Breed Of Dam Research Articles

Factors Affecting Birth Weight And Growth Rate In Friesian X Bunaji Calves

Calving records from 1984 - 1989 were studied to determine the influence of rearing method, sex of calf, season of birth, dam breed and year of birth on body weight at birth, 3,6 and 12 months of age in Friesian x Bunaji calves. The mean weights of calves at birth, 3, 6 and 12 months of age were 22.0, 68.2, 96.7 and 137.4 kg, respectively. Sex of calf had a significant effect, with male calves being heavier than the females by 1.2, 5.9 and 9.7 kg at birth, 3 and 6 months of age respectively. The effect of season of birth on calf body weights was not significant except at 6 months of age, when calves born during the wet season were heavier (P<0.01) than those born in the harmattan period by 9.5 kg. Year of birth had a highly significant effect (P<0.01) on calf weights from birth to yearling. Method of rearing and dam breed had no significant influence on all the weights. The results suggest the need to develop correction factors for standardisation of weight records when comparing dams on the basis of body weights of their calves.

Yield And Composition Of Milk And Their Relationship With Preweaning Lamb Growth In The Yankasa Ewes And Their Crosses With The Sires Of Suffolk X Wenselydale Breed

Milk production in Yankasa ewes and their crosses with the sires of Suffolk/Wenselydale breed was measured at weekly intervals following oxytocin administration. The influence of age and breed of dam on yield and composition were investigated and the relationships between milk yield, milk composition and lamb weight gain were determined. Daily milk intake production in Yankasa and crossbred ewes averaged 348.1 and 505.7g respectively. The mean fat and protein content over the entire lactation were 5.86 and 5.07% for Yankasa and 6.19 and 4.96% for crossbreds, respectively. Crossbred ewes produced significantly higher (P<0.01) milk than Yankasa at all stages of lactation. Age of the ewe had significant effect (P<.05) on total milk yield but not on fat or protein content. The correlations between lamb weight and milk yield at various stages of lactation ranged from 0.51 to 0.66 and 0.62 to 0.71, respectively, for Yankasa and crossbred lambs. Sheep milking can make a significant contribution to rural daily production in Nigeria.

Purebreeding with sexed semen and crossbreeding with semen from double-muscled sires to improve beef production from dairy herds: Live and slaughter performances of crossbred calves

The use of sexed semen to produce purebred replacement heifers allows a large proportion of dairy cows to be mated to beef sires, and quantitative and qualitative improvements to be made to beef production from dairy herds. The major dairy and beef breeds are undergoing rapid genetic improvement as a result of more efficient selection methods, prompting a need to evaluate the meat production of crossbred beef × dairy cattle produced using current genetics. As part of a large project involving 125 commercial dairy farms, we evaluated the combined use of purebreeding with sexed semen and crossbreeding with semen from beef sires, particularly double-muscled breeds. A survey of 1,530 crossbred calves revealed that, whereas purebred dairy calves are destined almost exclusively for veal production, beef × dairy crossbred calves are also destined for beef production after fattening on either the dairy farm of birth or by specialized fatteners. In veal production, compared with Belgian Blue-sired calves (taken as the reference), double-muscled INRA 95-sired calves had a lighter slaughter weight (303 vs. 346 kg), but a greater dressing percent (62.3 vs. 58.4%). Limousin (also known as Limousine)-sired calves had a smaller average daily gain (1.26 vs. 1.34 kg/d), and lighter slaughter (314 vs. 346 kg) and carcass weights (182 vs. 201 kg). Last, Simmental-sired calves had a similar growth rate, but lighter carcass weight (177 vs. 201 kg), smaller dressing percentage (55.3 vs. 58.4%), and smaller muscularity scores (3.25 vs. 3.72). In the case of young bulls and heifers fattened on the dairy farm of birth, Belgian Blue-, Piemontese (also known as Piedmontese)-, and Limousin-sired calves performed similarly; the only exception was that Piemontese-sired calves had a greater dressing percentage. Belgian Blue- and Limousin-sired calves performed similarly when fattened by specialized beef producers. In both veal and beef production, the effects of dam breed were less important than sire breed. Considering the entire project, we can conclude that the combined use of sexed semen for purebreeding and conventional beef semen for terminal crossbreeding improves meat production from dairy herds, especially when the sires are double-muscled beef breeds.

Genetic analysis of survival potential of Boer x Central Highland goats under semi-intensive management

Kid survival is very critical to be profitable in goat production. Thus, this study was conducted to identify genetic and non-genetic factors affecting the survival rate of Boer x Central Highland goat and to estimate genetic parameters for survival using linear animal and Weibull proportional hazard model. Data collected from the Sirinka goat breeding station were utilized for this study. Survival analysis was conducted with a Weibull proportional hazard model using Survival Kit version 6.1 software. The genetic parameters for survival traits were estimated using both Survival Kit fitted sire model and ASREML software fitted animal model with logit function. Four models for survival traits were fitted in order to optimize the model for each trait in the animal model. The log-likelihood ratio test was used for selecting the best-fitted model. The proportion of right-censored kids up to 3, 6 and 12 months of age was 77.8, 66.2 and 57.9 %, respectively. From the total death, about 73.1 % of death occurred up to 140 days of age. Gastrointestinal parasites, septicemia, pneumonia are the leading causes of death. Birth type, birth weight, dam breed and year of birth are the most important risk factors for kid mortality. Based on selected linear animal models, total heritability (h2t) estimates for the survival of kids at 3, 6 and 12 months of age were 0.006, 0.096 and 0.098, respectively. The maternal permanent environmental effect explains 6% of the phenotypic variation in survival up to weaning age. However, the impact of the maternal effect on post-weaning survival was found to be negligible. The genetic correlation between birth weight and survival to yearling age was 0.55 ± 0.15. The heritability estimates for survival at 3, 6 and 12 months of age from the Weibull proportional hazard model were 0.10, 0.13 and 0.18, respectively. As both pre- and post-weaning survival traits are economically important traits, including in the selection index of the breeding program would be paramount. Besides selection, using a local goat as a dam line and improving management in the flock would be an option to improve the survival of kids.

Short communication: Pure-breeding with sexed semen and crossbreeding with semen from double-muscled sires to improve beef production from dairy herds: Weight and value of calves

The use of sexed semen to produce purebred replacement heifers allows a large proportion of dairy cows to be mated to double-muscled sires and for quantitative and qualitative improvements to be made to beef production from dairy herds. A survey of 1,285 crossbred calves showed that they are destined not only for veal production (like purebred dairy calves) but also for beef production. Crossbred calves obtained from Belgian Blue sires (sold on average at 34 d of age and 64 kg of weight) had a higher market value (€363/calf) than those obtained from double-muscled INRA 95 sires (€297/calf, used for veal production) and from Limousin sires (€216/calf for veal and €271/calf for beef production). As a sire breed, Simmental did not differ significantly from Belgian Blue, but as a dam breed, the crossbred calves fetched a higher price (€5.11/kg) than when Holstein was the dam breed (€4.50/kg). Compared with heifer calves, crossbred bull calves at sale were younger (34.1 vs. 37.2 d) and heavier (64.0 vs. 62.6 kg of live weight), fetched a higher price (€5.13 vs. €4.99/kg), and had a greater value (€328 vs. €312/calf). As the value of purebred dairy calves was about €80 to €100/calf, we are able to confirm that the combined use of sexed semen for pure-breeding and conventional beef semen for terminal crossbreeding can increase the income from dairy farms, especially when the sires are double-muscled beef bulls.

Dual energy X-ray absorptiometry precisely and accurately predicts lamb carcass composition at abattoir chain speed across a range of phenotypic and genotypic variables

Dual energy X-ray absorptiometry (DEXA) is an imaging modality that has been used to predict the computed tomography (CT)-determined carcass composition of multiple species, including sheep and pigs, with minimal inaccuracies, using medical grade DEXA scanners. An online DEXA scanner in an Australian abattoir has shown that a high level of precision can be achieved when predicting lamb carcass composition in real time. This study investigated the accuracy of that same online DEXA when predicting fat and lean percentages as determined by CT over a wide range of phenotypic and genotypic variables across 454 lambs over 6 kill groups and contrasted these results against the current Australian industry standard of grade-rule (GR) measurements to grade carcasses. Lamb carcasses were DEXA scanned and then CT scanned to determine CT Fat % and CT Lean %. All phenotypic traits and genotypic information, including Australian Sheep Breeding Values, were recorded for each carcass. Residuals of the DEXA predicted CT Fat % and Lean %, and the actual CT Fat % and Lean % were calculated and tested against all phenotypic and genotypic variables. Excellent overall precision was recorded when predicting CT Fat % (R2 = 0.91, RMSE = 1.19%). Small biases present for sire breed, sire type, dam breed, hot carcass weight and c-site eye muscle area could be explained by a regression paradox; however, biases among kill group (−0.73% to 1.01% for CT Fat %, −1.48% to 0.76% for CT Lean %) and the Merino sire type (0.36% for CT Fat %, −0.73% for CT Lean %) could not be explained by this effect. Over the large range of phenotypic and genotypic variation, there was excellent precision when predicting CT Fat % and CT Lean % by an online DEXA, with only minor biases, showing superiority to the existing Australian standard of GR measurements.

419 Academic performance and views toward community service from students engaged in service learning through a beef production course

Abstract Experiential learning is a feature common to post-secondary agricultural education. Similar to experiential learning opportunities, incorporation of service learning into post-secondary coursework is being encouraged more often. Our objective was to determine how community engagement and introduction of real-world problems in a species-specific production course would affect student performance and outlooks on community service. This experiment was conducted as a completely randomized design within the beef cattle production class during the spring 2019 semester at Tarleton State University. Thirty-eight students were enrolled in the course across two laboratory sections. Students in the first laboratory section were used as a control group. In the control, students were asked to draw from a selection of possibilities a description of herd size, sire and dam breed type, and county. Groups were asked to develop a management plan for a commercial cow-calf operation. Students in the second laboratory section were asked to brainstorm the most prevalent barriers to implementation of best management practices in cow-calf production. Groups were randomly assigned to each topic and were tasked with developing a tri-fold brochure addressing the barrier. They were instructed that this was being done as a service to the greater beef community and would be evaluated by industry representatives. Students in CON had more (P < 0.05) students that reported performing community service weekly or monthly prior to the study than TRT. Groups were similar (P ≥ 0.41) in their assessment of community needs and the role of college students in community service. Likewise, CON and TRT had similar (P ≥ 0.41) responses in having less time available for coursework and their service contributing to the betterment of the overall community. Results are interpreted to mean that incorporation of service learning opportunities does not influence student views on community service.

Beef Production Systems with Steers of Dairy and Dairy × Beef Breeds Based on Forage and Semi-Natural Pastures.

Simple SummaryTwo-thirds of Swedish beef originates from dairy cows and their offspring, and the vast majority of the calves are of pure dairy breeds. At the same time, European Union, EU, and national agri-environmental payments for grazing biodiverse semi-natural pastures are an important source of income for Swedish beef producers. This study investigated whether beef production from dairy cow offspring based on semi-natural pastures could be improved using beef breed bulls as sires, instead of dairy bulls. Dairy × beef breed steers were compared with pure-bred dairy steers in two different production systems, both based on forage and semi-natural pastures, but varying the birth season, indoor feed intensity, number of grazing periods, and slaughter age. There were no differences between the breeds in feed efficiency or liveweight gain during rearing, but there were differences in carcass weight and composition. Based on these results, we concluded that higher-quality carcasses could be obtained if beef breed sires were used in production systems with semi-natural pastures.This study compared animal performance and carcass characteristics in steers born to a dairy breed dam and a dairy or beef breed sire allocated to one out of two production systems, both including grazing semi-natural pastures during summer. Spring-born groups comprising 16 purebred dairy (D) steers and 16 dairy × Charolais crossbreeds (C) were allocated to moderately high indoor feed intensity with slaughter at 21 months of age (H), while two corresponding autumn-born groups of 16 D and 16 C animals were allocated to low indoor feed intensity with slaughter at 28 months of age (L). The animals were mainly fed grass-clover silage while housed. The H steers grazed semi-natural pastures for one summer, whereas the L steers grazed semi-natural pastures for two summers. From weaning to slaughter, liveweight gain was 0.94 and 0.77 kg day−1 for H and L steers, respectively (p < 0.0001), with no breed effect on weight gain. However, C carcasses had a higher weight, conformation score, and proportion of high-valued retail cuts than D carcasses (p ≤ 0.004). Moreover, conformation differed more between LC and LD than between HC and HD. From this study on forage and pasture-based beef production, we concluded that breed had no effect on the performance of living animals, but that dairy × beef crossbred steers produced heavier and higher-quality carcasses than pure-bred dairy steers.

Cow-level risk factors for reproductive tract disease diagnosed by 2 methods in pasture-grazed dairy cattle in Ireland

The cow-side diagnosis of reproductive tract disease (RTD) involves identifying the presence of purulent vaginal discharge (PVD) and ultrasonographic endometritis (UE). The objectives of our study were to obtain prevalence estimates for RTD diagnosed by 2 methods (PVD and UE scoring) and to investigate the risk factors for increased probability of RTD if these methods are used in isolation or in combination. Our retrospective observational cohort study tested the hypothesis that RTD assessed by 2 methods would have similar risk factors, and that those would be mainly cow- and calving-related factors. We analyzed data from 5,049 pre-breeding examinations (PBE) from 2,460 spring-calved cows on 8 farms between 2014 and 2018. Cow-related details assessed were days in milk at PBE, breed, lactation number, dry period length, body condition score at calving and PBE, 305-d milk yield, predicted transmitting ability for production and fertility, the presence of a corpus luteum at PBE, and positive diagnosis the previous year. Calving details assessed were type of sire, calf sex, twinning, stillbirth, calving difficulty score, and retained fetal membranes. We conducted statistical analyses using 4 multivariable logistic regression models to identify the risk of RTD diagnosed by (1) PVD in isolation, (2) UE in isolation, (3) the presence of either PVD or UE; and (4) the presence of both PVD and UE. We accounted for herd, cow, and year as random effects in all 4 models. The overall prevalence of RTD in models 1, 2, 3, and 4 were 7.5, 6.7, 11.6, and 2.6%, respectively. Days in milk at PBE, the interaction between days in milk and retained fetal membranes, twinning, and the predicted transmitting ability for calving interval were consistently significant risk factors for positive scores in all 4 models. Considerable calving difficulty [adjusted odds ratio (AOR) = 13.64], Holstein Friesian dam breed (AOR = 2.58), first lactation (AOR = 2.39), and body condition score at PBE (AOR = 1.64) were risk factors for a positive PVD score but not for a positive UE score. Fifth lactation (AOR = 1.69), a beef-sired calf (AOR = 1.46), and the absence of a corpus luteum at PBE (AOR = 1.57) were risk factors for a positive UE score but not for a positive PVD score. These results support the hypothesis that most of the risk factors for PVD and UE are the same but some are distinctly different, implying that in some instances the 2 methods diagnose separate components of the RTD complex.

Estimation of economic weights for number of teats and sperm quality traits in pigs.

Accurate predictive modelling facilitates efficient and effective trait selection in animal breeding and can decrease costs while maximizing profits when raising economically important animals. The objective of this study was to extend a previously developed bioeconomic model and computer program to calculate the marginal economic values (MEVs) and economic weights (EWs) for direct and maternal pig traits affected by new reproductive traits, namely the number of sow functional teats (NFTs) and boar sperm quality traits (SQTs) that included sperm volume, sperm concentration, motility percentage and percentage of abnormal spermatozoa. The MEV of NFTs represented the cost differences between naturally and artificially reared piglets until weaning and the cost differences between naturally and artificially reared finished animals. The MEVs of SQTs expressed the saved costs for artificial insemination, assuming a decreased price per insemination dose when improving the SQTs. The absolute and relative EWs for the newly defined complex of traits in the breeding objectives for pig breeds involved in the Czech national three-way crossing system (Czech Large White [CLW], Czech Landrace [CL] and Pietrain [PN]) were calculated using gene flow methods. The NFT trait was included only for dam breeds, and the relative EW averaged 3.6% of the total economic importance based on the genetic standard deviations of all 19 simultaneously evaluated traits in CLW and CL breeds. The relative EWs of the four SQTs comprised 2.0% of the total economic importance of the 19 traits in the CLW and CL dam breeds and 8% of the total economic importance of the 18 traits in the PN sire breed. Therefore, inclusion of the NFTs for dam breeds and SQTs for sire breeds in the breeding goal is recommended to aid in obtaining ideal outcomes with optimal economic values.

Estimates of genetic parameters and heterosis for birth weight, one-month weight and litter size at birth in five goat breeds

Records of birth weight, one-month old weight and litter size at birth, from 19,887 kids were collected from 1979 to 2000 at the National Goat Centre of Tlahualilo, located in northern Mexico. Local goats of a non-defined breed were recurrently crossed with imported sires of Granadina, Nubian, Alpine, Saanen and Toggenburg breeds. After editing, the data comprised of 12,641 kids and a pedigree file of 14,762 animals. Estimates of (co)variance components, heritability and repeatability of the aforementioned traits were obtained using a mixed model that included the fixed effects of sex, litter size, age of the dam at kidding, season-year of kidding, breed group, level of upgrading of the dam and the interaction between the breed of dam and breed of sire, as well as direct genetic, maternal genetic and maternal permanent environment random effects. The Granadina kids had the lowest birth and one-month weights. Estimates of direct heritability of the five breeds ranged from 0.202 to 0.510, 0.036 to 0.414 and 0.034 to 0.154 for birth weight, weight at one month of age and litter size, respectively, with several estimates for LS being non estimable. Maternal heritabilities ranged from 0.154 to 0.278 for birth weight and 0.023 to 0.378 for weight at one month of age. Only two estimates of maternal heritability were estimated for litter size and both were not significantly different from zero. Correlations between direct and maternal genetic effects were all negative for birth weight and litter size. Genetic and maternal correlations among all traits, estimated in the overall multi-breed population, were not significantly different from zero. These estimates are generally within the range of values reported for other breeds. A negative heterosis was found for both weight traits in the case of Granadina sires. Our estimates for birth weight and litter size are higher than the values reported in other studies with meat breeds.

The effect of Piétrain sire on the performance of the progeny of two commercial dam breeds: a pig intervention study

Genetic evaluation of Piétrain sires in Flanders occurs under standardized conditions, on test stations with fixed dam breeds, standardized diets and uniform management practices. As environmental conditions vary on commercial farms and differ from the test stations, this study aimed at understanding to what extent the sire, the dam breed and the interaction between both affects the translation of breeding values to practice. Dams of two commercial breeds were inseminated with semen from one of five different sires selected for contrasting breeding values (daily gain, feed conversion ratio and carcass quality). For each sire by dam breed combination, six pen replicates (with three gilts and three barrows per pen) were evaluated for growth performance from 9 weeks of age (20 kg) to slaughter (110 kg), and for carcass and meat quality. In our experimental setup, both sire and dam breed affected growth, carcass and meat quality traits. No significant sire×dam breed interactions on performance could be detected. Though a tendency for interaction on average daily feed intake between 20 and 110 kg (P=0.087), and on pork colour (lightness) (P=0.093) was present. In general, offspring of all tested sires behaved similarly in both dam breeds, indicating that estimated breeding values for Piétrain sires determined in one dam breed are representative in other dam breeds as well.

Economic weights of maternal and direct traits of pigs calculated by applying gene flow methods

Multiple trait selection indexes in pig breeding programmes should take into account the population structure and time delay between parent selection and expressions of traits in all production levels next to the trait impacts on economic efficiency of production systems. Gene flow procedures could be used for the correct evaluation of maternal and direct traits of pig breeds involved in breeding or crossbreeding systems. Therefore, the aim of this study was to expand a previously developed bioeconomic model and computer program to calculate the marginal economic values by including a gene flow procedure to calculate the economic weights for maternal and direct traits in pig breeds. The new program was then applied to the three-way crossbreeding system of the Czech National Programme for Pig Breeding. Using this program, the marginal economic values of traits for dam breeds Czech Large White in the dam position and Czech Landrace in the sire position, and for the sire breed Pietrain were weighted by the number of discounted gene expressions of selected parents of each breed summarised within all links of the crossbreeding system during the 8-year investment period. Economic weights calculated in this way were compared with the approximate economic weights calculated previously without a gene flow procedure. Taking into account the time delay between parent selection and trait expression (using discounting with half-year discount rates of 2% or 5%) and including more than one generation of parent progeny had little impact on the relative economic importance of maternal and direct traits of breeds involved in the evaluated three-way crossbreeding system. These results indicated that this gene-flow method could be foregone when estimating the relative economic weights of traits in pig crossbreeding systems applying artificial insemination at all production levels.

Crossbreeding applied to systems of beef cattle production to improve performance traits and carcass quality

Crossbreeding represents an important technique to improve growth, beef quality and adaptability in beef production systems in tropical countries. The aim of this study was to evaluate sire and dam breed effects on performance and carcass traits of crossbred cattle produced in a tropical environment. Heifers and steers were evaluated during the pre-weaning, the post-weaning (n = 173) and the finishing phase (n = 123). Animals were produced by mating Nellore (N_N), Angus × Nellore (A_N) and Caracu × Nellore (C_N) dams with Braford, Charbray and Caracu sires. After weaning, animals were raised grazing on Marandu grass for 12 months; thereafter they were housed in individual pens and finished in a feedlot, receiving a total mixed ration. Ultrasound carcass evaluations were performed to determine ribeye area (R_A), backfat thickness (B_T) and rump fat thickness (R_T). A_N progeny were heavier at birth than N_N (P < 0.05), and Braford progeny had greater birth BW than Caracu (P < 0.05). Greater weaning BW was observed in the A_N and C_N offspring compared to N_N (P < 0.01). Greater average daily gain during the post-weaning period was verified in the N_N progeny compared to C_N (P < 0.05). No dam or sire breed effects were observed for BW at the end of the post-weaning period (P > 0.05). Progeny of N_N cows had greater B_T (P < 0.05) and R_T (P < 0.01) at the end of the post-weaning period in relation to C_N. Greater R_A was observed in the Caracu progeny than in the Braford (P < 0.05), which showed greater R_T than the Charbray progeny at the end of the post-weaning period (P < 0.05). No dam or sire breed effects were verified for final BW at the feedlot or for feed efficiency traits (P > 0.05). A_N progeny were superior in final B_T compared to C_N (P < 0.01), and Braford progeny had greater R_T at the end of finishing than Charbray (P = 0.05). The use of crossbred dams allows an increase in productivity until weaning, but this is not maintained in the post-weaning and finishing periods. The use of Braford sires produces similar growth performance in the different stages of the production system to those seen with Charbray and Caracu sires but generates animals with higher fat thickness at the end of finishing, which may improve carcass quality and commercial value.

Rambouillet and Romanov reciprocal breed effects on survival and growth traits of F1 lambs and on reproductive traits of F1 ewes.

Objectives were to estimate reciprocal effects of Romanov and Rambouillet breeds on survival, growth, and reproductive traits of F1 progeny and direct breed effects (Suffolk and Composite - ½ Columbia, ¼ Hampshire, and ¼ Suffolk) on survival and growth traits of the subsequent terminally sired lambs. Mature Rambouillet ewes (n = 243) were exposed to 20 Romanov rams over two seasons producing 621 lambs for evaluation of growth and survival traits with 274 F1 ewes being evaluated for reproduction traits through 4 yr of age. Similarly, mature Romanov ewes (n = 116) were exposed to 20 Rambouillet rams producing 601 lambs for evaluation of growth and survival traits with 176 F1 ewes being evaluated for reproduction traits through 4 yr of age. A total of 433 of those F1 ewes produced 3,431 lambs (1,552 litters) from 1,634 exposures to terminal sires over 4 yr. Terminal sires consisted of 38 Suffolk and 44 Composite rams. Reciprocal crossbred ewe lambs were produced from dramatically different uterine and neonatal environments, with litter size at birth from Romanov dams exceeding those from Rambouillet dams by 1.52 lambs (P < 0.001) and birth weight of lambs from Romanov dams averaged 3.41 kg compared with 4.26 kg from Rambouillet dams. Differences in BW were still evident at 140 d (P < 0.001) for dam-reared lambs. However, reciprocal ewe first breeding BW of both types were similar (P = 0.38). Minimal differences were observed in performance of reciprocal cross ewes through 4 yr for productivity, longevity, or progeny growth and survival. One exception was BW at 140 d where an interaction of dam breed with terminal sire breed reached significance for both dam-reared (P = 0.05) and nursery-reared (P = 0.02) lambs. This interaction was due to the lower weight of Composite-sired lambs out of reciprocal cross ewes born from Rambouillet dams. Composite rams increased number born (P < 0.01) and number weaned (P < 0.05) of the reciprocal cross ewes. Suffolk rams increased (P < 0.001) BW and growth rates from birth to 140 d of terminal progeny. Thus, there were little cumulative differences accrued over the 4 yr and no differences were detected for cumulative kilogram of lamb generated at 140 d per ewe exposed. The practical outcome of this evaluation was that performance levels of both types of Romanov crossbred ewes was similar allowing the industry to produce the desired crossbred ewes without needing large purebred ewe flocks of the less numerous Romanov breed.

284 Feed intake of progeny of contrasting sire and dam breed and dam origin.

284 Feed intake of progeny of contrasting sire and dam breed and dam origin.

Comparison of Mutton Charollais Lambs and Their Cross Lambs Born from Indigenous Fat Tailed and F1 Prolific Breed Ewes

The objective of this study was to evaluate the effects of dam breed on lambs sired by Charollais rams and purebred Charollais lambs obtained via embryo transfer. Frozen Charollais semen and embryos, used to obtain crossbreed and purebred Charollais lambs, were imported from elite flock with pedigrees and progeny test in Canada.The study was conducted on the crossbred Charollais lambs born from Tushin, and Romanov F1 ewes (Romanov × Morkaraman), and Charollais lambs born from Awassi, Morkaraman and Tushin surrogate ewes. The data was collected on 61 lambs (23 Charollais: CH, 20 Tushin × Charollais: F1 CH and 18 Charollais × Romanov F1:COR) from birth to weaning. Average weights at birth for CH, F1 CH and COR lambs were 4.32 ± 0.18 kg, 4.17 ± 0.18 kg, 3.18 ± 0.19 kg and at the age of 60 days were 21.20 ± 1.07 kg, 20.94 ± 0.84 kg, 18.13 ± 0.91 kg, respectively. The genotype of dams significantly affected birth and weaning weights of crossbred lambs, but not average daily live weight gain (ADG). Litter size had constant significant effect on the traits evaluated. Survival rates of crossbred lambs from birth to weaning were affected by the dam genotype. Birth weights and survival rates of CH lambs born from embryo transfer were affected by recipient genotypes and Awassi ewes were found to be the best surrogate mothers.

Factors affecting differences between birth weight of littermates (BWTD) and the effects of BWTD on lamb performance

The objectives of this study were to determine factors affecting lamb birth weight (BWT) and differences between BWT of the largest and smallest littermates (BWTD) and to assess the relative importance of BWT and BWTD on lamb survival and growth to weaning. Records from twin (n = 5369) or triplet (n = 1664) litters born on pasture were utilised. Breeds included Coopworth, Romney, Perendale, composite and Texel. Ewe and sire breed, age and weight of the dam, sex, and number of lambs born (NLB) affected BWT. Neither embryo loss nor ovulation pattern (i.e. all ova released from one ovary or some from each) were associated with BWT. Dam weight and NLB affected BWTD but dam age, sire or dam breed did not. Loss of an embryo reduced BWTD, and BWTD was lower when the ewe ovulated from both ovaries versus only one ovary for twins, but not triplets. Whereas BWT was moderately heritable (h2 = 0.20), BWTD was not heritable (h2 = 0.003). Lamb survival was positively associated with BWT. Lambs with BWTD > 1.3 kg were less likely to survive (73.3%) than those from litters of smaller BWTD (range 82.8–85.7% survival). Growth rate of twin and triplet lambs was positively associated with BWT. Surprisingly, lambs from litters with moderately high BWTD had slightly greater (approximately 3%) growth rate than those from lambs of low to intermediate BWTD. Thus, while large BWTD were negatively associated with survival, BWT itself, which was moderately heritable, appeared to be a stronger driver of lamb survival and average daily gain.

FACTORS INFLUENCING THE GROWTH PERFORMANCE OF CALVES FROM TERMINAL CROSSES OF THREE LOCAL BREEDS WITH SOME IMPORTED BREEDS IN THE WESTERN HIGHLANDS OF CAMEROON

The aim of this study was to investigate the effect of factors influencing growth performances (live weightand average daily weight gain) of 374 calves from terminal crossing between indigenous breeds (Gudali,White Fulani and Banyo) and three exotic breeds (Brahman, Brangus and Holstein). Data have beencollected from 1993 to 2008 at the Agricultural Research Institute for Development (IRAD)-Bambui stationwestern highlands of Cameroon. Growth performances were significantly influenced by several factorsunder study. Hence, pre-and post-weaning live weight and average daily gain (ADG) were significantlyinfluenced by all the factors, excepted age and breed of dam, age and breed of sire for post weaningperformance. Sex x breed interaction was significant at 90 days while season x breed interaction influencedall pre-weaning traits. Live weight varied according to season, month and year of calving. Calves born inthe dry season were heavier than those born in the rainy season by 5.38% and 6.03% at weaning and 720days respectively. Crossbred calves generally performed better than local breed for all traits considered.Male calves outperformed female by 5.48%, 5.19% and 12.66% at birth, weaning (205 days), and 720 daysrespectively. Middle-aged parents were found to account for heavier calves at both birth weight and finalweight while very young and very old parents produced lighter calves for all growth parameters studied.ADG also showed the same tendency as live weight and varied with all the factors under study. Theimprovement of husbandry system may permit the calves to better express their growth potential in thewestern highlands of Cameroon

Growth performance, carcase characteristics and meat quality of crossbred bulls and heifers from double-muscled Belgian Blue sires and Brown Swiss, Simmental and Rendena dams

Growth, conformation, carcase and meat quality traits of crossbred calves obtained in the Alps from selected Belgian Blue sires (BB) and Brown Swiss (BS), Simmental (Si) and Rendena (Re) dams were studied, emphasising differences on dairy and dual purpose maternal breed. Six pens with five heifers (3 BB × BS, 1 BB × Si, 1 BB × Re) and six pens with four young bulls (2 BB × BS, 1 BB × Si, 1 BB × Re) were used. In total 53 crossbred calves were tested: 30 from BS dams and 23 from dual purpose (12 from Si and 11 from Re dams). Growth performances were measured, carcases were scored for muscle conformation and fatness, the fifth rib was dissected, and the Longissimus thoracis (LT) was analysed. The maternal breed had significant effects when the calves from dairy cows (BB × BS) were compared to those of the dual purpose breeds (BB × Si and BB × Re), as at slaughter the former were 1.2% taller, 6.0% less in vivo muscle score, 5.0% less carcase muscle score, with a 13% greater proportion of bone in the rib, and their LT had 12.5% less drip losses, but 3% greater cooking losses and 25% greater shear force. It was concluded that when using a BB as a sire, the dam breed has influence on the growth performance traits of the derived crossbreds, but the major influence would regard the carcase and meat quality traits. In the Alps, these differences are reflected in different sold prices of the crossbred calves from dairy and dual purpose breeds at local auctions.