Selection of dairy cattle for growth rate and milk production

The genetic progress in live-weight-for-age (LFA), milk production, and in overall economic value expected as a result of performance and progeny testing of young bulls with respect to milk production and LFA was computed. It was shown that performance testing can contribute considerably to overall progress in economic value, while under certain circumstances progeny testing for LFA can also contribute to genetic progress in overall economic value, but to a lesser degree than performance testing. The relative economic value of LFA and milk production was derived and found to be relatively stable under differing economic conditions.

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Marker-assisted selection of candidate bulls for progeny testing programmes

Animal Science ◽

10.1017/s0003356100005158 ◽

1990 ◽

Vol 51 (1) ◽

pp. 63-74 ◽

Cited By ~ 74

Author(s):

Y. Kashi ◽

E. Hallerman ◽

M. Soller

Keyword(s):

Theoretical Analysis ◽

Genetic Markers ◽

Milk Production ◽

Marker Assisted Selection ◽

Specific Marker ◽

Progeny Testing ◽

Genetic Progress ◽

Potential Benefits ◽

Marker Alleles ◽

Selection Of

ABSTRACTA theoretical analysis of the potential benefits of marker-assisted selection (MAS) of candidate bulls prior to entry into a young sire progeny testing programme was carried out. It is assumed that quantitative trait loci (QTL) affecting milk production have been mapped with respect to known genetic markers, and MAS is based on evaluation of elite sires in order to identify marker alleles in coupling to favourable or unfavourable QTL alleles. Candidate bulls, descendants of the elite sire will then be selected, prior to conventional progeny testing, on the basis of the marker alleles derived from the elite-sire ancestor.The analysis considers recombination between marker and QTL, the difficulty of tracing specific marker alleles from sire to progeny, and the expectation that MAS, in practice, will be implemented in the grandsons, rather than in the sons of elite sires. It is shown that MAS of candidate bulls, based on the use of a single diallelic marker in linkage to a QTL will have only a negligible effect on the rate of genetic progress. Increases of 15 to 20% in the rate of genetic gain, however, can be obtained by the use of single polyallelic markers, and increases of 20 to 30% can be obtained by utilizing haplotypes of diallelic or polyallelic markers.

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Performance testing for beef: inter-relationships among traits in bulls tested from an early age

Animal Science ◽

10.1017/s0003356100029007 ◽

1970 ◽

Vol 12 (3) ◽

pp. 451-456 ◽

Cited By ~ 3

Author(s):

M. B. Willis ◽

T. R. Preston

Keyword(s):

Performance Testing ◽

Live Weight ◽

High Energy ◽

Testing System ◽

Feed Conversion ◽

Complete Diet ◽

Final Weight ◽

Highly Correlated ◽

Weight For Age ◽

Selection Of

SUMMARY1. Performance tests were made on 221 bulls of eight breeds or crosses from 90 days of age (weaning) up to 400 kg live weight. Feeding was in individual pens on a high-energy complete diet.2. Pre-weaning gain was not significantly related to gain on test (r = 0·11) nor was 90-day weight to gain on test (r = 0·26) or feed conversion (r = −0·15). Weight for age at 200 and 300 kg was highly correlated with final weight for age (r = 0·72 and 0·89 respectively) while gain on test and final weight for age had a pooled correlation (across breeds) of r = 0·95. The correlation of feed conversion with gain on test was highly significant in all breeds. The range of values (−0·72 to −0·86) is higher than any previously reported estimates possibly due to an absence of initial weight effects, a reduction in the proportion of feed used for maintainenance and the use of complete diets.3. It is suggested that with this testing system at least 50% of bulls could be culled at 300 kg without affecting selection of the best 20% of all bulls starting the test.

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The performance testing of boars I. Performance testing on Finnish experimental stations and genetic and environmental influences on test results

Agricultural and Food Science ◽

10.23986/afsci.71784 ◽

1971 ◽

Vol 43 (1) ◽

pp. 53-62

Author(s):

Elsi Ettala

Keyword(s):

Growth Rate ◽

Feed Efficiency ◽

Performance Testing ◽

Live Weight ◽

Correction Factors ◽

Test Results ◽

Genetic Quality ◽

Effect Of Age ◽

Selection Of

In 1965 performance testing was initiated in Finland for the selection of boars for A.I. use. In 1965—68 a total of 147 boars were tested on four local testing stations. The following average results were recorded: backfat thickness 21.6 mm (at a live weight of 88 kg), growth rate 699 g/day, feed efficiency 2.69 scand. fu/kg growth and testing score (growth + fat) 99.6. The average testing score for boards selected for A.I. use (43 % of tested) was 99.7. Weakness of the legs was noted in 21 % of the boars. The varying initial weights of the male piglets influenced the growth rate very markedly (P < 0.001), and the effect of the initial age was significant with respect to feed efficiency (P < 0.01). The influence of the weight and age at end of test was highly significant with regard to thickness of fat (P < 0.001). Moreover, the weight at end of test affected the testing score significantly (P < 0.001), but the effect of age was eliminated by use of correction factors. The years as well as the testing stations influenced most of the results in a significant manner. The thickness of fat for the Yorkshire boars was significantly greater (P < 0.01) than for the Landrace boars and the former also had a significantly lower testing score. The effect of the genetic variation, influence of sires within breeds, was highly significant (P < 0.001) for all test results. It has thus proved possible to estimate the genetic quality of the boars. The different influences on the test results were analyzed by least squares procedures.

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Genomic Analysis, Progress and Future Perspectives in Dairy Cattle Selection: A Review

Animals ◽

10.3390/ani11030599 ◽

2021 ◽

Vol 11 (3) ◽

pp. 599

Author(s):

Miguel A. Gutierrez-Reinoso ◽

Pedro M. Aponte ◽

Manuel Garcia-Herreros

Keyword(s):

Dairy Cattle ◽

Production Efficiency ◽

Association Studies ◽

Phenotypic Traits ◽

Progeny Testing ◽

Genome Wide Association Studies ◽

Genetic Progress ◽

Breeding Programs ◽

Increased Risk ◽

Selection Of

Genomics comprises a set of current and valuable technologies implemented as selection tools in dairy cattle commercial breeding programs. The intensive progeny testing for production and reproductive traits based on genomic breeding values (GEBVs) has been crucial to increasing dairy cattle productivity. The knowledge of key genes and haplotypes, including their regulation mechanisms, as markers for productivity traits, may improve the strategies on the present and future for dairy cattle selection. Genome-wide association studies (GWAS) such as quantitative trait loci (QTL), single nucleotide polymorphisms (SNPs), or single-step genomic best linear unbiased prediction (ssGBLUP) methods have already been included in global dairy programs for the estimation of marker-assisted selection-derived effects. The increase in genetic progress based on genomic predicting accuracy has also contributed to the understanding of genetic effects in dairy cattle offspring. However, the crossing within inbred-lines critically increased homozygosis with accumulated negative effects of inbreeding like a decline in reproductive performance. Thus, inaccurate-biased estimations based on empirical-conventional models of dairy production systems face an increased risk of providing suboptimal results derived from errors in the selection of candidates of high genetic merit-based just on low-heritability phenotypic traits. This extends the generation intervals and increases costs due to the significant reduction of genetic gains. The remarkable progress of genomic prediction increases the accurate selection of superior candidates. The scope of the present review is to summarize and discuss the advances and challenges of genomic tools for dairy cattle selection for optimizing breeding programs and controlling negative inbreeding depression effects on productivity and consequently, achieving economic-effective advances in food production efficiency. Particular attention is given to the potential genomic selection-derived results to facilitate precision management on modern dairy farms, including an overview of novel genome editing methodologies as perspectives toward the future.

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THE EFFECTS OF SEX AND AGE OF MALE AT CASTRATION ON GROWTH AND CARCASS QUALITY OF YORKSHIRE SWINE

Canadian Journal of Animal Science ◽

10.4141/cjas61-005 ◽

1961 ◽

Vol 41 (1) ◽

pp. 30-39 ◽

Cited By ~ 27

Author(s):

L. A. Charette

Keyword(s):

Growth Rate ◽

Iodine Number ◽

Feed Efficiency ◽

Carcass Characteristics ◽

Live Weight ◽

Carcass Quality ◽

Selection Of ◽

Effect On Growth

The effects of sex and age of castration of males on growth rate, feed efficiency and carcass characteristics in bacon type swine were measured using 16 pigs each as gilts, entire boars, and boars castrated at birth, 6, 12, 16, and 20 weeks of age. Castration at 20 weeks was too late since some pigs reached 200 pounds live weight before that age. Boars consumed less feed daily than barrows and gilts, were thinner in loin fat, and yielded a higher percentage of shoulder than gilts. The carcasses of boars and gilts were longer, had less fat covering over the shoulder and back, a larger area of loin, and a higher iodine number than those castrated late. Acceptability tests showed that sex or age of castration did not affect the flavour, odour, or tenderness of the meat.Purebred breeders can delay castration for better selection of boars without any serious effect on growth, physical carcass characteristics, and feed requirements. Although the market discriminates against boars, it appears questionable whether castration is necessary when boars are slaughtered at 200 pounds before they reach the age of 150 days.

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Milk productivity of ﬁrst-calf cows depending on the intensity of their breeding

Siberian Herald of Agricultural Science ◽

10.26898/0370-8799-2021-6-9 ◽

2022 ◽

Vol 51 (6) ◽

pp. 77-83

Author(s):

L. L. Petrukhina

Keyword(s):

Growth Rate ◽

Milk Production ◽

Live Weight ◽

Milk Productivity ◽

Statistical Research ◽

Black And White ◽

Irkutsk Region ◽

Significant Difference ◽

On Farm ◽

Analytical Variation

The paper presents the results of studies of milk productivity of black-and-white cows depending on the age of the ﬁrst insemination and live weight at the ﬁrst calving in the conditions of the Irkutsk region. The dynamics of heifer rearing by year, milk productivity of cows in the 1st and 3rd lactations depending on the intensity of their development has been studied. The experiment was conducted on farm materials from the Irkutsk Region using generally accepted zootechnical, analytical, variation and statistical research methods from 2016 to 2020. Live weight of heifers at all ages met the requirements of the elite and elite-record classes. Analysis of the data showed that the growth rate of the animals increased during 5 years (6.0%, 6.8, 2.3 and 4.8% respectively with a signiﬁcant diﬀerence p ≥ 0.90). With the increased intensity of heifer rearing, an increase in milk yield over 305 days of the ﬁrst lactation was observed. The highest milk production was noted in the 1st (5309-5476 kg) and 3rd (5418-5817 kg) lactations in cows with the ﬁrst fruitful insemination at 13-14 months. The lowest 1st and 3rd lactation yields are obtained from cows inseminated at 20 months of age or older. Higher milk production in the ﬁrst and third lactations was obtained from cows with a live weight at ﬁrst calving of 541-550 kg, 551 kg and higher (5197-5164, 5436-5545 kg respectively). Less milk production was obtained from cows with a live weight at ﬁrst calving of up to 500 kg (4567-5122, 4943-5009 kg). The results obtained make it possible to reveal the inﬂuence of the intensity of rearing heifers on the productive qualities of cows.

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Responses of multi-trait selection in open nucleus schemes for dairy cattle breeding

Animal Science ◽

10.1017/s0003356100006322 ◽

1993 ◽

Vol 56 (3) ◽

pp. 293-299 ◽

Cited By ~ 5

Author(s):

T. H. E. Meuwissen ◽

J. A. Woolliams

Keyword(s):

Food Intake ◽

Genetic Correlation ◽

Milk Production ◽

Deterministic Model ◽

Economic Value ◽

Estimation Method ◽

Breeding Value ◽

Progeny Testing ◽

Secondary Traits ◽

Open Nucleus

AbstractResponses of selection for milk production and secondary traits were predicted in open nucleus schemes using a deterministic model. Secondary traits considered were: traits recorded during lactation (e.g. mastitis resistance; calving ease); traits recorded in the nucleus only (e.g. food intake); traits recorded early in life (e.g. growth rate); and traits recorded late in life (e.g. longevity). Also, genotype × environment interactions between nucleus and commercial herds and predictors of merit in juveniles were considered.Extension of the breeding goal to include an uncorrelated secondary trait, which was recorded at each lactation, had the same heritability as milk production (assumed throughout to be 0·25) and half its economic value, increased total economic gain by a factor of 0·12. This increase was only 0·04, if the heritability of the secondary trait was 0·1. The situation for traits of low heritability was not improved by progeny testing of young bulls due to the short optimized generation intervals. Gain increased only by a factor of 0·04, if the economic value was 0·25.Including a secondary trait of heritability 0·25 and a genetic correlation with yield of 0·5 in the index, only increased economic response rates by a factor of 0·04. However, when the genetic correlation was –0·5 the benefits were greater with increases of 0·09, 0·10 and 0·22 for heritabilities of 0·05, 0·10 and 0·25, respectively. Hence, including traits with low heritability but with strong negative correlations with yield, which might apply to fertility and disease resistance, increased rates of gain moderately.If an uncorrelated secondary trait was recorded in the nucleus only, e.g. food intake, and had half the economic value of milk production, total gains increased by a factor of 0·10. Hence, recording of secondary traits can be restricted to the nucleus with only minor loss of gain. The extra economic benefit was greatest from secondary traits measured early in life compared with late in life, e.g. longevity, with benefits increased by factors of 0·24 and 0·06, respectively.Open nucleus schemes are robust in the presence of genotype × environment interactions between nucleus and commercial herds, if the breeding value estimation method accounts for these interactions, juvenile indicator traits of milk production may increase rates of gain by a factor of 0·11, if the heritability of the indicator trait is 0·25 and the correlation with milk production is 0·5.

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Growth and herbage consumption of grazing Merino and Border Leicester lambs reared by their mothers or fostered by ewes of the other breed

Animal Science ◽

10.1017/s0003356100011041 ◽

1972 ◽

Vol 14 (3) ◽

pp. 317-322 ◽

Cited By ~ 27

Author(s):

J. P. Langlands

Keyword(s):

Growth Rate ◽

Food Intake ◽

Milk Production ◽

Live Weight ◽

The Other ◽

Weight Gains ◽

Ad Libitum ◽

Voluntary Food Intake

SUMMARYEight Border Leicester castrated male lambs (wethers) were fostered on to 8 Merino ewes (MB) at birth, and 10 Merino wethers were fostered on to Border Leicester ewes (BM). Two additional groups of 10 wethers consisted of Border Leicester lambs (BB) and Merino lambs (MM) reared by their natural mothers. The lambs and ewes grazed together and growth rate, and milk and herbage consumption of the lambs were recorded.Live-weight gains to weaning at 74 days were 275, 245, 204 and 184 g/day for groups BB, MB, BM and MM respectively. Lambs reared by Border Leicester ewes received more milk and consumed less grass than lambs of similar genotype reared by Merinos, but BM lambs consumed less milk than BB lambs. Merino lambs also consumed less grass than Border Leicester lambs.It was concluded that Merinos grew more slowly than Border Leicester lambs primarily because of their lower voluntary food intake. The lower milk production of Merino ewes was considered to be of secondary significance since if herbage is available ad libitum, lambs with high voluntary intakes will compensate for the lack of milk by consuming more forage.

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INFLUENCE OF FARMING SYSTEMS ON INDICATORS OF BEEF CALVES GROWTH

JOURNAL OF ANIMAL SCIENCE OF BIH ◽

10.7251/jas1502002d ◽

2019 ◽

Vol 1 (2) ◽

Author(s):

J. Ducháček ◽

R. Toušová ◽

L. Stádník ◽

Z. Biniová ◽

M. Ptáček ◽

...

Keyword(s):

Average Daily Gain ◽

Live Weight ◽

Farming Systems ◽

Farming System ◽

Genetic Progress ◽

Ecological Farming ◽

Model Equations ◽

Daily Gain ◽

Selection Of ◽

Growth Ability

The aim of this study was to evaluate growth ability of Charolais calves in different systems of farming. The observations were performed in period of 8 years (2007 - 2014) in one herd, which was transiting from conventional to ecological farming system. Period from 2007 to 2010 was of conventional character, 2010 to 2012 transition phase, and from 2012 to 2014 ecological phase. This transfer is directly linked to changes in cow´s welfare and nutrition. Growth ability (live weight at birth, 120, and 210 days of age, average daily gain from birth to 120, from birth to 210, and from 120 to 210 days of age) of 518 Charolais calves was measured. Statistical analyses were performed using SAS 9.3 software, GLM procedure. The model equations contend effect of sex, number of parity, month of calves birth and type of farming system. Difference in birth weight of calves between farming systems was small and insignificant. This fact may be due to breeding system focused on easy calving. Increase of values measured in different age and average daily gains were statistical significant (P < 0.05) between conventional and ecological farming. The increase of parameters of weight and average daily gain could be largely connected with genetic progress in Charolais population in Czech Republic and following good selection of bulls to insemination and natural breeding. Nevertheless, the transition from conventional to ecological farming system did not affected growth ability of beef cattle negatively and, in contrary, results of growth improved farm economy.

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Effects of ewe live weight and age on reproductive performance, lamb growth, and survival in Central Anatolian Merino sheep

Archives Animal Breeding ◽

10.5194/aab-58-451-2015 ◽

2015 ◽

Vol 58 (2) ◽

pp. 451-459 ◽

Cited By ~ 10

Author(s):

A. H. Aktaş ◽

Ş. Dursun ◽

Ş. Doğan ◽

Z. Kiyma ◽

U. Demirci ◽

...

Keyword(s):

Growth Rate ◽

Reproductive Performance ◽

Birth Rate ◽

Live Weight ◽

Fertility Rate ◽

Multiple Birth ◽

Growth And Survival ◽

Merino Sheep ◽

Lamb Growth ◽

Selection Of

Abstract. The aim of this study was to evaluate the effects of premating ewe weight and age on ewe reproductive performance, lamb growth and survival in Central Anatolian Merino (CAM) sheep. The trial included 4935 ewes and 5548 lambs from 23 breeder flocks in Eskişehir Province. The live weights (LWs) and ages of the ewes were recorded 1 week before the mating season. The number of lambs born, fertility rate, multiple birth rate (MBR), and lamb survival rate (SR) at days 75 and 120 were determined. The effects of the LW and age of the ewe were found to be important for the reproductive performance of ewes and for the lamb's growth rate (P < 0.05–0.001). Ewe MBRs and the birth weight (BW) and LW of the lambs at days 75 and 120 increased proportionally with the increase in LW in ewes prior to mating. The fertility rate and MBR were lower (P < 0.05–0.001) in 1.5-year-old ewes than in older ewes. However, lambs' SR at days 75 and 120 were not affected by the premating LW and age of the ewe. In summary, a better reproductive performance and lamb growth rate in CAM flocks may be achieved by the selection of breeding ewes from ewes weighing more than 60 kg.

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