) and RFI were 1.91 (SD = 0.29), 10.10 (SD = 1.31), 5.37 (SD = 0.84) and 0.00 (SD = 0.78), respectively. Residual feed intake was strongly correlated with DMI (r = 0.67) and moderately correlated with F:G (r = 0.40). Moderate positive correlations ranging from 0.3 to 0.6 were estimated between ultrasonic measures of final fat and muscle depth and their respective gains over the test period with DMI, ADG and RFI. There was no evidence of a strong association between any of the plasma analytes measured and RFI at either sampling times. However, end of test insulin was negatively correlated (r = − 0.14) with RFI. Final IGF-I concentration was negatively associated with DMI (r = − 0.14) and F:G (r = − 0.15). End of test circulating leptin concentration was positively correlated with DMI (r = 0.14) and F:G (r = 0.15). Plasma glucose concentration at the end of test was negatively related to DMI (r = − 0.21) and F:G (r = − 0.21). A positive relationship was observed between end of test plasma urea concentration and DMI (r = 0.30). Overall, the correlation coefficient estimates between the potential blood markers and measures of intake, performance and efficiency were weak and generally not different from zero. This suggests that it is unlikely that measurement of these metabolic indicators, per se, will be useful in the early identification of feed efficient animals.

  • phenotypic and genetic parameters for different measures of feed efficiency in different breeds of irish performance tested Beef Bulls
    Journal of Animal Science, 2010
    Co-Authors: R D Evans, M Mcgee, D H Crews, J J Crowley, D A Kenny, D P Berry
    Abstract:

    No genetic parameters for performance and feed efficiency traits are available for Irish performance-tested Bulls. The objective of this study was to determine the phenotypic and genetic variation for feed intake, BW, ADG, and measures of feed efficiency including feed conversion ratio (FCR), relative growth rate, Kleiber ratio, residual BW gain (RG), and residual feed intake (RFI). Observations were available on up to 2,605 Bulls for each trait from one test station across 24 yr; breeds included in the analyses were Aberdeen Angus (AN), Charolais (CH), Hereford, Limousin (LI), and Simmental. The test period was at least 70 d. Bulls were individually offered concentrates ad libitum, with a restricted forage allowance. Differences in performance and feed efficiency existed among breeds. For example, AN, on average, ate 0.04 kg of DM/d more than CH but had ADG of 0.14 kg/d less over the 70-d test period. Results showed LI and CH were the most efficient breeds when efficiency was defined as FCR or RFI. When animals were partitioned into groups based on high, medium, or low RFI, the low RFI (i.e., most efficient) group were also the more efficient as defined by RG and FCR. The low RFI group had the same ADG as the medium group and a greater ADG (P < 0.01) than the high group (1.67 vs. 1.66 and 1.63 kg/d); yet they ate 0.67 kg of DM/d less (P < 0.001) than the medium RFI group and 1.22 kg of DM/d less (P < 0.001) than the high RFI (i.e., least efficient) group. Genetic parameters for all performance and efficiency measures were estimated across breeds using linear animal mixed models; heritability estimates for feed efficiency traits ranged from 0.28 ± 0.06 (RG) to 0.45 ± 0.06 (RFI). An additional series of analyses included a maternal component in the model; maternal heritability estimates for feed efficiency traits ranged from 0.05 ± 0.03 (RG) to 0.11 ± 0.05 (relative growth rate). Genetic correlations between most of the different feed efficiency measures were strong. Results from this study indicate significant genetic differences in performance and some measures of feed efficiency among performance-tested Beef Bulls.

D P Berry - One of the best experts on this subject based on the ideXlab platform.

  • choice of artificial insemination Beef Bulls used to mate with female dairy cattle
    Journal of Dairy Science, 2020
    Co-Authors: D P Berry, S C Ring, Alan J Twomey, R D Evans
    Abstract:

    ABSTRACT Understanding the preferences of dairy cattle producers when selecting Beef Bulls for mating can help inform Beef breeding programs as well as provide default parameters in mating advice systems. The objective of the present study was to characterize the genetic merit of Beef artificial insemination (AI) Bulls used in dairy herds, with particular reference to traits associated with both calving performance and carcass merit. The characteristics of the Beef AI Bulls used were compared with those of the dairy AI Bulls used on the same farms. A total of 2,733,524 AI records from 928,437 females in 5,967 Irish dairy herds were used. Sire predicted transmitting ability (PTA) values and associated reliability values for calving performance and carcass traits based on national genetic evaluations from prior to the insemination were used. Fixed effects models were used to relate both genetic merit and the associated reliability of the dairy and Beef Bulls used on the farm with herd size, the extent of Holstein-Friesian × Jersey crossbreeding adopted by the herd, whether the herd used a technician insemination service or do-it-yourself, and the parity of the female mated. The mean direct calving difficulty PTA of the Beef Bulls used was 1.85 units higher than that of the dairy Bulls but with over 3 times greater variability in the Beef Bulls. This 1.85 units equates biologically to an expectation of 1.85 more dystocia events per 100 dairy cows mated in the Beef × dairy matings. The mean calving difficulty PTA of the dairy AI Bulls used reduced with increasing herd size, whereas the mean calving difficulty PTA of the Beef AI Bulls used increased as herd size increased from 75 cows or fewer to 155 cows; the largest herds (>155 cows) used notably easier-calving Beef Bulls, albeit the calving difficulty PTA of the Beef Bulls was 3.33 units versus 1.67 units for the dairy Bulls used in these herds. Although we found a general tendency for larger herds to use dairy AI Bulls with lower reliability, this trend was not obvious in the Beef AI Bulls used. Irrespective of whether dairy or Beef AI Bulls were considered, herds that operated more extensive Holstein-Friesian × Jersey crossbreeding (i.e., more than 50% crossbred cows) used, on average, easier calving, shorter gestation-length Bulls with lighter expected progeny carcasses of poorer conformation. Mean calving difficulty PTA of dairy Bulls used increased from 1.39 in heifers to 1.79 in first-parity cows and to 1.82 in second-parity cows, remaining relatively constant thereafter. In contrast, the mean calving difficulty PTA of the Beef Bulls used increased consistently with cow parity. Results from the present study demonstrate a clear difference in the mean acceptable genetic merit of Beef AI Bulls relative to dairy AI Bulls but also indicates that these acceptable limits vary by herd characteristics.

  • a breeding index to rank Beef Bulls for use on dairy females to maximize profit
    Journal of Dairy Science, 2019
    Co-Authors: D P Berry, R D Evans, P R Amer, Timothy J Byrne, A R Cromie, F S Hely
    Abstract:

    ABSTRACT The desire to increase profit on dairy farms necessitates consideration of the revenue attainable from the sale of surplus calves for meat production. However, the generation of calves that are expected to excel in efficiency of growth and carcass merit must not be achieved to the detriment of the dairy female and her ability to calve and re-establish pregnancy early postcalving without any compromise in milk production. Given the relatively high heritability of many traits associated with calving performance and carcass merit, and the tendency for many of these traits to be moderately to strongly antagonistic, a breeding index that encompasses both calving performance and meat production could be a useful tool to fill the void in supporting decisions on bull selection. The objective of the present study was to derive a dairy–Beef index (DBI) framework to rank Beef Bulls for use on dairy females with the aim of striking a balance between the efficiency of valuable meat growth in the calf and the subsequent performance of the dam. Traits considered for inclusion in this DBI were (1) direct calving difficulty; (2) direct gestation length; (3) calf mortality; (4) feed intake; (5) carcass merit reflected by carcass weight, conformation, and fat and the ability to achieve minimum standards for each; (6) docility; and (7) whether the calf was polled. Each trait was weighted by its respective economic weight, most of which were derived from the analyses of available phenotypic data, supplemented with some assumptions on costs and prices. The genetic merit for a range of performance metrics of 3,835 artificial insemination Beef Bulls from 14 breeds ranked on this proposed DBI was compared with an index comprising only direct calving difficulty and gestation length (the 2 generally most important characteristics of dairy farmers when selecting Beef Bulls). Within the Angus breed (i.e., the Beef breed most commonly used on dairy females), the correlation between the DBI and the index of genetic merit for direct calving difficulty plus gestation length was 0.74; the mean of the within-breed correlations across all other breeds was 0.87. The ranking of breeds changed considerably when ranked based on the top 20 artificial insemination Bulls excelling in the DBI versus excelling in the index of calving difficulty and gestation length. Dairy breeds ranked highest on the index of calving difficulty and gestation length, whereas the Holstein and Friesian breeds were intermediate on the DBI; the Jersey breed was one of the poorest breeds on DBI, superior only to the Charolais breed. The results clearly demonstrate that superior carcass and growth performance can be achieved with the appropriate selection of Beef Bulls for use on dairy females with only a very modest increase in collateral effect on cow performance (i.e., 2–3% greater dystocia expected and a 6-d-longer gestation length).

  • phenotypic and genetic parameters for different measures of feed efficiency in different breeds of irish performance tested Beef Bulls
    Journal of Animal Science, 2010
    Co-Authors: R D Evans, M Mcgee, D H Crews, J J Crowley, D A Kenny, D P Berry
    Abstract:

    No genetic parameters for performance and feed efficiency traits are available for Irish performance-tested Bulls. The objective of this study was to determine the phenotypic and genetic variation for feed intake, BW, ADG, and measures of feed efficiency including feed conversion ratio (FCR), relative growth rate, Kleiber ratio, residual BW gain (RG), and residual feed intake (RFI). Observations were available on up to 2,605 Bulls for each trait from one test station across 24 yr; breeds included in the analyses were Aberdeen Angus (AN), Charolais (CH), Hereford, Limousin (LI), and Simmental. The test period was at least 70 d. Bulls were individually offered concentrates ad libitum, with a restricted forage allowance. Differences in performance and feed efficiency existed among breeds. For example, AN, on average, ate 0.04 kg of DM/d more than CH but had ADG of 0.14 kg/d less over the 70-d test period. Results showed LI and CH were the most efficient breeds when efficiency was defined as FCR or RFI. When animals were partitioned into groups based on high, medium, or low RFI, the low RFI (i.e., most efficient) group were also the more efficient as defined by RG and FCR. The low RFI group had the same ADG as the medium group and a greater ADG (P < 0.01) than the high group (1.67 vs. 1.66 and 1.63 kg/d); yet they ate 0.67 kg of DM/d less (P < 0.001) than the medium RFI group and 1.22 kg of DM/d less (P < 0.001) than the high RFI (i.e., least efficient) group. Genetic parameters for all performance and efficiency measures were estimated across breeds using linear animal mixed models; heritability estimates for feed efficiency traits ranged from 0.28 ± 0.06 (RG) to 0.45 ± 0.06 (RFI). An additional series of analyses included a maternal component in the model; maternal heritability estimates for feed efficiency traits ranged from 0.05 ± 0.03 (RG) to 0.11 ± 0.05 (relative growth rate). Genetic correlations between most of the different feed efficiency measures were strong. Results from this study indicate significant genetic differences in performance and some measures of feed efficiency among performance-tested Beef Bulls.

R R Panting - One of the best experts on this subject based on the ideXlab platform.

  • survey of quality defects in market Beef and dairy cows and Bulls sold through livestock auction markets in the western united states i incidence rates
    Journal of Animal Science, 2011
    Co-Authors: Jason K. Ahola, H A Foster, D L Vanoverbeke, K S Jensen, R L Wilson, J B Glaze, T E Fife, C W Gray, S A Nash, R R Panting
    Abstract:

    ABSTRACT: A survey was conducted to quantify incidence of Beef Quality Assurance (BQA)-related de-fects in market Beef and dairy cows and Bulls selling at auction during 2 seasons in 2008. Twenty-three BQA-related traits were evaluated by 9 trained personnel during sales at 10 livestock auction markets in Idaho (n = 5; Beef and dairy), California, (n = 4; dairy only), and Utah (n = 1; Beef and dairy). Overall, 18,949 unique lots (8,213 Beef cows, 1,036 Beef Bulls, 9,177 dairy cows, and 523 dairy Bulls,) consisting of 23,479 animals (9,299 Beef cows, 1,091 Beef Bulls, 12,429 dairy cows, and 660 dairy Bulls) were evaluated during 125 sales (64 spring, 61 fall) for dairy and 79 sales (40 spring, 39 fall) for Beef. The majority of market Beef cows and Bulls (60.9 and 71.3%, respectively) were predominantly black-hid-ed, and the Holstein hide pattern was observed in 95.4 and 93.6% of market dairy cows and Bulls, respective-ly. Market cattle weighed 548 ± 103.6 kg (Beef cows), 751 ± 176.1 kg (Beef Bulls), 658 ± 129.7 kg (dairy cows), and 731 ± 150.8 kg (dairy Bulls). Most Beef cows (79.6%) weighed 455 to 726 kg, and most Beef Bulls (73.8%) weighed 545 to 954 kg, respectively. Among market Beef cattle, 16.0% of cows and 14.5% of Bulls weighed less than 455 and 545 kg, respectively, and 63.7% of dairy cows and 81.5% of dairy Bulls weighed 545 to 817 kg or 545 to 954 kg, respectively. However, 19.5% of dairy cows and 13.1% of dairy Bulls weighed less than 545 kg. Mean BCS for Beef cattle (9-point scale) was 4.7 ± 1.2 (cows) and 5.3 ± 0.9 (Bulls), and for dairy cattle (5-point scale) was 2.6 ± 0.8 (cows) and 2.9 ± 0.6 (Bulls). Some 16.5% of Beef cows and 4.1% of Beef Bulls had a BCS of 1 to 3, whereas 34.8% of dairy cows and 10.4% of dairy Bulls had a BCS of 2 or less. Emaciation (Beef BCS = 1, dairy BCS = 1.0) or near-emaciation (Beef BCS = 2, dairy BCS = 1.5) was observed in 13.3% of dairy cows and 3.9% of Beef cows. Among Beef cattle, 15.1% of cows and 15.4% of Bulls were considered lame. In contrast, 44.7% of dairy cows and 26.1% of dairy Bulls were lame. Ocular neoplasia (cancer eye) was observed in only 0.6% of Beef cows, 0.3% of Beef Bulls, 0.3% of dairy cows, and 0.0% of dairy Bulls. However, among animals with ocular neo-plasia, it was cancerous in 34.4% of Beef Bulls, 48.0% of dairy cows, and 73.3% of Beef cows. In conclusion, nu-merous quality defects are present in market Beef and dairy cattle selling at auction in the Western United States, which could influence their value at auction.

  • quality defects in market Beef and dairy cows and Bulls sold through livestock auction markets in the western united states ii relative effects on selling price
    Journal of Animal Science, 2011
    Co-Authors: J K Ahola, H A Foster, D L Vanoverbeke, K S Jensen, R L Wilson, T E Fife, C W Gray, S A Nash, Jr Jb Glaze, R R Panting
    Abstract:

    Relative effects of Beef Quality Assurance (BQA)-related defects in market Beef and dairy cows and Bulls on selling price at auction was evaluated during 2008. The presence and severity of 23 BQA-related traits were determined during sales in Idaho, California, and Utah. Overall, 18,949 unique lots consisting of 23,479 animals were assessed during 125 dairy sales and 79 Beef sales. Mean sale price ± SD (per 45.5 kg) for market Beef cows, Beef Bulls, dairy cows, and dairy Bulls was $45.15 ± 9.42, $56.30 ± 9.21, $42.23 ± 12.26, and $55.10 ± 9.07, respectively. When combined, all recorded traits explained 36% of the variation in selling price in Beef cows, 35% in Beef Bulls, 61% in dairy cows, and 56% in dairy Bulls. Premiums and discounts were determined in comparison with a "par" or "base" animal. Compared with a base BCS 5 Beef cow (on a 9-point Beef scale), BCS 1 to 4 cows were discounted (P < 0.0001), whereas premiums (P < 0.05) were estimated for BCS 6 to 8. Compared with a base BCS 3.0 dairy cow (on a 5-point dairy scale), more body condition resulted in a premium (P ≤ 0.001), whereas a less-than-desirable BCS of 2.0 or 2.5 was discounted (P < 0.0001). Emaciated or near-emaciated cows (Beef BCS 1 or 2; dairy BCS 1.0 or 1.5) were discounted (P < 0.0001). Compared with base cows weighing 545 to 635 kg, lighter BW Beef cows were discounted (P < 0.0001), whereas heavier Beef cows received (P < 0.05) a premium. Compared with a base dairy cow weighing 636 to 727 kg, lighter BW cows were discounted (P < 0.0001), whereas heavier cows (727 to 909 kg) received a premium (P < 0.01). Beef and dairy cows with any evidence of lameness were discounted (P < 0.0001). Presence of ocular neoplasia in the precancerous stage discounted (P = 0.05) Beef cows and discounted (P < 0.01) dairy cows, whereas at the cancerous stage, it discounted (P < 0.0001) all cows. Hide color influenced (P < 0.0001) selling price in Beef cattle but had no effect (P = 0.17) in dairy cows. Animals that were visibly sick were discounted (P < 0.0001). Results suggest that improving BCS and BW, which producers can do at the farm or ranch level, positively affects sale price. Furthermore, animals that are visibly sick or have a defect associated with a possible antibiotic risk will be discounted. Ultimately, animals with minor quality defects should be sold in a timely manner before the defect advances and the discount increases.

S P Miller - One of the best experts on this subject based on the ideXlab platform.

  • relationships of nutritional plane and feed efficiency with sexual development and fertility related measures in young Beef Bulls
    Animal Reproduction Science, 2018
    Co-Authors: Stephanie L Bourgon, S P Miller, Diel M De Amorim, T Chenier, M Sargolzaei, Janel E Martell, Yuri R Montanholi
    Abstract:

    Abstract Sexual development in Beef Bulls appears to be influenced by nutritional plane and feed efficiency. Yearling Bulls fed high (GRAIN = 49) and moderate (ROUGHAGE = 109) nutritional planes, were submitted to a performance test where scrotal circumference (SC), scrotum and testis ultrasonograms and hormones were monitored throughout. Scrotal thermographs, blood cell counts and semen were evaluated at the end of the test. Residual feed intake (RFI) was the measure of feed efficiency, and Bulls within each population were characterized as efficient and inefficient. During the test period, the GRAIN group had greater triiodothyronine (T3), leptin and scrotal skin thickness (SST) while having greater T3, leptin, % motile sperm, % normal sperm, scrotal temperature and values for red blood cell variables at the end of the test when compared to the ROUGHAGE group. During the test, the efficient GRAIN group had lesser testis pixel intensity while at the end of the performance test the Bulls of this group had greater % normal sperm and lower testis pixel intensity compared to Bulls in inefficient GRAIN group. In comparison, the efficient ROUGHAGE group had less T3, SC and SST while at the end of the test these Bulls had less T3, leptin, SC, SST and scrotal temperature compared to Bulls in the inefficient ROUGHAGE group. Complete blood cell variables, semen quality, scrotal biometry and thermography explained most of the variation in RFI. Results of the present study support the hypothesis that there is an antagonistic relationship between feed efficiency and sexual development in young Bulls, which seems partially offset when there is a greater plane of nutrition. Thus, feed efficiency should be factored in the reproductive evaluation of sires.

  • associations of blood parameters with age feed efficiency and sampling routine in young Beef Bulls
    Livestock Science, 2017
    Co-Authors: Stephanie L Bourgon, S P Miller, Diel M De Amorim, Yuri R Montanholi
    Abstract:

    Abstract Utilization of blood parameters as proxies for feed efficiency is an avenue to maximize profitability of the Beef industry. Among other factors, age and sampling routine may impact the reliability of potential proxies for residual feed intake (RFI). Thus, the objectives were to assess associations of blood parameters with age and RFI under two sampling routines. Thirty-two crossbred Bulls with an average body weight (BW) of 633±93 kg and 369±29 days of age were studied. Residual feed intake was calculated using average daily gain, BW and ultrasound traits for body composition. Seven blood samples for each bull were collected during a 33-day on-station sampling period and an additional sample was collected at slaughter for analysis of blood metabolites and hormones. Bulls were classified as younger (342±17 days of age) and older (395±4 days of age) and into efficient (−0.55±0.70 kg DM/day) and inefficient (RFI=0.55±0.29 kg DM/day). Means of blood parameters were compared between age and feed efficiency groups using a mixed model for on-station sampling and a general linear model for slaughter sampling. During the on-station sampling, glucose ( P =0.01), potassium ( P =0.01) and insulin-like growth factor 1 ( P =0.01) were lesser in older Bulls while urea ( P =0.05), acetate ( P =0.01), osmolality ( P =0.01), testosterone ( P =0.01) and follicle stimulating hormone (FSH; P =0.04) were greater in older Bulls. At slaughter, carbon dioxide ( P =0.01), brain-derived neurotrophic factor ( P =0.05) and FSH ( P =0.01) were greater in older Bulls. Over the on-station sampling, osmolality ( P =0.05) was greater in inefficient Bulls while leptin ( P =0.01) was greater in efficient Bulls. On the day of slaughter, cholesterol ( P =0.04) and alkaline phosphatase ( P =0.04) were lesser in efficient Bulls. Age and RFI classes interaction was observed for T 3 ( P =0.01) during the on-station sampling where lesser T 3 blood levels where observed in efficient Bulls within the younger group ( P =0.01) and in older Bulls within the inefficient group ( P =0.05). Overall, these results support the association of blood parameters with variation in age and RFI and illustrate the impact of sampling routine on components of intermediary metabolism in yearling Bulls, providing information to the development of proxies for RFI.

  • associations between feed efficiency sexual maturity and fertility related measures in young Beef Bulls
    Animal, 2016
    Co-Authors: A B P Fontoura, Diel M De Amorim, T Chenier, Yuri R Montanholi, Robert A Foster, S P Miller
    Abstract:

    The Beef industry has emphasized the improvement of feed utilization, as measured by modeling feed intake through performance traits to calculate residual feed intake (RFI). Evidence supports an inverse relationship between feed efficiency and reproductive function. The objective of this study was to determine the relationship of reproductive assessments and RFI unadjusted (RFI(Koch)) or adjusted for body composition (RFI(us)) and the relationship among fertility-related parameters. In total, 34 crossbred Bulls were housed together for 112 days of performance evaluation, followed by assessment of scrotum IR imaging, scrotal circumference, testes ultrasonography and semen quality parameters at 377±33.4 days of age. Bulls were slaughtered at 389±34.0 days of age, and analyses of carcass composition, biometrics and histomorphometry of the testis and epididymis were conducted. Bulls were grouped into two subpopulations based on divergence of RFI, and within each RFI model either by including 50% of the population (Halves, high and low RFI, n=17) or 20.6% extremes of the population (Tails, high and low RFI, n=7). The means of productive performance and fertility-related measures were compared through these categories. Pearson's correlation was calculated among fertility-related measures. In the Halves subpopulation of the RFI(us), sperm of low-RFI Bulls had decreased progressive motility (47.30% v. 59.90%) and higher abundance of tail abnormalities (4.30% v. 1.80%) than that of high-RFI Bulls. In the Tails subpopulation of the RFI(Koch), low RFI displayed less variation in the scrotum surface temperature (0.62°C v. 1.16°C), decreased testis echogenicity (175.50 v 198.00 pixels) and larger (60.90 v. 56.80 mm(2)) but less-developed seminiferous tubules than high-RFI Bulls. The evaluation of fertility-related parameters indicated that a higher percentage of immature seminiferous tubules was correlated with occurrence of sperm with distal droplets (r=0.59), a larger temperature variation at the top of the scrotum was correlated with improved sperm progressive motility (r=0.38), a lower occurrence of sperm loose head abnormalities was correlated with larger temperature variation at the lower part of the scrotum (r=-0.43), and a lower minimum testis echogenicity (r=-0.59) and smaller scrotal circumference (r=0.72) were correlated with age. The adjustment for body composition (RFI determination) enabled distinct biological inferences about reproduction and feed efficiency when compared with the non-adjusted model. However, both RFI models and the correlation analysis supported the hypothesis that feed-efficient Bulls have features of delayed sexual maturity. Overall, the assessment of fertility-related measurements is important to avoid the improvement of feed efficiency at the expense of reproductive function in young Bulls.

  • use of live ultrasound weight and linear measurements to predict carcass composition of young Beef Bulls
    Canadian Journal of Animal Science, 2005
    Co-Authors: R Bergen, S P Miller, I B Mandell, W M Robertson
    Abstract:

    Pre-slaughter ultrasound and whole side dissection data from 47 crossbred Bulls were used to assess (1) the relative value of six previously published equations based on live animal measurements, (2) the value of alternative pre-slaughter measurements, and (3) the value of alternative ultrasound probes as predictors of whole side lean meat yield. Analysis of absolute bias-corrected residuals indicated that all six previously published equations predicted whole side lean meat yield with similar accuracy (P = 0.62), but analysis of absolute rank residuals indicated that an equation originally based on carcass measurements tended (P = 0.17) to rank Bulls less precisely than five ultrasound-based equations. Breed composition, age, liveweight, hip width, heart girth, and round muscle depths did not contribute to new lean meat yield prediction equations (P > 0.10), but height, 12th/13th rib body wall, rump fat, and gluteus medius muscle depths and marbling score did (P < 0.10). However, examination of absolute ...

  • genetic parameters and breed differences for feed efficiency growth and body composition traits of young Beef Bulls
    Canadian Journal of Animal Science, 2004
    Co-Authors: F S Schenkel, S P Miller, J W Wilton
    Abstract:

    Genetic associations between feed efficiency, growth, and live ultrasound measured body composition traits were studied in purebred Beef Bulls of six breeds in Ontario bull test stations from 1991 to 2000. Feed traits included average daily feed intake (FI), feed conversion ratio (FCR), and residual feed intake [feed intake adjusted for production alone (RFIp) or production and backfat thickness (RFIb)]. Growth traits were average daily weight gain (ADG), mid-test metabolic weight (MW), hip height (HH), and scrotal circumference (SC). Body composition traits included ultrasound backfat thickness (BF), longissimus muscle area (LMA), and predicted percentage of intramuscular fat (IFAT). Bulls were measured every 28 d for weight and individual feed intake, and at the end of test for ultrasound body composition traits. Number of records per trait ranged from 2284 (FI) to 13 319 (ADG). Fixed effects of test group, breed and end of test age (within breed), and random effects of animal and herd of origin were mo...

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  • survey of quality defects in market Beef and dairy cows and Bulls sold through livestock auction markets in the western united states i incidence rates
    Journal of Animal Science, 2011
    Co-Authors: Jason K. Ahola, H A Foster, D L Vanoverbeke, K S Jensen, R L Wilson, J B Glaze, T E Fife, C W Gray, S A Nash, R R Panting
    Abstract:

    ABSTRACT: A survey was conducted to quantify incidence of Beef Quality Assurance (BQA)-related de-fects in market Beef and dairy cows and Bulls selling at auction during 2 seasons in 2008. Twenty-three BQA-related traits were evaluated by 9 trained personnel during sales at 10 livestock auction markets in Idaho (n = 5; Beef and dairy), California, (n = 4; dairy only), and Utah (n = 1; Beef and dairy). Overall, 18,949 unique lots (8,213 Beef cows, 1,036 Beef Bulls, 9,177 dairy cows, and 523 dairy Bulls,) consisting of 23,479 animals (9,299 Beef cows, 1,091 Beef Bulls, 12,429 dairy cows, and 660 dairy Bulls) were evaluated during 125 sales (64 spring, 61 fall) for dairy and 79 sales (40 spring, 39 fall) for Beef. The majority of market Beef cows and Bulls (60.9 and 71.3%, respectively) were predominantly black-hid-ed, and the Holstein hide pattern was observed in 95.4 and 93.6% of market dairy cows and Bulls, respective-ly. Market cattle weighed 548 ± 103.6 kg (Beef cows), 751 ± 176.1 kg (Beef Bulls), 658 ± 129.7 kg (dairy cows), and 731 ± 150.8 kg (dairy Bulls). Most Beef cows (79.6%) weighed 455 to 726 kg, and most Beef Bulls (73.8%) weighed 545 to 954 kg, respectively. Among market Beef cattle, 16.0% of cows and 14.5% of Bulls weighed less than 455 and 545 kg, respectively, and 63.7% of dairy cows and 81.5% of dairy Bulls weighed 545 to 817 kg or 545 to 954 kg, respectively. However, 19.5% of dairy cows and 13.1% of dairy Bulls weighed less than 545 kg. Mean BCS for Beef cattle (9-point scale) was 4.7 ± 1.2 (cows) and 5.3 ± 0.9 (Bulls), and for dairy cattle (5-point scale) was 2.6 ± 0.8 (cows) and 2.9 ± 0.6 (Bulls). Some 16.5% of Beef cows and 4.1% of Beef Bulls had a BCS of 1 to 3, whereas 34.8% of dairy cows and 10.4% of dairy Bulls had a BCS of 2 or less. Emaciation (Beef BCS = 1, dairy BCS = 1.0) or near-emaciation (Beef BCS = 2, dairy BCS = 1.5) was observed in 13.3% of dairy cows and 3.9% of Beef cows. Among Beef cattle, 15.1% of cows and 15.4% of Bulls were considered lame. In contrast, 44.7% of dairy cows and 26.1% of dairy Bulls were lame. Ocular neoplasia (cancer eye) was observed in only 0.6% of Beef cows, 0.3% of Beef Bulls, 0.3% of dairy cows, and 0.0% of dairy Bulls. However, among animals with ocular neo-plasia, it was cancerous in 34.4% of Beef Bulls, 48.0% of dairy cows, and 73.3% of Beef cows. In conclusion, nu-merous quality defects are present in market Beef and dairy cattle selling at auction in the Western United States, which could influence their value at auction.