Effects of genetic selection for milk production on energy status and reproductive efficiency of high- and average-producing dairy cows

Reproduction and milk production are the principal factors that are influencing dairy farm profitability. The dairy industry in Iran has changed dramatically in the last decade. The shift toward more productive cows and larger herds in Iran is associated with a decrease reproductive efficiency (Heravi Moussavi et al., 2004). Increased knowledge about the principal causes of reduced fertility is essential. The root cause of the declining fertility is probably a combination of a variety of physiological and management factors that have an additive effect on reproductive efficiency. Dairy cattle are inseminated and pregnancy is established while dairy cows are lactating. Based on the analyses of large datasets, there is clearly an antagonistic relationship between milk production and reproduction in dairy cattle (Lucy, 2001). It was shown that the hazard ratio for cumulative first 60-day milk yield and conception in high producer cows was 8 percent less than the others and also high milk yield was a risk factor for several reproductive disorders (Grohn and Rajala-Schultz, 2000). The objective of this study was to evaluate the effect of first 60-day cumulative milk yield on days open in Iranian Holstein dairy cows.

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Consequences of genetic selection for increased milk production in European seasonal pasture based systems of milk production

Livestock Science ◽

10.1016/j.livprodsci.2005.06.011 ◽

2006 ◽

Vol 99 (2-3) ◽

pp. 141-158 ◽

Cited By ~ 65

Author(s):

P. Dillon ◽

D.P. Berry ◽

R.D. Evans ◽

F. Buckley ◽

B. Horan

Keyword(s):

Milk Production ◽

Genetic Selection ◽

Selection For

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A review of bovine growth hormone

Canadian Journal of Animal Science ◽

10.4141/cjas94-027 ◽

1994 ◽

Vol 74 (2) ◽

pp. 167-201 ◽

Cited By ~ 77

Author(s):

Jeanne L. Burton ◽

Brian W. McBride ◽

Elliot Block ◽

David R. Glimm ◽

John J. Kennelly

Keyword(s):

Growth Hormone ◽

Mammary Gland ◽

Growth Factor ◽

Dairy Cows ◽

Milk Production ◽

Reproductive Efficiency ◽

Bovine Growth Hormone ◽

Insulin Like Growth Factor ◽

Factor I ◽

Exogenous Growth

Unprecedented numbers of technical papers, abstracts, and short communications have been published in the past decade regarding the effects of exogenous bovine growth hormone on milk production, health, and reproductive efficiency of treated dairy cows. In well-managed dairy herds, exogenous growth hormone increases milk production without altering normal variability in milk composition. This has held true regardless of dairy breed tested, geographical location studied, or feeding management system used. Also consistent across studies is the rapidity of the galactopoietic effect of administered bovine growth hormone, which arises from altered partitioning and use of post-absorptive nutrients and increased synthetic capacity of the mammary gland. Growth hormone and its associated peptide, insulin-like growth factor-I, are now known to provide chronic lipolytic, diabetogenic, and gluconeogenic signals to target tissues culminating in increased mammary gland availability of glucose and nonesterified fatty acids. Together with yet ill-defined effects on mammary secretory tissue, this homeorhetic control of metabolism elicited by exogenous growth hormone is so efficient that treated cows are not more susceptible to metabolic disorders than untreated cows. However, some studies have reported an increased frequency of mastitis in groups of treated cows. This has been attributed mainly to increased milk volume in the mammary glands of treated cows and no convincing data are available that show decreased mammary gland immunity as a result of growth hormone treatments. On the contrary, an expanding body of evidence implicates growth hormone as a key neuroendocrine factor that is required for immunological competence. Trends of decreased reproductive efficiency in cows treated with growth hormone have also been reported, but available data imply that this is probably an indirect effect via prolonged negative energy balance in cows treated in early lactation rather than a direct negative effect on estrous cycling via altered reproductive hormone profiles. The objectives of the present review are to bring into focus and summarize pertinent biological discoveries regarding the treatment of dairy cows with recombinant bovine growth hormone, and to explore areas where additional growth hormone research is needed or warranted. Key words: Growth hormone, somatotropin, dairy cows, insulin-like growth factor-I

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Physiological attributes as possible selection criteria for milk production 1. Study of metabolites in Friesian calves of high or low genetic merit

Animal Science ◽

10.1017/s0003356100024168 ◽

1980 ◽

Vol 30 (3) ◽

pp. 327-340 ◽

Cited By ~ 39

Author(s):

N. Tilakaratne ◽

J. C. Alliston ◽

W. R. Carr ◽

R. B. Land ◽

T. J. Osmond

Keyword(s):

Fatty Acids ◽

Free Fatty Acids ◽

Milk Production ◽

Selection Criteria ◽

Plasma Concentrations ◽

Genetic Selection ◽

Sodium Propionate ◽

Genetic Merit ◽

Selection For ◽

Blood Characteristics

ABSTRACTThe use of variation in metabolism to predict genetic merit for milk production was studied using 42 Friesian calves: 11 ♀♀, 10 ♂♂ were the offspring of four bulls with high (H), and 11 ♀♀, 10 ♂♂ of four with low (L) improved contemporary comparison (ICC) values (mean = + 402 kg and − 276 kg respectively). The animals were 14 or 15 weeks of age at the start of the study and treated similarly throughout.Blood samples were collected: I—in relation to feeding; II—at set intervals; III—during a 44-h fast; and IV—following the sudden introduction of an energy metabolite (sodium propionate), and then refeeding. Plasma concentrations of β-hydroxybutyrate, glucose, urea, free fatty acids, total proteins and albumin were measured in all samples.Blood characteristics apparently differed among animals, particularly protein and urea (repeatability 0·74 and 0·62 respectively).The progeny of high ICC bulls had lower levels of urea during fasting (H = 4·70, L = 5·62P< 0·05) but higher levels of free fatty acids (H = 578, L = 492 μ equivalents/l;P< 0·05). There was a small difference in total protein (H = 69·7, L = 66·8 g/l,P< 0·05) but the other metabolites showed no significant ICC group difference.In general, sex of the animal did not influence the metabolites.Results suggest that calves with different potentials for milk production vary in aspects of energy and nitrogen metabolism; the possibility of using these as criteria for genetic selection for milk production is discussed.

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Options to reduce vulnerability to metabolic stress by genetic selection

BSAP Occasional Publication ◽

10.1017/s1463981500043132 ◽

1999 ◽

Vol 24 ◽

pp. 119-127 ◽

Cited By ~ 2

Author(s):

J. E. Pryce ◽

P. Løvendahl

Keyword(s):

Milk Production ◽

Genetic Selection ◽

Metabolic Stress ◽

Live Weight ◽

Genetic Merit ◽

Condition Score ◽

Breeding Programmes ◽

Selection For ◽

Breeding Goals ◽

High Yields

AbstractGenetic selection for milk production has been very successful. However to achieve high yields, the metabolic load on dairy cows is believed to be substantial. If the size of this load is large enough then the animal may become ‘metabolically stressed’. Signs of this may include some sort of distortion of normal physiological function. There is evidence from both population studies and research herds to suggest that intense selection for milk yield has led to a deterioration in some aspects of health and fertility. Genetic correlation estimates between production and measures of fertility are unfavourable. As an example, calving intervals of high merit animals from Langhill are on average 12 days longer than those of average genetic merit, which is mostly due to a delay in days to first heat. It is suggested that some aspects of health and fertility problems in high genetic merit animals are a consequence, in part, of so-called metabolic stress. Future breeding goals should be broadened to include a broad spectrum of traits related to efficient milk production, in addition to either health and fertility traits themselves, or traits believed to be precursors of them, such as those related to metabolic stress. The complexity and subjectivity of metabolic stress and its components makes it very difficult to include in future breeding goals. However, traits related to energy balance, such as some measures of condition score, dry-matter intake and live weight may be useful in breeding programmes where one of the goals is to alleviate metabolic stress.

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368 CONCEPTION RATE AT FIRST ARTIFICIAL INSEMINATION WITH SEXED SEMEN OR CONVENTIONAL SEMEN IN CROSSBRED DAIRY COWS

Reproduction Fertility and Development ◽

10.1071/rdv22n1ab368 ◽

2010 ◽

Vol 22 (1) ◽

pp. 340

Author(s):

B. T. Gerhardt ◽

L. D. P. Sinedino ◽

A. P. Dourado ◽

P. A. M. Alves ◽

L. A. G. Nogueira

Keyword(s):

Dairy Cows ◽

Milk Production ◽

Genetic Selection ◽

Conception Rate ◽

Control Group ◽

Chi Square ◽

Fertility Reduction ◽

Estrus Detection ◽

Sexed Semen ◽

Experimental Group

The use of sexed semen in dairy cattle almost eliminates the birth of unwanted male calves and can lead to increased milk production by means of genetic selection exerted on the females. However, AI with sexed semen still presents several obstacles to overcome. Holstein-Zebu cows are responsible for 80% of the milk produced in Brazil. These crossbred animals are used extensively throughout the country because their physiologic and morphologic characteristics are compatible with milk production in the tropics which results in an economic performance advantage. The objective of this study is to evaluate the conception rates with sexed semen, comparing it to the use of non-sorted semen in crossbred dairy cows. In addition, two insemination times had been studied to determine the best timing for AI with the sexed semen. Both studies were carried out in the Experimental Station Seropedica of Pesagro-RJ, located in the state of Rio de Janeiro, Brazil. The experiment was done in 2008/2009 (January to April). In the first Trial 56 Holstein-Zebu females, composed of 1/2 to 7/8 Holstein genetics, were inseminated 12 h after estrus detection with non-sorted semen (control group n = 29, 14 heifers and 15 cows) or with sexed semen (experimental group n = 27, 13 heifers and 14 cows). The semen utilized was from the same bull and thawing was performed intravaginally. In the second trial, 55 females were inseminated only with sexed semen from the same bull, with thawing in water at 35°C, at two different times: 12 h after estrus observation (control group n = 27, 12 heifers, 4 primiparous, and 11 multiparous) and 15 h after estrus observation (experimental group n = 28, 12 heifers, 5 primiparous, and 11 multiparous). The pregnancy diagnoses were done by rectal palpation and transrectal CAT scan at Day 45. Statistical analyses had been done using Chi-square. The conception rate in the first trial was of 17.2% (5/29) for sexed semen and 53.8% (14/26) for non-sorted semen (P < 0.05). In the second trial, the conception rate was of 37.0% (10/27) for insemination with sexed semen, 12 h after estrus observation and 50.0% (14/28) for the females inseminated 15 h after estrus observation (P > 0.05). It is possible that one of the causes of fertility reduction with sexed semen is that sexed-sperm remain viable for a shorter time after the insemination. Inseminations with sexed semen done 15 h after estrus detection, which can be more synchronized with the time of ovulation, and when accompanied by closely controlling the thawing process, show results similar to those obtained with conventional semen.

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The challenge of genetic selection for heat tolerance: the dairy cattle example

Advances in Animal Biosciences ◽

10.1017/s2040470016000169 ◽

2016 ◽

Vol 7 (2) ◽

pp. 218-222 ◽

Cited By ~ 3

Author(s):

M. J. Carabaño

Keyword(s):

Milk Production ◽

Heat Tolerance ◽

Genetic Selection ◽

High Heat ◽

Temperate Climate ◽

Environment Interaction ◽

Heat Tolerant ◽

Selection For ◽

Heat Loads ◽

Selection Of

Exposure of livestock to high heat loads negatively affects animal’s productivity. Genetic selection for heat tolerance using quantitative approaches has been developed by making use of the milk recording information merged with the meteorological information in the test date. The main conclusions of the studies following this approach have been that there is genetic variability in the response to heat stress (HS), that a genotype by environment interaction between thermal comfort and HS conditions exists and that there is a genetic antagonism between HS tolerance and high milk production. This approach has the advantage of adding no extra costs to the existing milk recording schemes, but it has some disadvantages. Current milk recording information does not seem to fully capture the productive response to high heat loads. Moreover, the antagonism between heat tolerance and high milk production may offset the benefits of selection for this trait if heat-tolerant animals are less productive. The use of new tools from phenomics, genomics and transcriptomics can help in achieving an accurate selection of heat-tolerant animals without damaging progress in milk production. New phenotypes for this selection are measure of body temperature and respiration rates together with measures of indicators of heat tolerance in milk, through the use of mid IR spectroscopy. The use of commercial DNA chips to perform genome wide association studies or comparison of whole genome DNA sequence of animals of heat adapted and temperate climate breeds could also provide useful genomic information. Finally, RNA sequencing together with the recent discovery of the possibility to use the milk transcriptome instead of tissue biopsies could help to discover differentially expressed genes under HS and thermoneutrality. The existence of powerful tools to achieve better phenotypes to identify tolerantv. susceptible animals and to gain insights about the genetic mechanisms underlying HS response to be able to disentangle the genetic puzzle of heat tolerance may make possible the selection of heat-tolerant and still productive animals.

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Once-daily milking during a feed deficit decreases milk production but improves energy status in early lactating grazing dairy cows

Journal of Dairy Science ◽

10.3168/jds.2012-6167 ◽

2013 ◽

Vol 96 (10) ◽

pp. 6274-6284 ◽

Cited By ~ 15

Author(s):

J.K. Kay ◽

C.V.C. Phyn ◽

A.G. Rius ◽

S.R. Morgan ◽

T.M. Grala ◽

...

Keyword(s):

Dairy Cows ◽

Milk Production ◽

Energy Status ◽

Once Daily ◽

Grazing Dairy Cows

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Molecular Markers for Metabolic Adaptation in Dairy Cows: SNAI2 Gene Variations

Asian Journal of Dairy and Food Research ◽

10.18805/ajdfr.dr-1763 ◽

2021 ◽

Author(s):

S.V. Vasudhar Bhat ◽

M. Shynu ◽

P.D. Divya ◽

Akshatha G. Desai ◽

G.H. Akhil

Keyword(s):

Cluster Analysis ◽

Molecular Markers ◽

Dairy Cows ◽

Promoter Region ◽

Genetic Selection ◽

Metabolic Adaptation ◽

Exonic Region ◽

Selection For ◽

Pregnant State ◽

Concentration Methods

Background: Healthy transition from non-lactating pregnant state to non-pregnant lactating state is an important in the profitability of dairying. Though feeding and managemental practices play an important role in the adaptation to transition, animals kept on similar feeding and management exhibit differences in adaptation indicating an underlying genetic cause. In the present study, the sequence of gene SNAI2, which is considered to have an effect on metabolic adaptability has been compared among animals with apparently varying adaptability, as indicated by their β-hydroxy butyric acid (BHBA) concentration. Methods: During the period from August 2018 to May 2019, blood was collected and serum was separated from 30 pregnant cross bred (belonging to Sunandini genetic group of cross bred cattle of Kerala) dairy cows at fortnightly intervals from four weeks before the predicted day of parturition until four weeks after parturition. Concentration of BHBA was determined. Based on BHBA concentration the animals were sorted into two groups (High BHBA and low BHBA) using cluster analysis. Blood was collected, DNA extracted and SNAI2 gene amplified using custom synthesised primers. Amplicons from representative animals of each group were sequenced. The sequences obtained were aligned and compared using clustal-ω. Result: The comparison of the sequence of SNAI2 gene amongst the animals having high BHBA and those with low BHBA revealed two variations between the groups, one at promoter region, 61 bp upstream to the gene and other was at exonic region at 1560 bp. In silico structural analysis revealed difference in protein structure. The changes observed in the gene SNAI2 between the sets of animals grouped based on BHBA has to be studied on a larger population to ascertain the suitability of them being used as markers of genetic selection for metabolic adaptability, which in turn can increase the profitability of dairying.

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