Calf Genotype Research Articles

Influence of calf genotype on dam lactation and calf growth in farmed red deer (Cervus elaphus)

Multiparous red deer (Cervus elaphus scoticus) hinds (n=17) were either mated to a red deer stag or artificially inseminated with semen from a wapiti bull (C.e. nelsoni) to produce red deer or F1 crossbred (C.e. scoticus × C.e. nelsoni) calves to test the hypotheses that (1) red deer hinds rearing crossbred calves will produce significantly more milk to support calf growth than hinds rearing red deer calves, and (2) hind live weight and body condition may suffer as a result. Hinds and calves were grazed on ryegrass and white clover pastures and supplemented with pasture silage and barley grain when pasture supply was inadequate. Calves were left with their mothers until 9–10 months of age when lactation had terminated naturally. Mean body condition score (BCS) loss was greater in hinds rearing F1 calves than in hinds rearing red calves in the period from late gestation to mid-lactation (September–March, P<0.05). F1 calves grew significantly faster than red deer calves and were heavier at all ages. From February onwards there was a consistent decline in milk intake, and by the latest measurement (22 July) milk production was negligible, and most hinds had ceased lactating. Milk intake by the F1 calves was significantly greater until day 114, after which the measured milk intake was not significantly different. Pasture intake of the F1 calves was significantly greater at day 114 but not at other times (P<0.05). The average hind pasture intake was also not significantly affected by calf genotype when adjusted for post calving hind live weight. The results support the hypothesis that a red deer hind rearing an F1 calf produces significantly more milk than a hind rearing a red deer calf, suggesting that the growth of a red deer calf is limited by its milk demand rather than milk supply by the hind. The study also supported the second hypothesis. Hinds rearing F1 calves exhibited greater losses of body condition score relative to the hinds rearing red deer calves, indicating that the hinds rearing F1 calves were in a greater negative energy balance that hinds rearing red deer calves. This highlights the additional energetic demands on a hind from feeding an F1 calf and in a farmed context the need to ensure that adequate nutrition is provided.

135 BREEDING VALUES CONCORDANCE BETWEEN EMBRYOS AND CORRESPONDING CALVES

Genomic tools are now available for most livestock species and are used routinely for genomic selection in cattle. Recently, biopsies of pre-implantation-stage embryos were genotyped for multiple markers. This strategy provides the opportunity to estimate breeding values for traits of particular interest and the presence of genetic abnormalities, thus allowing selection of embryos before transfer (Le Bourhis et al. 2011 Reprod. Fertil. Dev. 23, 197 abst). The present work aimed to compare the genotype and the breeding values from biopsied bovine embryos with the corresponding calves. Bovine embryos were obtained after superovulation (8 cows) and flushing at Day 6 or 7. A total of 11 embryos (1 or 2 Grade 1 embryos per flush per cow) were washed and biopsied using a microblade. Biopsies of 5 to 10 cells were transferred individually as dry samples in tubes and frozen before whole genome amplification (WGA). The genomic DNA of each biopsy was amplified using a WGA kit according to the manufacturer's instructions (WGA; QIAGEN REPLI-g® Mini Kit, Qiagen, Valencia, CA, USA). Biopsied embryos were transferred either frozen or fresh to synchronized recipients. At birth a blood sample was taken from the calf for subsequent genotyping. Genotyping was done using the Illumina BovineSNP50TM beadchip. Only embryos with call rate (CR) higher than 80% were selected for breeding values comparisons. Because of allele dropout, heterozygous markers are turned into homozygous makers artificially. Only markers that were still heterozygous in genotypes of an embryo were selected and error rates were calculated with the same markers from the corresponding calf. Imputation was done using Beagle and taking into account the 50 k genotyping results of the parents. Breeding values (milk production and morphological traits) were calculated and compared with those of the 7 corresponding calves. From 11 embryos analysed, only 1 (9%) gave a CR lower than 80% and a higher percentage error with calf genotype (Table 1). These results indicate that, using embryonic DNA after WGA, genotyping errors between embryo and calf are low and correlated with the CR of embryos. For embryos with CR higher than 84, the concordance of genomic values between embryo and calf is very high. More embryo–calf pairs are needed to assess the reliability of this method and to validate the breeding value at the embryo stage. This new technique offers new possibilities in managing breeding schemes by selecting the embryos before transfer. Table 1.Embryo call rate (CR) and genotyping and breeding value concordances between embryos and calves

Evaluation of parentage testing in the Czech population of Holsteincattle

A set of 233 Holstein calves, their 233 dams and 44 sires from 4 large-sized herds was genotyped for 10 microsatellites recommended by ISAG for paternity/parentage testing. Heterozygosity of microsatellites ranged from 0.607 (SPS115) to 0.835 (TGLA227), and PIC from 0.575 (SPS115) to 0.816 (TGLA227) confirming a high polymorphism of each analysed locus. Their combined exclusion probability reached 0.999, which made them suitable and sufficiently accurate for parentage testing. A conflict between putative parents and calf in at least 2 markers with combined exclusion probability &amp;gt; 0.9 was required to reject parentage. The pedigree was considered incorrect in 25 (10.73%) out of the evaluated progeny/parent trios, of which in 10 samples the genotype of both parents did not match their offspring, and in 2 samples the putative dam was in conflict with the calf genotype. This result shows that the interchange of calves on farms with large-sized herds plays the role as important as the errors in sire identification, or recording mistakes. &amp;nbsp;

Época de nascimento, genótipo e sexo de terneiros cruzas taurinos e zebuínos sobre o peso ao nascer, à desmama e eficiência individual de primíparas Hereford

O objetivo deste trabalho foi avaliar o efeito da época de nascimento, genótipo e sexo do terneiro sobre a eficiência individual das vacas à desmama (relação percentual entre o peso do terneiro à desmama e o peso da vaca), peso ao nascer e peso à desmama dos terneiros. Foram utilizadas 48 vacas da raça Hereford (Bos taurus), com idade de três anos, manejadas sobre campo natural, 16 inseminadas com um touro da raça Red Angus (Bos taurus) e 32 com Nelore (Bos indicus). Os fatores estudados foram genótipo do terneiro (GENOT) - Bos taurus x Bos taurus e Bos taurus x Bos indicus, época de nascimento (EPOCN) subdividida em três períodos - 1S (setembro), 2O (outubro) e 3N (novembro) e sexo do terneiro (SEXO). A produção de leite (PL) foi incluída como co-variável. Foram realizadas dez medidas de produção de leite pelo método indireto pesagem - mamada - pesagem e onze medidas de peso para vacas e terneiros, em intervalos de 21 dias. Os fatores que influenciaram significativamente o PN foram GENOT e SEXO (P&lt;0,05). O P205 sofreu influência significativa da EPOCN, SEXO e PL (P&lt;0,05). A EI foi influenciada significativamente pela EPOCN, SEXO e PL até 147 dias (P&lt;0,05). Concluiu-se que genótipo e sexo dos terneiros influenciam o peso ao nascer. O peso à desmama e a eficiência das vacas são influenciados pelo sexo e época de nascimento, mas não pelo genótipo dos terneiros.

Cryptosporidium andersoni from a Danish cattle herd: identification and preliminary characterisation

In November 1997, Cryptosporidium andersoni, for the first time, was isolated from a Danish heifer. The isolate was characterised morphologically, molecularly, and furthermore inoculated into mice and one calf. Data on the distribution of cryptosporidia in the herd of origin were obtained at two separate visits in December 1997 and April 1998. C. andersoni was detected in 27 (19.0%) of 142 cattle examined at the first visit, whereas C. parvum was found in six (4.2%). At the following visit 42 (28.0%) of 150 cattle excreted C. andersoni, while 25 (16.7%) were positive for C. parvum. Oocysts of the Danish C. andersoni isolate were ovoid, 7.3 (6.5–8.0)×5.7 (5.0–7.0) μm 2 ( n=25), with smooth, colourless, single layer oocyst wall and distinct oocyst residuum. The length to width ratio was 1.27 (1.14–1.40, n=25). The identification was verified by sequencing of a 246 bp fragment of the rDNA, which was identical to Cryptosporidium muris, the calf genotype (AF093496). The Danish C. andersoni isolate was not transmissible to mice, whereas oocysts were detected in the faeces of one experimentally infected calf from 25 days post-infection (DPI) and shed intermittently at low numbers until 165 DPI, the day of euthanasia. No macroscopic or microscopic changes that could be attributed to infection with C. andersoni were seen in the gastro-intestinal tract of the experimentally infected calf following necropsy and histological examination. This is to our knowledge the first report of C. andersoni in Scandinavia.

Produção de Leite em Primíparas de Bovinos Hereford e Desenvolvimento Ponderal de Terneiros Cruzas Taurinos e Zebuínos

O objetivo deste trabalho foi avaliar a produção de leite de vacas de corte primíparas e o desenvolvimento ponderal dos terneiros de dois genótipos entre o nascimento e o desmame. Foram utilizadas 48 novilhas da raça Hereford (Bos taurus), com idade de três anos, manejadas sobre campo natural. As raças paternas utilizadas foram Red Angus (Bos taurus) e Nelore (Bos indicus), em 16 e 32 vacas respectivamente. Os fatores estudados foram genótipo do terneiro (GENOT) -- Bos taurus x Bos taurus e Bos taurus x Bos indicus, época de nascimento (EPOCN) distribuída em três períodos -- 1S (setembro), 2O (outubro) e 3N (novembro) e sexo do terneiro (SEXO). Foram realizadas dez medidas de produção de leite pelo método indireto pesagem - mamada - pesagem e onze medidas de peso para vacas e terneiros, em intervalos de 21 dias. A média diária geral de produção de leite foi de 4,80 ± 0,09 kg. Não foram verificadas diferenças significativas na produção de leite em relação aos fatores estudados. O ganho de peso dos terneiros foi influenciado significativamente pela EPOCN, mas não pelo GENOT e SEXO. Concluiu-se que a produção de leite de vacas de corte primíparas, manejadas em campo natural, não foi influenciada pelo GENOT, EPOCN e SEXO dos terneiros. O desenvolvimento ponderal dos terneiros sofreu influência apenas da EPOCN.

Influence of Both Endophyte Infestation in Fescue Pastures and Calf Genotype on Subsequent Feedlot Performance of Steers

Three experiments were conducted to determine the influence of both the concentration of endophytic fungus infestation in tall fescue pastures and calf genotype on the subsequent health and performance of steers in the feedlot. In Exp. 1 and 2, Angus steers grazed fescue pastures in Georgia containing low, moderate, or high endophyte infestations for 182 d (Exp. 1) or 78 d (Exp. 2) with 12 steers per treatment. Steers were transported 1,600km to Texas in October (Exp. 1) and July (Exp. 2), were fed a 93% concentrate diet during the finishing period, and were harvested at an estimated backfat thickness of 12mm. In both trials, DMI over the entire feeding period and carcass characteristics were not affected (P>0.05) by endophyte infestation. In both trials, pasture ADG decreased, and feedlot ADG and gain to feed ratio increased as the previous pasture endophyte infestation increased (P<0.05). Serum cholesterol concentrations tended (P<0.10) to decrease with increasing endophyte infestation during the first 14 d in the feedlot. In Exp. 3, Angus and Brahman × British crossbred steers grazed fescue pastures in Georgia containing low, moderate, or high endophyte in each of 2yr. Six steers of each breed group were on each treatment each year. Steers were transported to Texas in late August of each year, were fed a 93% concentrate finishing diet, and were harvested at an estimated individual backfat thickness of 12mm. As endophyte infestation increased, serum urea N concentrations and gain to feed ratios increased (P<0.05), whereas pasture ADG, initial BW, transit shrink, serum cholesterol concentrations, final BW, and carcass weights decreased (P<0.05) in Angus steers, but not in Brahman-cross steers. In these studies, the adverse effects of high endophyte infestations in fescue pastures appeared to carry over to the feedlot for ca. 14 d. However, steers from highly infested pastures can compensate for poor pasture performance with improved performance in the feedlot when no adverse health effects occur. Any impact of the endophyte seems to be similar in Brahman-cross and Angus steers.

Genotype by environment interactions in winter survival in red deer

1. The extent to which environmental heterogeneity interacts with genetic hetero geneity to affect individual fitness within populations has the potential to affect the dynamics of natural populations and the amount of genetic variation maintained in natural populations, yet is a relatively poorly investigated topic in either ecology or evolutionary biology. 2. Many individual‐based studies are precluded from such investigations by the practical problems of measuring heritability of traits affecting fitness and the difficulties of experimental manipulation of the study population. One way of demonstrating how commonly genotype by environmental interactions affect fitness, though not their overall importance in determining fitness, is to investigate fitness in a population subdivided by genotype at one or more marker loci. 3. We analyse data on calf winter survival from a population of red deer from the Isle of Rum, Scotland. Data on individual survival, environmental fluctuations and genotype at 13 loci were collected from 1982 to 1994. 4. We found associations between survival over the first winter of life and calf genotype at two out of three allozyme loci and five out of 10 microsatellite loci. All of the results remained significant under randomization tests. Other genotypes that initially appeared to have an association with survival were rejected when bootstrapped, usually due to insufficient data or anomalies in the data. 5. Our results suggest that associations between fitness and genotype are common. Five out of the seven associations found involved interactions with environmental variables. Four of these showed density‐dependent selection with different genotypes showing high survival at high population size compared to low population size and one interacted with autumn rainfall. In a sixth case, genotype interacted with sex.

Sire breed of calf influences peripartum endocrine profiles and postpartum anestrus in Brahman cows

The literature indicates that sire breed of calf influences beef calf performance. However, there is little information concerning sire breed of calf effects on reproduction in beef cows. In this experiment, Angus (A), Brahman (B), or Tuli (T) bulls were bred to 136 Brahman (B) cows to examine sire breed of calf influence on peripartum hormone profiles and the length of postpartum anestrus. Cows were bled from 7 d prepartum to 28 d postpartum to determine peripartum hormone concentrations. Cows carrying AB calves had greater (P < 0.05) prepartum estradiol-17β concentrations than did cows carrying BB and TB calves. Prepartum and postpartum progesterone concentrations did not differ between cows with AB, BB, and TB calves. Cows with TB calves had lower (P < 0.01) 13,14-dihydro-15-keto-prostaglandin F 2α (PGFM) concentrations than did cows with AB and BB calves during the early postpartum period. Adjusting for birth weight removed the sire breed of calf effect on postpartum PGFM concentrations, but not prepartum estradiol-17β. Postpartum anestrus was shorter (P < 0.05) for cows nursing BB calves (84 ± 6 d) than for cows nursing AB (101 ± 6 d) or TB calves (110 ± 7 d). Adjustment for estradiol or PGFM concentrations did not reduce sire breed of calf effects on the length of postpartum anestrus. Further work is needed to determine how calf genotype may modulate the postpartum reproductive function of the dam.

Influence of calf genotype on colostral immunoglobulins in Bos taurus and Bos indicus cows and serum immunoglobulins in their calves.

Purebred Bos indicus calves are documented to have lower survival rates than Bos taurus calves. Thus, this study was designed to investigate the possibility that this decreased survival rate may be attributed to dam colostral immunoglobulin (Ig) concentrations and subsequent calf serum Ig concentrations. The specific objective was to determine the effect of breed type of calf on colostrum production, immunoglobulin concentrations in colostrum and calf serum, and availability and absorption efficiency of Ig. Brahman (B) and Angus (A) cattle were reciprocally mated to produce calves of the following types: A x A (n = 8), A x B (n = 9), B x B (n = 11), and B x A (n = 11). At birth, calves were separated from their dams and a blood sample was collected before feeding pooled colostrum (30 mL/kg birth weight) at 1 and 6 h of age. From 6 to 12 h of age, each calf was placed in a box that allowed interaction with the dam but prevented suckling. At 12 h of age, each calf was fed its dam's colostrum and placed with the dam. Additional blood samples were collected at 12, 24, and 48 h after birth. Serum and colostrum samples were analyzed for IgG, IgG1, IgG2, IgM, and IgA using single radial immunodiffusion (RID) assay techniques. The cows were hand-milked after induction of milk letdown with oxytocin at 1 and 12 h after calving. Colostrum volume was recorded, and samples were collected. Brahman cows produced more (P < .001) colostrum at 1 and 12 h than A cows. Total Ig concentrations were obtained by summing IgG, IgG1, IgG2, IgM, and IgA concentrations. Total Ig (P < .02), IgG (P < .005), and IgA (P < .01) concentrations in colostrum were greater in cows producing crossbred calves. Total Ig (P < .006), IgG (P < .02), IgG1 (P < .004), and IgG2 (P < .02) available in colostrum were affected by B x B and A x B breed types of calf. Brahman cows had more Ig available at 1 and 12 h than A cows due to increased production of colostrum. Breed type influenced colostral Ig in cattle. Serum concentrations of total Ig, IgG, IgG1, IgG2, IgM, and IgA in the calf and efficiency of absorption at 6 and 12 h were not affected by breed type, sex of calf, or any interaction.