Crossbreeding Effects Research Articles

Effect of crossbreeding and dietary neutral detergent fiber (NDF) levels on feed intake, nutrient digestibility, rumen parameters and nitrogen retention of beef cattle

This experiment sought to evaluate the influence of varying levels of neutral detergent fiber (NDF) in the diet on feed intake, nutrient digestibility, rumen conditions, and nitrogen retention in crossbred cattle. Beef cattle aged 18 months were organized into groups using a 2x (4x4) Latin square design. The NDF levels investigated were 47%, 51%, 55%, and 59% of dry matter (referred to as NDF47, NDF51, NDF55, and NDF59 treatments, respectively). While dry matter (DM) consumption per 100 kg body weight (BW) did not exhibit significant differences between treatments, Charolais crossbred cattle (2.16 kg DM) demonstrated higher intake than Black Angus crossbred cattle (2.04 kg DM). Metabolizable energy intake in Charolais crossbred cattle significantly differed from that in Black Angus crossbred cattle (17.6 and 16.7 MJ/100 kg BW, respectively). Regarding NDF treatments, NDF47 did not differ from NDF51 and NDF55, but it was significantly higher (P<0.05) than the NDF59 treatment (18.1, 17.3, 17.1, and 16.0 MJ/100 kg BW, respectively). Although dry matter and organic matter digestibility did not significantly differ between Charolais and Black Angus crossbred cattle, variations were noted among treatments (P<0.05). Specifically, DM digestibility of NDF47 (62.8%) was significantly higher than NDF59 (55.4%), with no significant differences observed for NDF51 (59.8%) and NDF55 treatments (58.9%). Rumen pH, N-NH3, and total volatile fatty acid concentrations at 0h and 3h post-feeding did not exhibit significant differences (P>0.05) in this study. However, nitrogen retention in Black Angus crossbred cattle was significantly lower than in Charolais crossbred cattle (0.124 and 0.166 g/kg BW, respectively). Across treatments, nitrogen retention values were numerically higher (P>0.05) in NDF47, NDF51, NDF55, and NDF59 treatments (0.166, 0.148, 0.139, and 0.126 g/kg BW, respectively). In summary, this study determined that Charolais crossbred cattle displayed increased feed intake, crude protein digestibility, and nitrogen retention compared to Black Angus crossbred cattle. Furthermore, a dietary NDF level of 55% was suggested as suitable for practical use in terms of feed utilization by farmers. Keywords: Forage, crossbreeding, rumen fermentation, and ruminant. Abbreviations: DM: dry matter, OM: organic matter, CP: crude protein, NDF: neutral detergent fiber and ME: metabolic energy, BW: body weight. NDF

Mating compatibility and offspring traits evaluation among different strains of Tenebrio molitor.

The fast-growing sector of insects for food and feed stimulates researchers and the industry to explore uncharted territories, such as insect breeding, to improve economically important insect fitness traits. The yellow mealworm, Tenebrio molitor L., is one of the most thoroughly studied insect species as food and feed. However, data on mating compatibility and the effect of cross-breeding between different strains on the performance and fitness of the hybrids are scarce. In the present study, we comparatively evaluated the mating compatibility between two T. molitor inbred strains (Greek and Italian) and their outbred strains, i.e., Italian (♀)-Greek (♂) and Greek (♀)-Italian (♂), as well as the performance of their hybrid offspring. Based on the results, there is good mating compatibility among adults of the strains tested. Offspring performance, quantified as larval survival and final larval weight, followed a similar pattern among the crossings examined. Even though differences were insignificant, the outbreeding of females of the Italian strain resulted in a higher cumulative number of eggs and hatching rate and higher offspring weight. The present study sheds light on the mating compatibility of different T. molitor strains and their hybrids' economically important life table characteristics to take the mass production of insects one step further.

The impact of using different ancestral reference populations in assessing crossbred population admixture and influence on performance.

Crossbreeding is a process in which animals from different breeds are mated together. The animals produced will exhibit a combination of both additive and non-additive genetic improvement from parental breeds that increase heterozygosity and negate inbreeding depression. However, crossbreeding may also break up the unique and often beneficial gene combinations in parental breeds, possibly reducing performance potential as the benefits of heterosis depends on the type of crossbreeding systems used and heritability of the traits. This effect of crossbreeding, especially on the genome architecture, is still poorly understood with respect to 3-breed crossbreeding systems. Thus, this study examined variation in genomic ancestry estimations relative to pedigree-based estimations and correlated breed composition to key production and health traits. Two rotational crossbred populations, referenced as ProCROSS and Grazecross were assessed and totaled 607 crossbred cattle. ProCROSS is a product of rotational crossbreeding of Viking Red (VKR), Holstein (HOL), and Montbeliarde (MON). In contrast, Grazecross consists of Viking Red (VKR), Normande (NOR), and Jersey (JER). Both breeding programs were aimed at capitalizing on the positive effect of heterosis. The VKR is a marketing term for Swedish Red, Danish Red, and Finnish Ayrshire breed which complicated breed determination. Therefore, genomic breed composition estimates were compared using two different representations of VKR, one of which was based on parents used in the crossing system and a second based on genotypes from the ancestral breeds that comprise VKR. Variation of breed composition estimates were assessed between pedigree and genome-based predictions. Lastly, Genomic estimations were correlated with production and health traits by comparing extreme performance groups to identify the relationship between breed ancestry and performance. With the exception of the JER breed composition in Grazecross, all other estimates of the purebred contribution to the ProCROSS and Grazecross showed a significant difference in their genomic breed estimation when using the VKR ancestral versus the VKR parental reference populations for admixture analysis. These observations were expected given the different relationship of each VKR representation to the crossbred cattle. Further analysis showed that regardless of which VKR reference population was used, the degree of MON and HOL breed composition plays a significant role in milk and fat production in ProCROSS, while the degree of VKR and NOR ancestry were related to improved health performance in Grazecross. In all, identifying the most appropriate and informative animals to use as reference animals in admixture analysis is an important factor when interpreting results of relationship and population structure, but some degree of uncertainty exists when assessing the relationship of breed composition to phenotypic performance.

Effect of Crossbreeding on Growth Performance of Improved Horro Crosses with Koekoek and Kuroiler Chicken Breeds

Effect of Crossbreeding on Growth Performance of Improved Horro Crosses with Koekoek and Kuroiler Chicken Breeds

Crossbreeding impacts on caecal bacterial count and antibody titres in chickens

ABSTRACT 1. A crossbreeding experiment was conducted using 20 sires and 120 dams from each Fayoumi (F) and Rhode Island Red (R) breeds. The F1 chicks of ½F½R and their reciprocal ½R½F crosses were used to estimate direct, maternal and heterotic effects. 2. The caecal bacterial counts of Salmonella typhimurium and Enterococcus faecium and the IgA, IgG and IgM antibody titres were determined. Chicks of each genetic group (120 birds) were divided into three groups (40 birds per group) and chicks of the first group were assigned as the control group, while the second group was inoculated with S. typhimurium and E. faecium at 7 and 10 d of age (106 cfu/chick) and the third was inoculated with S. typhimurium at 10 d of age (106 cfu/chick). 3. The generalised least square procedure was used to estimate cross-breeding effects. The S. typhimurium counts in the R breed was highly significant, followed by ½F½R cross, ½R½F cross, and F breed. The differences among genetic groups in E. faecium counts and caecal pH was not significant. The estimates of IgA, IgG, and IgM antibody titres were highly significant in the F breed, followed by ½R½F cross, ½F½R cross, and the R breed. 4. The estimates of direct additive effects were highly significant F breed for the counts of S. typhimurium and antibody titres of IgA, IgG, and IgM. The maternal effects were highly significant F breed for S. typhimurium, E. faecium count, and antibody titres of IgA, IgG, and IgM. Estimates of direct heterosis were significant for S. typhimurium count and IgA antibody titre but not significant for E. faecium count, caecal pH, and antibody titres of IgG and IgM. 5. The results showed that the Fayoumi breed could be used in breeding programmes to improve immunity traits against S. typhimurium in chickens.

Mass transfer in beef: effect of crossbreeding and ultrasound application

ABSTRACT: Cuts of muscle (biceps femoris) from three crossbreeds between the Nelore, Angus and Wagyu breeds of cattle (Crossbreed 1 (C1): ½ Angus and ½ Nelore; Crossbreed 2 (C2): ¾ Angus and ¼ Nelore; Crossbreed 3 (C3): ½ Wagyu, ¼ Nelore and ¼ Angus) were characterized by their chemical composition, pH, water activity and lipid oxidation. The cuts were submitted to wet brining in a 5 % NaCl concentration at 5 °C with either static brine (SB) or brine assisted with ultrasound (US). Samples of the treatments were taken after 30, 60, and 120 min of wet brining for later analysis. The experimental data were adjusted using the Peleg and Page models, and the Page template best described the experimental data. The crossbreeding did not affect the water and ash content; however, it significantly affected the levels of lipids and proteins. C3 presented higher fat content than C2, which, in turn, was higher than C1. C1 had higher protein content than C2, which had more protein than C3. When ultrasound was applied, crossbreeding influenced the water content and the water absorption rate during brining, which had the highest values for the highest protein content. The crossbreeding and ultrasound application also affected the NaCl content of the cuts. However, only ultrasound application increased the rate of NaCl absorption during wet brining. The results demonstrate that ultrasound accelerates the mass transfer in wet brining of the cuts of beef, regardless of the crossbreeds studied.

Influence of breeding pig breeding on efficiency production of the industry

The article considers the problems of development of breeding pig breeding in Ukraine as a basis for the functioning of efficient and competitive commodity production. According to the results of the study, with the reform of agricultural production, commodity pig farming suffered significant losses, which had a negative impact on the efficient operation of breeding farms, especially breeders. The main reasons for the intensification of destructive phenomena in the field of breeding pig farming are the unstable level of purchase prices for pig products, low profitability and unprofitable production. It is obvious that the organization of the domestic selection system has a significant impact on reducing the cost and increasing the profitability of pig production, ensuring the quality and competitiveness of breeding (genetic) resources. The results of scientific research show that a significant increase in productivity in pig breeding is achieved through the effect of heterosis in interbreeding, and it is proved that under favorable conditions, the effect of crossbreeding is on average live weight gain of about 10-15% and feed payment 8- 10%. It is proved that to date there has been no clear pattern of a positive trend of change in the yield of piglets per sow in breeding pigs. Analysis of the procedure for receiving funds under the state program for partial reimbursement of the cost of breeding animals purchased for further reproduction shows that in 2017 compensation for breeding pigs and boars of domestic origin ("elite" class) was 20% of the planned due to lack of state budget funds for appropriate measures . In 2018, this amount of compensation was increased to UAH 5,000 per head. It was found that the unit cost of live weight of a breeding animal in 2017 was 2-2.5 times higher than in commercial pig farms. The high cost of production of breeding animals is due to higher feed costs due to components of the diet of mainly foreign production. It is obvious that the difficult financial situation determines the low investment attractiveness of the breeding pig industry for both domestic and foreign investors. Key words: breeding pig breeding, animal productivity, breeding breeders, market dynamics, import of breeding pigs, production cost, state support programs.

The activity of alkaline phosphatase in the blood of purebred and crossbred heifers

Simmental breed of cattle combines dairy and beef productivity. The crossbreeding cows of Simmental breed with Red-and-White Holstein breed of cattle was supposed to obtain animals with high milk productivity, good adaptability to the industrial technology of milk productivity. Red-and-White breed of cows has been bred in Russia as a result of this crossbreeding. It is a relatively young breed of dairy productivity in our country. In order to evaluate the effect of crossbreeding and study the adaptive capabilities obtained by animals, the synthesis of alkaline phosphatase by its activity in blood serum has been studied. The level of activity of the enzyme reflected the intensity and direction of biochemical processes in animals, affecting the state of homeostasis in purebred (Simmental) and crossbred (F1 Simmental×Red-and-White Holstein) heifers and first-calf heifers. It has been found that activity of serum alkaline phosphatase has decreased with age in both purebred and crossbred animals. Crossbreds F1 surpassed purebred heifers in enzyme activity at 1 and 10 months of age, this difference was significant. The activity of the enzyme in first-calf heifers was different from that in the blood of growing heifers, they had it lower. A close and significant correlation has been found between the live weight of growing crossbred heifers and the activity of alkaline phosphatase in the blood serum at 2-, 6- and 12-month age. Crossbred first-calf heifers were significantly higher in milk yield for 90 days of lactation than their Simmental herdmates. The set of data on the activity of alkaline phosphatase in the blood of heifers and lactating cows is of both theoretical and practical value for zootechnical and biological sciences, revealing the regularities of the heterosis effect, deepening knowledge about the age-related biochemistry of crossbred animals and the formation of productive traits.

The Effect of Crossbreeding on Some Economic Traits for Chicks of Lohmann Chicken

The experiment has been conducted at the poultry farm of Al-Qadisyah University, College of Agriculture, Department of Animal Production , for the period 24/11/2018 till 10/4/2019 by using 80 hatching chicks which belong to 20 dams and 5 sires, each sire includes 16 chicks. Four chickens are put with each sire, the first sire( Leghorn) crossbreeding with dams of Lohmann , the remaining sires are local cocks ,with five Lohmann hens. The chicks of each sire divided into two replicates ,each replicate contains 8 chicks , the experiment continues for 42 days of age.
 The experiment aims to study the effect of sire groups on growth traits (weight at hatching , weight at 42 days of age , weight gain and daily weight gain ) Also , the effect of sire on weekly consumption feed , in addition to estimate the heritability for previous traits and the genetic correlations among these traits.
 The results can be summarized as follows :
 
 
 The overall means of weight at hatching , weigh at 42 days of age , weight gain and daily weight gain are 34.572 , 354.898 , 320.327 and 7.627 gm respectively , the sire groups appear significantly (p<05) effect on weight at hatching and weight at 42 days of age and weekly consumption seeds.
 
 
 Sex has significantly (p<05) effect on weight at hatching and weight at 42 days of age.
 
 
 The conversion feed ratio is 3.462 gm consume feed/ gm of meat.
 
 
 The estimated values of heritability for weight at hatching weight at 42 days of age , weight gain and daily weight gain and daily weight gain , are 0.332 , 0.55 , 0.55 and 0.56 respectively.
 
 
 The values of genetic correlation between weight at hatching and weight at 42 days of age and between weight at hatching and weight gain are 0.98 and 0.58 respectively.

The Effect of Crossbreeding on Some Economic Traits for Chicks of Lohmann Chicken

The experiment has been conducted at the poultry farm of Al-Qadisyah University, College of Agriculture, Department of Animal Production , for the period 24/11/2018 till 10/4/2019 by using 80 hatching chicks which belong to 20 dams and 5 sires, each sire includes 16 chicks. Four chickens are put with each sire, the first sire( Leghorn) crossbreeding with dams of Lohmann , the remaining sires are local cocks ,with five Lohmann hens. The chicks of each sire divided into two replicates ,each replicate contains 8 chicks , the experiment continues for 42 days of age. The experiment aims to study the effect of sire groups on growth traits (weight at hatching , weight at 42 days of age , weight gain and daily weight gain ) Also , the effect of sire on weekly consumption feed , in addition to estimate the heritability for previous traits and the genetic correlations among these traits. The results can be summarized as follows : 1- The overall means of weight at hatching , weigh at 42 days of age , weight gain and daily weight gain are 34.572 , 354.898 , 320.327 and 7.627 gm respectively , the sire groups appear significantly (p0.05) effect on weight at hatching and weight at 42 days of age and weekly consumption seeds. 2- Sex has significantly (p0.05) effect on weight at hatching and weight at 42 days of age. 3- The conversion feed ratio is 3.462 gm consume feed/ gm of meat. 4- The estimated values of heritability for weight at hatching weight at 42 days of age , weight gain and daily weight gain and daily weight gain , are 0.332 , 0.55 , 0.55 and 0.56 respectively. The values of genetic correlation between weight at hatching and weight at 42 days of age and between weight at hatching and weight gain are 0.98 and 0.58 respectively.

The Effect of Crossbreeding on Some Economic Traits for Chicks of Lohmann Chicken

The Effect of Crossbreeding on Some Economic Traits for Chicks of Lohmann Chicken

Effects of genotypes and crossbreeding on the quality parameters of dry-cured shoulders from different Iberian genetic pig lines

Iberian pigs are a porcine breed, in which is very important to obtain a genetic line showing a larger prolificacy and performance of valuable parts, without affecting the meat quality. The main objective of this work was to estimate genetic and crossbreeding effects on quality parameters on dry-cured Iberian shoulders from the different genotypes of the Iberian pigs. For that, three Iberian pigs’ varieties (Entrepelado, Retinto and Torbiscal) and their reciprocal crosses were used. Thus, three genetic lines showed the best results: (i) the Retinto genetic line (R×R) showed the results with the highest mean values in MUFA (56.02%) and the lowest in salt content (3.12%), which could have a useful genetic basis for the improvement; (ii) the crossed genetic line between Torbiscal and Entrepelado (T×E) is characterized for a high value of myoglobin (9.05 mg/g) that it is related to some sensory attributes (flavor persistence − 5.82- and juiciness − 6.02-); (iii) the crossed genetic line between Retinto and Entrepelado (R×E) is characterized for a high content of lipids (8.32%), which is related to high scores on some sensory attributes (fat oiliness − 6.64-, juiciness − 6.24- and odour intensity − 6.86-). Therefore, these three genetic lines of Iberian pig based on terms of quality are adequate to produce meat and meat products from the Iberian pigs, outstanding R×R genetic line of Iberian pig.

Crossbreeding effects on growth and efficiency in beef cow-calf systems: evaluation of Angus, Caracu, Hereford and Nelore breed direct, maternal and heterosis effects.

The objective of this study was to determine breed additive and heterosis effects on growth curves, total milk yield (TMY), calf weaning weight (WW), predicted energy intake (EI), and cow efficiency (CE) of purebred and crossbred beef cows raised in Southern Brazil. The data were from 175 purebred and crossbred cows representing eight genetic groups: Angus (A), Hereford (H), Nelore (N), A × H (AH), H × A (HA), A × N (AN), N × A (NA), and Caracu (C) × A (CA). Growth of the cows was modeled using the nonlinear Brody function and machine milking was used to assess TMY. WW was linearly adjusted to 210 d. EI was predicted with an equation in which the independent variables were estimates of parameters of the Brody function and TMY. The ratio of WW to EI estimated CE. Taurine–indicine heterosis effects were significant for all traits, and greater than those for taurine breed crosses. In general, crossbred cows were heavier at maturity, matured earlier, produced more milk, weaned heavier calves, and were predicted to consume more energy. Thus, they were more efficient than purebred cows, despite their greater predicted feed intake. Among the purebreds, A cows matured most rapidly, weighed the least at maturity, produced the most milk, weaned the heaviest calves, were predicted to consume the least energy; and were therefore most efficient among the breeds that were evaluated. These results are useful as inputs to bioeconomic models that can be used to predict productive and economic outcomes from crossbreeding and to facilitate recommendations for beef producers of southern Brazil and other similar subtropical climatic regions.

PREDICTION OF DAILY GAIN, BACKFAT THICKNESS AND FEED CONVERSION RATIO AMONG CROSSBRED TERMINAL SIRES BETWEEN PUREBRED DUROC, PIETRAIN, AND LANDRACE BY CBE 4.0 SOFTWARE

The objective of the study is to compare the practical results with the predicted results by Crossbreeding Effects (CBE) software on pig crossbred based on daily gain, backfat thickness and feed conversion ratio. Another purpose of this study is to predict those three traits among some expected hybridization. This research was conducted on pig farm at Binh Thang Research and Development center from 2013 to 2017. In this study, for each pair of purebred Duroc and Pietrain, Duroc and Landrace, Pietrain and Landrace, twelve hybridizations were analyzed, nine unhybridizations were predicted by CBE software. The results showed that there was no significant difference between the predicted and actual data. With some unhybridization crossbred , the predictions showed high reliability (P<0.05). Based on the predicted data of CBE software , some traits of the crossbred animals would not be improved, therefore, it was not necessary to conduct these hybridizations

関東産河川型オスサクラマスとの交配による千歳川産サクラマス種苗のスモルト化への影響

関東産河川型オスサクラマスとの交配による千歳川産サクラマス種苗のスモルト化への影響

Effect of Crossbreeding on Beef Production of Jersey Herd Using Fleckvieh Sires Maintained on a Pasture-Based Feeding System

Jersey bull calves and steers produce high quality meat; however, the growth rate of Jersey bull calves for veal and beef are low in comparison to other dairy breeds. This could be improved by crossbreeding with beef breeds. In the current study, the veal and beef production of Jersey and Fleckvieh × Jersey (F × J) bull calves and steers were compared. Bull calves were reared intensively for veal up to a carcass weight not exceeding 100 kg, or as steers for beef to 21 months of age. In both veal and steer production systems, the mean birth weight of F × J bull calves was higher (P < 0.001) than Jersey bull calves, i.e. 33.5 ± 1.2 kg vs. 27.9 ± 1.2 kg and (33.4 ± 0.9 kg vs. 26.9 ± 0.9 kg, respectively. The body weight of Jersey and F × J veal calves at 6 months of age differed (P < 0.01) being 163.5 ± 3.9 and 180.6 ± 4.0 kg respectively. This could be attributed to a higher (P < 0.01) average daily gain (ADG) of 0.82 ± 0.02 kg/day for F × J compared to 0.73 ± 0.02 kg/day for Jersey bull calves. Marketing age in the veal production system differed (P < 0.001) with Jersey and F×J bull calves marketed at 7.1 ± 0.1 and 6.3 ± 0.1 months of age, respectively. End live weight at 21 months of age of Jersey and F × J differed (P < 0.01) being 322.6 ± 13.4 and 441.4 ± 14.9 kg respectively. This was due to a higher (P < 0.01) average daily gain in F × J vs. Jersey steers, i.e. 0.64 ± 0.02 and 0.46 ± 0.0 kg/day, respectively. Fleckvieh × Jersey steers had a higher (P < 0.01) carcass weight at 21 months of age being 206.5 ± 8.9 kg vs. 157.9 ± 8.6 kg respectively. These results indicated the potential of improving beef production characteristics of the Jersey cattle through crossbreeding.

Crossbreeding effects on rabbit reproduction from four maternal lines of rabbits

Litter size is essential for an efficient production of rabbit meat. A diallel cross between four maternal lines was carried out and the analysis of the components of litter size has been already done. This paper presents the analysis of litter size traits themselves (total born (TB), number born alive (NBA), number weaned (NW)) and kindling interval (KI), that complete the analysis of the reproductive performance. The 16 genetic groups were distributed in four Spanish farms. The V line was present in all farms in order to be used as reference group. A total of 34 546 parities from 7111 does, were analysed. The crossbreeding parameters were estimated according to Dickerson model. The differences between lines performance were of low magnitude and not significant for litter size traits. The LP line showed the shortest KI followed by H respect to lines A and V. These differences reflected the differences between direct and maternal genetic effects. The differences between the average of all crosses and line V were found to be significant and seemed to be important, being 0.46 for TB, 0.56 for NBA, 0.75 for NW and −2.21 days for KI. The differences between reciprocal crosses for litter size were of low magnitude and non-significant, which indicate that the maternal effects are not important between these lines. In general, the lines did not show significant differences in direct and maternal genetic effects for TB, NBA and NW but there were some significant differences for KI, which ranged from 1.54 to 6.85 days in direct effects and from 0.63 to 3.38 days for maternal effects. A positive and, in some cases, relevant heterosis was found. The largest heterosis was for TB in the HV cross (1.05 rabbits), followed by the AH (0.74 rabbits), AV (0.57 rabbits) and LH (0.55 rabbits) crosses. For NBA, significant heterosis was found in HV (1.11 rabbits) and AV (0.49 rabbits) and for NW in AV (0.90 rabbits), LH (0.70 rabbits) and LV (0.58 rabbits). Favourable and significant heterosis for KI was found in AV and LV crosses, whereas it was unfavourable in AL and in LH. The more recommended crosses were AV and LH, showing the greatest performances on NW, while the cross HV, which shows the greatest performances an NBA, could be highly recommended when cross-fostering is practised to equalise litter sizes after birth, in this situation the lower NW performance observed could be improved.

The Effect of Crossbreeding on Performance of Crossbred Dairy Cows and Indigenous Cattle Genetic Resources in the North Western Amhara, Ethiopia

The Effect of Crossbreeding on Performance of Crossbred Dairy Cows and Indigenous Cattle Genetic Resources in the North Western Amhara, Ethiopia

Effects of crossbreeding and mutations at the αs1-CN gene in Ethiopian and crossbred goats on casein content, and coagulation properties of their milks. A short review

This short review presents the developments in genetic improvement of Ethiopian goat breeds and the impact of the crossbreeding programs on αs1-CN gene (CSN1S1). The influence of newly identified mutations on milk components and technological properties are considered. The indigenous Ethiopian goat breeds are low milk yielders with high percentage of milk organic component and thus with good technological properties. Crossbreeding programs were taken as an option to improve their genetic potential. The main objective of crossbreeding programs in Ethiopia were to increase milk yield and thus, to enhance protein consumption at household level. The success of crossbreeding programs was impaired due to high input requirements, incompatibility of the genotype with the farmers breeding objectives and the production system, owing mainly to less net benefit than expected from the crossbreeding. Evaluation of CSN1S1 gene revealed 36 mutations, which were not previously reported. Four of these mutations were detected in the exon region of CSN1S1: two synonymous (exons 4 and 12), one non-synonymous (exon 10) and a nonsense mutation (exon 15). The non-synonymous mutation was detected only in the indigenous goats and their crosses with exotic Boer goats. It involved amino acid exchange Gln77→Pro77. Goats carrying this mutation have higher αs1-CN, fat and protein content and good coagulation properties with exceptionally high gel strength. The nonsense mutation involved a transversion, at amino acid position Gln140, CAG→TAG giving rise to a premature stop codon. The mutation was found in three crossbred goats between the exotic Toggenburg buck and the local Arsi-Bale does. This mutation was not detected in any of the local goat breeds and therefore, we assume it originates from the exotic parent. The lesson is the need for careful evaluation of the exotic genes for milk quality in bucks chosen for crossbreeding programs, prior to introduction.

Crossbreeding effects on pig growth and carcass traits from two Iberian strains

An experiment of a 2×2 full diallelic cross between two contemporary Iberian pig strains (Retinto: RR, and Torbiscal: TT) was conducted to estimate the crossbreeding effects for growth and carcass traits. Phenotypic records were obtained under intensive management and consisted of two different data sets. The first set comprised growth traits until weaning and was collected at two different farms (6236 and 1208 records, respectively). Specific data included individual piglet weight at birth and at weaning at 28 days and average daily gain from birth to weaning at 28 days (ADG28) for both RR and TT and their reciprocal crosses. The second set comprised growth data from birth to slaughter (~340 days and ~160 kg) and carcass traits from 349 individuals (randomly) sampled at weaning from the first dataset. Data were analyzed through a Bayesian analysis by using a reparameterization of Dickerson’s model that allowed estimation of the posterior distributions of the following crossbreeding effects: average maternal breed effect (gM), average paternal breed effect (gP) and individual heterosis (hI). Results showed that the relative magnitude of crossbreeding effects depends on the trait analyzed. Crosses where Torbiscal strain was used as mother (RT and TT) achieved the greatest performance for all growth traits at weaning, leading to remarkable gM effects. The most outstanding example is the case of ADG28 where the probability of relevance was one. In contrast, TR cross showed the greatest differences from RR cross for all growth at slaughter and carcass traits. These differences were mainly due to hI and gP crossbreeding parameters. In particular, the posterior mean of hI was more noticeable for live weight at slaughter, average daily gain at slaughter and carcass length, while gP was more relevant for hams (kg) and loins (kg) representing from 3% to10% of average performance of traits. Hence, growth traits at weaning did not reveal any notable advantage of the crossbreeding scheme because of the superiority of the Torbiscal strain with respect to its mothering ability and the small hI. However, results from growth and carcass traits at slaughter would support the implementation of a TR crossbred system. It would allow exploitation of both the gP of the Torbiscal strain and the hI between these two Iberian pig strains. Additionally, gP estimates and phenotypic differences between reciprocal crosses might suggest signs of the presence of paternal genetic imprinting in primal cuts traits.