Effects of Late Gestation Supplements Differing in Fatty Acid Amount and Profile to Beef Cows on Cow Performance, Steer Progeny Growth Performance through Weaning, and Relative mRNA Expression of Genes Associated with Muscle and Adipose Tissue Development.

Strategic supplementation during late gestation has the potential to alter progeny performance. Mature fall-calving Simmental × Angus cows were used to evaluate the effects of late gestation supplementation of fatty acids to beef cows on cow performance, steer progeny growth performance during pre-weaning and backgrounding periods, and relative mRNA expression of genes associated with myogenesis and adipogenesis. Cows (n = 190; 4 pasture groups of cows/treatment) grazed endophyte-infected tall fescue and were supplemented during late gestation with calcium salts of either saturated fatty acid/monounsaturated fatty acid (SFA/MUFA), polyunsaturated fatty acid (PUFA), or an isocaloric and isonitrogenous control (CON). There were no differences (p ≥ 0.11) in cow body weight (BW) or body condition scores from pre-supplementation to weaning or steer BW at birth, weaning, or at the end of the backgrounding period. Concentrations of C18:2n-6 in plasma were greater (p = 0.01) in SFA/MUFA and PUFA cows compared to CON cows during supplementation. For mRNA expression in the longissimus muscle of steer progeny from birth to weaning: PAX7 decreased to a greater (p < 0.01) extent for SFA/MUFA and PUFA steers; AGPAT1 and CPT1 increased to a greater (p ≤ 0.02) extent for CON steers. The expression of MYH7 mRNA during the pre-weaning period was greater (p = 0.01) in PUFA. In conclusion, late gestation fatty acid supplementation modified plasma relative concentrations of fatty acids for dams and progeny and modified mRNA expression of genes related to myogenesis and adipogenesis but had limited effects on progeny growth performance during pre-weaning and backgrounding periods.

Effects of Supplements Differing in Fatty Acid Profile to Late Gestational Beef Cows on Steer Progeny Finishing Phase Growth Performance, Carcass Characteristics, and mRNA Expression of Myogenic and Adipogenic Genes.

The objective was to investigate the effects of feeding late gestational beef cows supplements differing in fatty acid profile on steer progeny finishing phase growth performance, carcass characteristics, and relative mRNA expression of myogenic and adipogenic genes. Seventy Angus-cross steers (initial body weight [BW] 273 ± 34 kg) born from dams supplemented with either 155 g DM/d EnerGII (CON, rich in palmitic and oleic acids) or 80 g DM/d Strata + 80 g DM/d Prequel (PUFA, rich in linoleic acid, eicosapentaenoic acid, and docosahexaenoic acid) for the last 77 ± 6 d prepartum were used. Longissimus muscle and subcutaneous adipose biopsies were collected to evaluate relative mRNA expression of genes related to myogenesis and adipogenesis. Steers were slaughtered at 423 ± 6 d of age. No treatment × time interaction or treatment effect (p ≥ 0.21) was detected for steer finishing phase BW, while steers from PUFA supplemented dams tended (p = 0.06) to have a greater gain to feed ratio (G:F). Neither carcass characteristics nor relative mRNA expression was different (p ≥ 0.11). In conclusion, late gestation PUFA supplementation tended to increase steer progeny finishing phase G:F, but had no effects on finishing phase BW, carcass characteristics, or relative mRNA expression during the finishing phase.

Fetal programming effects of early weaning on subsequent parity calf performance.

Mature Simmental × Angus cows [n = 147; body weight (BW) = 590 ± 72 kg] were used to evaluate the effects of early weaning on subsequent parity calf growth performance and carcass characteristics. Cows were assigned to one of two treatments based on their previous calf's weaning age: early wean (EW) or conventional wean (CW). Dams assigned to the EW treatment had calves previously weaned at 88 ± 6 d of age, whereas dams assigned to the CW treatment had calves previously weaned at 185 ± 6 d of age. Cow BW and body condition scores (BCS) were monitored during the experiment. All cows were managed as a common group from the onset of the experiment at breeding until final pregnancy check of their next production cycle 462 d later. All calves in the experiment were managed as one group and weaned at a single time point, then feedlot performance and carcass characteristics were evaluated. Initial cow BW was different (P < 0.05), so it was included as a covariate for cow BW analysis. There was a treatment × date interaction (P < 0.01) for cow BW and cow BCS. Cow BW was consistently greater for the EW treatment from day 39 to the end of the experiment (P < 0.01). Cow BCS were not different at the onset of the experiment (P = 0.20), although after breeding and throughout lactation, BCS diverged between treatments and the EW treatment consistently had greater (P < 0.01) BCS than the CW treatment throughout the entire subsequent lactation. Gestation length was not different (P = 0.21) between treatments, yet calf birth BW was greater (P = 0.05) for the EW treatment. Neither artificially inseminated pregnancy percentage nor overall pregnancy percentage was different between treatments (P ≥ 0.61). Despite the greater birth BW for the EW treatment and no difference (P = 0.25) in milk production, weaning BW was not different (P = 0.50) between treatments. Feedlot performance measures were not different (P ≥ 0.13) between treatments, including feedlot arrival weight, final BW, average daily gain, dry matter intake, and gain to feed. Final carcass characteristics were not different (P ≥ 0.33) between treatments, including dressing percentage, hot carcass weight, LM area, 12th rib fat thickness, kidney, pelvic, heart fat percentage, USDA yield grade, and marbling score. Thus, early weaning resulted in improved BW and BCS of cows as well as increased birth BW of subsequent calf, although that did not transpire into differences in postnatal growth performance or carcass traits.

Effects of supplements differing in fatty acid profile to late gestational beef cows on cow performance, calf growth performance, and mRNA expression of genes associated with myogenesis and adipogenesis.

BACKGROUND: Maternal nutrition during gestation affects fetal development, which has long-term programming effects on offspring postnatal growth performance. With a critical role in protein and lipid metabolism, essential fatty acids can influence the development of muscle and adipose tissue. The experiment investigated the effects of late gestation supplements (77 d prepartum), either rich in saturated and monounsaturated fatty acids (CON; 155 g/cow/d EnerGII) or polyunsaturated fatty acids (PUFA; 80 g/cow/d Strata and 80 g/cow/d Prequel), on cow performance and subsequent calf growth performance as well as mRNA expression in longissimus muscle (LM) and subcutaneous adipose tissue at birth and weaning. RESULTS: There was no difference (P ≥ 0.34) in cow body weight (BW) or body condition score from pre-supplementation through weaning. Relative concentrations of C18:3n-3 and C20:4n-6 decreased (P ≤ 0.05) to a greater extent from mid-supplementation to calving for PUFA compared with CON cows. Cow plasma C20:0, C20:5n-3, and C22:6n-3 were increased (P ≤ 0.01) in PUFA during supplementation period. At birth, PUFA steers had greater (P = 0.01) plasma C20:5n-3. No differences (P ≥ 0.33) were detected in steer birth BW or dam milk production, however, CON steers tended (P = 0.06) to have greater pre-weaning average daily gain and had greater (P = 0.05) weaning BW compared with PUFA. For mRNA expression in steers: MYH7 and C/EBPß in LM increased (P ≤ 0.04) to a greater extent from birth to weaning for PUFA compared with CON; MYF5 in LM and C/EBPß in adipose tissue tended (P ≤ 0.08) to decrease more from birth to weaning for CON compared with PUFA; SCD in PUFA adipose tissue tended (P = 0.08) to decrease to a greater extent from birth to weaning than CON. In addition, maternal PUFA supplementation tended (P = 0.08) to decrease MYOG mRNA expression in LM and decreased (P = 0.02) ZFP423 in adipose tissue during the pre-weaning stage. CONCLUSIONS: Late gestation PUFA supplementation decreased pre-weaning growth performance of the subsequent steer progeny compared with CON supplementation, which could have been a result of downregulated mRNA expression of myogenic genes during pre-weaning period.

Effects of Maternal Supplementation with an Injectable Trace Mineral Containing Copper, Manganese, Zinc, and Selenium on Subsequent Steer Finishing Phase Performance and Carcass Characteristics.

The objective of this study was to investigate effects of maternal supplementation with an injectable trace mineral (Cu, Mn, Zn, and Se) on subsequent steer performance during the finishing phase. Seventy-six Angus cross steers (initial body weight 249 ± 41.5 kg) from dams administered either an injectable trace mineral (TM; Multimin 90) or sterilized physiological saline (CON) during prepartum stage were used. Individual feed intake during the finishing phase were recorded with GrowSafe feed bunks. Blood and liver biopsy samples were collected to evaluate trace mineral status. Steers were slaughtered at 413 ± 26 days of age and carcass data were obtained at a commercial abattoir. Growth performance or mineral status of the steers during the finishing phase was not affected (p ≥ 0.14) by maternal treatments. Carcass characteristics were not different (p ≥ 0.18), except steers from TM dams had greater (p = 0.05) percentage of carcasses graded as Choice or greater. In conclusion, maternal supplementation of an injectable trace mineral increased the percentage of carcasses graded as Choice or greater, other than that, maternal supplementation had limited influence on finishing phase growth performance, trace mineral status, or carcass characteristics of the subsequent steer progeny.

Effect of increased dietary crude protein levels on production performance, nitrogen utilisation, blood metabolites and ruminal fermentation of Holstein bulls.

OBJECTIVE: This study investigated the effect of dietary crude protein (CP) supplementation on nutrient intake, nitrogen (N) utilisation, blood metabolites, ruminal fermentation and growth performance of young Holstein bulls. METHODS: Twenty-one young bulls weighing 277±11.2 kg were equally divided into three groups and were offered diets formulated with low CP (LCP; 10.21% CP and 4.22% rumen degradable protein [RDP]), medium CP (MCP; 12.35% CP and 5.17% RDP) and high CP (HCP; 14.24% CP and 6.03% RDP). Yellow corn silage was used as a unique forage source and was mixed with concentrate. This mixed feed was given ad libitum to the young bulls included in the study. RESULTS: Results showed that CP intake, blood urea nitrogen, N intake, total N excretion and N balance increased linearly with an increase in dietary CP level (p<0.05). However, no significant difference was observed in nutrient digestibility among the bulls receiving the different diets. Ruminal pH (p<0.05) and ammonia nitrogen (NH3-N) concentration (p<0.01) were significantly higher in the bulls receiving the MCP and HCP diets than in those receiving the LCP diet. The bulls receiving the HCP diet showed significantly higher ruminal bacterial protein level, propionate, acetate and total volatile fatty acid (TVFA) concentrations than bulls receiving the LCP diet (p<0.05). Moreover, dietary CP level exerted a significant positive effect on the final body weight, average daily gain and gain-to-feed ratio of the bulls (p<0.05). CONCLUSION: High dietary CP level is optimal for achieving maximum growth and high profitability without exerting a negative effect on the physiology of growing Holstein bulls.

Applying real-time quantitative PCR to diagnosis of freemartin in Holstein cattle by quantifying SRY gene: a comparison experiment.

BACKGROUND: Freemartinism generally occurs in female offspring of dizygotic twins in a mixed-sex pregnancy. Most bovine heterosexual twin females are freemartins. However, about 10% of bovine heterosexual twin females are fertile. Farmers mostly cull bovine fertile heterosexual twin females due to the lack of a practical diagnostic approach. Culling of such animals results in economic and genetic-material losses both for dairy and beef industry. METHODS: In this study, a comparative test, including qualitative detection of SRY gene by polymerase chain reaction (PCR), quantitative detection of relative content of SRY by real-time quantitative polymerase chain reaction (qPCR), and quantitative detection of H-Y antigen, was performed to establish the most accurate diagnosis for freemartin. Twelve Holstein heterosexual twin females were used in this study, while three normal Holstein bulls and three normal Holstein cows were used as a positive and negative control, respectively. RESULTS: Polymerase chain reaction results revealed that SRY gene were absent in three heterosexual twin females and only two of them were verified as fertile in later age. The qPCR results showed that relative content of SRY was more than 14.2% in freemartins and below 0.41% in fertile heterosexual twin females. The H-Y antigen test showed no significant numerical difference between freemartin and fertile heterosexual twin female. DISCUSSION: Our results show that relative content of SRY quantified by qPCR is a better detection method for diagnosis of freemartin in Holstein cattle as compare to qualitative detection of SRY gene by PCR or quantitative detection of H-Y antigen. To the authors' knowledge, this is the first time we applied qPCR to diagnosing freemartin by quantifying SRY gene and got relative SRY content of each freemartin and fertile heterosexual twin female. We concluded that low-level of SRY would not influence fertility of bovine heterosexual twin female.

Effect of calcium salt of long-chain fatty acids and alfalfa supplementation on performance of Holstein bulls.

The purpose of this study was to assess the effects of calcium salt of long-chain fatty acids (CSFA) and alfalfa on beef cattle in the late fattening. 48 Holstein bulls were selected and randomly divided into 4 groups, feeding four dietary that Leymus chinensis with (LC) or with no (LN) 2.4% CSFA, and alfalfa replaced 50% Leymus chinensis with (AC) or with no (AN) 2.4% CSFA. The results indicated that alfalfa improved the feed conversion rate (P < 0.05). CSFA increased serum low density lipoprotein cholesterol, and reduced the cooking loss of Longissimus muscle (P < 0.05). CSFA and alfalfa reduced Acetate/Propionate. Alfalfa and CASF had significant additive effects on the apparent digestibility of dry matter, crude protein, neutral detergent fiber, acid detergent fiber, organic matter and rumen fermentation for acetate, isobutyrate, butyrate, isovalerate, total volatile fatty acids (P < 0.05). CSFA increased microbial diversity index when compared with alfalfa (P < 0.05), but no significant differences were detected in bacterial genera abundances among diets. The relative abundances of rumen bacterial genera have significant correlation with apparent digestibility of nutrients, rumen fermentation characteristics and serum biochemical parameters (P < 0.05). These results comprehensively evaluated the additive effects of alfalfa and CSFA on the application in Holstein bulls.

Dietary Alfalfa and Calcium Salts of Long-Chain Fatty Acids Alter Protein Utilization, Microbial Populations, and Plasma Fatty Acid Profile in Holstein Freemartin Heifers.

This study presented the effects of alfalfa and calcium salts of long-chain fatty acids (CSFA) on feed intake, apparent digestibility, rumen fermentation, microbial community, plasma biochemical parameters, and fatty acid profile in Holstein freemartin heifers. Eight Holstein freemartin heifers were randomly divided into a 4 × 4 Latin Square experiment with 2 × 2 factorial diets, with or without alfalfa or CSFA. Dietary supplementation of CSFA significantly increased the apparent digestibility of dry matter, crude protein, neutral detergent fiber, organic matter, and significantly reduced N retention (P < 0.05). CSFA increased the concentration of ammonia nitrogen in the ruminal fluid (P < 0.05), but alfalfa increased the concentration of valerate and isovalerate (P < 0.05). CSFA increased the concentration of ammonia nitrogen and the relative population of Streptococcus bovis in the rumen (P < 0.05) and inhibited the relative population of Ruminococcus flavefaciens, methanogens, and protozoa (P < 0.05). Alfalfa instead of Leymus chinensis increased the relative population of Butyrivibrio fibrisolvens and Ruminobacter amylophilus in the rumen (P < 0.05) and reduced the relative population of the Ruminococcus albus and Megasphaera elsdenii (P < 0.05). Supplemental CSFA increased the concentration of cholesterol and low-density lipoprotein cholesterol in the plasma (P < 0.05). And it also altered the composition of fatty acids in the plasma, which was expressed in reducing saturated fatty acid (ΣSFA) ratio and C14-C17 fatty acids proportion except C16:0 (P < 0.05) and increasing the proportion of polyunsaturated fatty acid (ΣPUFA) and unsaturated fatty acid (ΣUFA) (P < 0.05). The results showed that alfalfa and CSFA had interaction effect on the apparent digestibility of ether extracts, plasma triglyceride concentration, isobutyrate concentration, and Ruminococcus albus relative abundance in the rumen. It was concluded that alfalfa substituting Leymus chinensis did not change the apparent digestibility of nutrients in the final stage of fattening Holstein freemartin heifers, while CSFA increased the cholesterol and the proportion of unsaturated fatty acids in plasma. Alfalfa and CSFA had mutual interaction effect on fat digestion and plasma triglycerides.

Effects of replacing Leymus chinensis with whole-crop wheat hay on Holstein bull apparent digestibility, plasma parameters, rumen fermentation, and microbiota.

Twelve Holstein bulls were used in a 4 × 4 Latin square design to investigate the effects of using whole-crop wheat hay (WCWH) as a substitute for Leymus chinensis (LC) on apparent digestibility, plasma parameters, ruminal fermentation, and microbial communities. Experimental treatments were four proportions of WCWH, 0, 33, 67, and 100%, as a substitute for LC (WCWH0, WCWH33, WCWH67, and WCWH100, respectively). The WCWH100 group showed a higher nutritional intake of crude protein (CP) and higher apparent digestibility of organic matter (OM), CP, and ether extract (EE) than the WCWH0 group (P < 0.05). Urea N, NH3-N, isobutyrate and isovalerate levels were higher (P < 0.05) in the WCWH100 group than in the WCWH0 group. 16S rRNA high-throughput sequencing analysis revealed similarities in the community composition, species diversity and relative abundance of dominant bacteria at the phylum and genus levels among the four groups. Collectively, our data indicated that WCWH can be used to replace LC in the diet of finishing dairy bulls without having a negative impact on apparent digestibility, plasma parameters, and ruminal bacteria composition. These results offer the first deep insight into the effects of replacing LC with WCWH on the performance parameters and rumen microbiota in Holstein bulls, and may aid in ruminant farming.