Concentration and heritability of immunoglobulin G and natural antibody immunoglobulin M in dairy and beef colostrum along with serum total protein in their calves

Immunoglobulin (Ig) G and natural antibody (NAb) IgM are passively transferred to the neonatal calf through bovine colostrum. Maternal IgG provides pathogen- or vaccine-specific protection and comprises about 85 percent of colostral Ig. Natural antibody IgM is less abundant but provides broad and non-specific reactivity, potentially contributing to protection against the dissemination of pathogens in the blood (septicemia) in a calf’s first days of life. In the dairy and beef industries, failure of passive transfer (FPT) of colostral Ig (serum total protein (STP) <5.2 g/dL) is still a common concern. The objectives of this study were to, i) compare colostral IgG concentrations and NAb-IgM titers between dairy and beef cows; ii) assess the effect of beef breed on colostral IgG; iii) compare passive transfer of colostral Ig in dairy and beef calves; and iv) estimate the heritability of colostral IgG and NAb-IgM. Colostrum was collected from Holstein dairy (n=282) and crossbred beef (n=168) cows at the University of Guelph dairy and beef research centres. Colostral IgG was quantified by radial immunodiffusion and NAb-IgM was quantified by an enzyme-linked immunosorbent assay. In dairy (n=308) and beef (n=169) calves, STP was estimated by digital refractometry. Beef cows had significantly greater colostral IgG (146.5 ± 9.5 SEM g/L) than dairy cows (92.4 ± 5.2 g/L, p <0.01). Beef cows with a higher proportion of Angus ancestry had significantly lower colostral IgG (125.5 ± 5.8 g/L) than cows grouped as “Other” (142.5 ± 4.9 g/L, p= 0.02). Using the FPT cut-off, 13% of dairy and 16% of beef calves had FPT; still, beef calves had a significantly larger proportion with excellent passive transfer (STP ≥6.2 g/dL, p <0.01). The heritability of colostral IgG was 0.04 (± 0.14) in dairy and 0.14 (± 0.32) in beef. Colostral NAb-IgM titers in dairy (12.12 ± 0.22, log2 (reciprocal of titer)) and beef cows (12.03 ± 0.19) did not differ significantly (p=0.71). The range of NAb-IgM titers was 9.18 to 14.60, equivalent to a 42-fold range in antibody concentration. The heritability of colostral NAb was 0.24 (± 0.16) in dairy and 0.11 (± 0.19) in beef cows. This study is the first to compare colostral NAb-IgM between dairy and beef cows. Based on the range in NAb-IgM titers and the heritability, selective breeding may improve colostrum quality and protection for neonatal calves in the early days of life.

Genetic Parameters for Growth, Ultrasound and Carcass Traits in New Zealand Beef Cattle and Their Correlations with Maternal Performance

Research has shown that enhancing finishing performance in beef cows is feasible; however, any adverse impact of selection strategies for finishing performance on the performance of the maternal herd should be taken into account. The aim of this research was to examine the inheritance of growth, ultrasound and carcass traits in finishing beef cattle and to evaluate their correlations with maternal performance traits. Data were collected from a nationwide progeny test on commercial New Zealand hill country farms comprising a total of 4473 beef cows and their progeny. Most finishing traits were moderately to highly heritable (0.28–0.58) with the exception of meat or fat colour and ossification (0.00–0.12). Ultrasound scan traits had high genetic correlations with corresponding traits measured at slaughter (rg = 0.53–0.95) and may be used as a selection tool for improved genetic merit of the beef carcass. Fat content determined via ultrasound scanning in the live animal or at slaughter in finishing cattle is positively genetically correlated with rebreeding performance (rg = 0.22–0.39) in female herd replacements and negatively correlated with mature cow live weight (rg = −0.40 to −0.19). Low-magnitude associations were observed between the genetic merit for carcass fat traits with body condition in mature cows.

Performance of lactating suckler cows of diverse genetic merit and genotype under a seasonal pasture-based system

The objective of this study was to investigate the effect of genetic merit of the national Irish maternal index and genotype (i.e. beef vs. beef × dairy [BDX]) of beef cows and subsequent performance of their progeny. With the exception that high genetic merit cows produced 0.57 kg more milk and tended to have 0.04 of a lower body condition score (BCS), no significant differences were observed between cows of diverse genetic merit. Differences between contrasting cow genotype were apparent. Beef cows were 50 kg heavier and had a BCS 0.27 greater than BDX cows. The BDX cows produced 1.67 kg more milk and had a greater 24-d submission rate than beef cows. Calves generated from BDX cows were 19 kg heavier at weaning and were worth €51 more than progeny generated from beef cows. Beef cow progeny, however, had 0.77 of a greater conformation score at slaughter than BDX. While differences were observed across cows of different replacement strategies, results from the current study showed that genetic selection for national maternal index had no effect on the overall performance of suckler cows in a pasture-based spring-calving system.

A mathematical nutrition model adequately predicts beef and dairy cow intake and biological efficiency

The beef cow-calf sector accounts for 70% of feed consumed and greenhouse gases emitted for the beef industry, but there is no straightforward method to measure biological efficiency in grazing conditions. The objective of this study was to evaluate a mathematical nutrition model to estimate the feed intake and biological efficiency of mature beef cows. Data from dams (N = 160) and their 2 nd and 3 rd progeny (312 pairs) were collected from 1953 through 1980. Individual feed intake was measured at 28-d intervals year-round for dams and during 240-d lactation for progeny. Body weights of progeny were measured at 28-d intervals from birth to weaning, and of dams at parturition and weaning each production cycle. Milk yield of dams was measured at 14-d intervals. Dam ME intake (DMEI) and milk energy yield (MEL) of each cow was predicted using the Cattle Value Discovery System beef cow (CVDSbc) model for each parity. Biological efficiency (Mcal/kg) was computed as the ratio of observed or predicted DMEI to observed calf weaning weight (PWW). Pearson correlation coefficients were computed using corr.test function and model evaluation was performed using the epiR function in R software. Average (SD) dam weight, PWW, DMEI, and observed MEL were 527 (86) kg, 291 (47) kg, 9584 (2701) Mcal/production cycle, and 1029 (529) Mcal, respectively. Observed and predicted DMEI (r = 0.93 and 0.91), and observed and predicted MEL (r = 0.58 and 0.59) were positively correlated for progeny 2 and 3, respectively. The CVDS beef cow model under-predicted DMEI (mean bias = 1120 ± 76 Mcal, 11.7% of observed value) and MEL (mean bias = 30 ± 25 Mcal, 2.9% of observed value). Observed and predicted progeny feed intake were not correlated (r = 0.01, P-value = 0.79). Observed and predicted biological efficiency were positively correlated (r = 0.80 and 0.80, P-value ≤ 0.05) for parity 2 and 3, respectively, and the CVDSbc model under-predicted biological efficiency by 11% (mean bias = 3.59 ± 0.25 Mcal/kg). The CVDSbc provides reasonable predictions of feed intake and biological efficiency of mature beef cows, but further refinement of the relationship between calf feed intake and milk yield is recommended to improve predictions. Mathematical nutrition models can assist in the discovery of the biological efficiency of mature beef cows.

Estimation of Energy Expenditure in Breeding Cows Grazing Rangelands with Different Herbage Allowance

The energy partitioning between total heat production (HP) and retained energy (RE) on the efficiency of energy use was evaluated throughout the annual production cycle (gestation-lactation) of 46 multiparous beef cows grazing on two herbage allowances (HA) of Campos grassland (4 vs. 7 kg dry matter/kg body weight; BW; LO vs. HI). Total RE was greater (P < 0.01) for HI than LO cows and presented minimum values during early gestation and maximum values during early lactation associated to the greater (P = 0.02) RE-milk in the former ones. Whole-animal HP, estimated by the heart rate-O2 pulse technique, and cow metabolized energy (ME) intake did not differ between HA treatments, but relative to BW0.75, HP was greater (P = 0.04) for LO than HI cows. Total HP and ME intake were minimum in gestation and maximum in early lactation and ME intake was greater during early lactation for HI than LO cows, and per unit of BW0.75, tended (P < 0.10) to be less for HI than LO cows in winter. The energy efficiency of the annual cycle was not affected by treatments (0.19 vs. 0.12 ± 0.02 for HI and LO respectively; P > 0.10) and there were no differences between treatments in terms of grams of calf per MJ of ME intake (P > 0.10). Management of grazing intensity of Campos grasslands with high herbage allowance improved energy balance of the beef cow-calf system through partitioning of cow ME intake towards RE instead of maintenance.

Improvement of beef cattle cow’s pregnancy rate using an effective dose of Galectin-1

Galectins are cited in the literature as multifunctional molecules that participate in several biological processes such as adhesion, proliferation and cell cycle, apoptosis, RNA processing, control of the inflammatory processes, and physiological mechanisms of reproduction. Galectin-1 has been cited as a mediator involved in preventing early embryonic death in mammals. Exogenous GAL-1 (eGAL-1) can be found, present in Tolerana®. The goal of this study was to evaluate whether eGAL-1 can improve the pregnancy rate after a complementary AI procedure. The pregnancy rate was analyzed by determining the pregnancy status by ultrasound, 25 to 35 days after Timed Artificial Insemination (TAI) of dams (n=3,469 beef cows). The effectiveness of GAL-1 was evaluated by comparing the pregnancy rate of two groups (Treatment and Control Groups) in 107 contemporaries’ groups (YG) established by the statistical model formed. Based on this, the single dose of eGAL-1 and correct administration can increase the probability of obtaining the pregnancy rate in beef cattle up to 8.68% (p < 0.0001). The recommendation to use a dose of eGAL1 during a TAI procedure was reasonable in beef cattle routine. In average, the whole procedure, using eGAL-1, spent 10 ± 5 seconds more time than the conventional procedure.