Journal of Dairy Science® 2022 Editorial Report

In 2022, the 105th volume of the Journal of Dairy Science was published. As we review the journal’s last year, it may be useful to reflect on the purpose of scientific publishing. This can be simply stated as the dissemination of results that extends knowledge to open the door for new concepts or advances in the field (Chan, 2018). Similar to other journals, in addition to original research articles, Journal of Dairy Science also publishes invited reviews and other paper types to pursue this purpose. The journal also has other valuable roles. For example, scientific journals actively support authors in their creative practices while also playing a role in interpersonal interactions of the scientific community. For the Journal of Dairy Science, the year began with the release of our first gold open access issue (Kononoff, 2022). This has increased the exposure of our authors’ work to a larger audience while also aligning authors to open access publishing policies such as the Plan S initiative of cOAlition S (https://www.coalition-s.org/ ). The change has also enhanced access to Journal of Dairy Science content for dairy scientists and dairy industry professionals in developing countries

Systemic and Intra-Habenular Activation of the Orphan G Protein-Coupled Receptor GPR139 Decreases Compulsive-Like Alcohol Drinking and Hyperalgesia in Alcohol-Dependent Rats.

GPR139 is an orphan G protein-coupled receptor (GPCR) that is expressed mainly in the brain, with the highest expression in the medial habenula. The modulation of GPR139 receptor function has been hypothesized to be beneficial in the treatment of some mental disorders, but behavioral studies have not yet provided causal evidence of the role of GPR139 in brain dysfunction. Because of the high expression of GPR139 in the habenula, a critical brain region in addiction, we hypothesized that GPR139 may play role in alcohol dependence. Thus, we tested the effect of GPR139 receptor activation using the selective, brain-penetrant receptor agonist JNJ-63533054 on addiction-like behaviors in alcohol-dependent male rats. Systemic administration of JNJ-63533054 (30 mg/kg but not 10 mg/kg, p.o.) reversed the escalation of alcohol self-administration in alcohol-dependent rats, without affecting water or saccharin intake in dependent rats or alcohol intake in nondependent rats. Moreover, systemic JNJ-63533054 administration decreased withdrawal-induced hyperalgesia, without affecting somatic signs of alcohol withdrawal. Further analysis demonstrated that JNJ-63533054 was effective only in a subgroup of dependent rats that exhibited compulsive-like alcohol drinking. Finally, site-specific microinjection of JNJ-63533054 in the habenula but not interpeduncular nucleus (IPN) reduced both alcohol self-administration and withdrawal-induced hyperalgesia in dependent rats. These results provide robust preclinical evidence that GPR139 receptor activation reverses key addiction-like behaviors in dependent animals, suggest that GPR139 may be a novel target for the treatment of alcohol use disorder, and demonstrate that GPR139 is functionally relevant in regulating mammalian behavior

Supplemental Table 1. Influence of the count of positive days on DMI, milk yield, milk fat, milk protein, and pregnancy rate

Response Intercept Devstarch Devfat DevNDF DevPro BI

Estimation of the Proportion of Feed Protein Digested in the Small Intestine of Cattle Consuming Wet Corn Gluten Feed

The objectives of this study were to expand the database and determine the intestinal digestibility of rumen undegradable protein (dRUP) of common dairy feeds and to determine the effects of feeding 37.9% wet corn gluten feed on these estimates. Two ruminally and duodenally fistulated steers were assigned randomly to a crossover design with 4-wk periods. The mobile bag technique was used to determine rumen undegradable protein (RUP), dRUP, total tract digestible protein, and total tract digestible dry matter of alfalfa hay, brome hay, alfalfa haylage, corn silage, whole cottonseed, soybean meal, soyhulls, ground corn, nonenzymatically browned soybean meal, and dried distillers grains. There was no consistent effect of diet on RUP, dRUP, total tract digestible protein, and total tract digestible dry matter. The RUP (% of crude protein) ranged from 5.97% for alfalfa haylage to 75.6% for nonenzymatically browned soybean meal. The dRUP ranged from 15.3% for alfalfa haylage to 96.5% for nonenzymatically browned soybean meal. The dRUP for alfalfa hay (33.9%), brome hay (39.1%), alfalfa haylage (15.5%), and corn silage (19.9%) were lower than National Research Council reported values. The higher dRUP of the nonenzymatically browned soybean meal is reflective of more total protein reaching the small intestine. The large range in dRUP was not reflected in total tract digestible protein (% of crude protein), with corn silage being the lowest at 85.2% and nonenzymatically browned soybean meal the highest at 97.9%. In this study, diet had little effect on intestinal digestibility of protein or dry matter

Short communication: Detection of yeast DNA in omasal digesta of dairy cows consuming dried distillers grains and solubles

Purine analysis is widely used to estimate microbial crude protein (MCP) flow, and the method assumes that all purines contained in feed are degraded in the rumen and that purines detected are of microbial origin. The objectives of our experiment were (1) to determine if DNA from yeast (Saccharomyces cerevisiae) contained in dried distillers grains and solubles (DDGS) escapes degradation in the rumen and (2) to estimate the proportion of yeast DNA compared with total bacterial DNA in omasal samples. Two ruminally fistulated Holstein dairy cows averaging 649 kg (SD = 42.0) and 126 d in milk (SD = 28.9) were fed in a crossover design during 2 periods of 21 d each. Treatments were (1) control, a total mixed ration (TMR) not containing DDGS and (2) a DDGS-based diet, a TMR in which DDGS were included at 30% of diet dry matter (DM). On d 20 and 21 at 0400 and 1600 h, omasal digesta samples were collected via a ruminal cannula, and DNA was extracted from each sample in duplicate. The DNA samples were subjected to a realtime PCR assay to detect the presence of DNA from yeast. Forward and reverse primers and a probe were designed to target a DNA segment contained on the second chromosome of Saccharomyces cerevisiae. Realtime PCR amplification curves indicated the presence of yeast DNA in samples from both treatments. Specifically, the estimate of relative abundance of yeast DNA from digesta samples collected from animals consuming the diet containing DDGS was 9.46 ± 0.67/g of DM and was significantly higher than that from animals consuming no DDGS, which was observed to be 0.091 ± 0.67/g of DM. Omasal samples were also analyzed for total bacterial DNA. Primers and a probe were designed from DNA encoding part of the 16S rRNA. When the DDGS-based diet was fed, the relative abundance of total bacterial DNA tended to increase from 610 to 626 ± 3.82/g of DM. Results suggest that yeast DNA is detected in the omasum and this is increased when cows consume DDGS but it does not represent a significant proportion of total microbial DNA in the omasal digesta samples

Nociceptin attenuates the escalation of oxycodone self-administration by normalizing CeA-GABA transmission in highly addicted rats.

Approximately 25% of patients who are prescribed opioids for chronic pain misuse them, and 5 to 10% develop an opioid use disorder. Although the neurobiological target of opioids is well known, the molecular mechanisms that are responsible for the development of addiction-like behaviors in some but not all individuals are poorly known. To address this issue, we used a unique outbred rat population (heterogeneous stock) that better models the behavioral and genetic diversity that is found in humans. We characterized individual differences in addiction-like behaviors using an addiction index that incorporates the key criteria of opioid use disorder: escalated intake, highly motivated responding, and hyperalgesia. Using in vitro electrophysiological recordings in the central nucleus of the amygdala (CeA), we found that rats with high addiction-like behaviors (HA) exhibited a significant increase in γ-aminobutyric acid (GABA) transmission compared with rats with low addiction-like behaviors (LA) and naive rats. The superfusion of CeA slices with nociceptin/orphanin FQ peptide (N/OFQ; 500 nM), an endogenous opioid-like peptide, normalized GABA transmission in HA rats. Intra-CeA levels of N/OFQ were lower in HA rats than in LA rats. Intra-CeA infusions of N/OFQ (1 μg per site) reversed the escalation of oxycodone self-administration in HA rats but not in LA rats. These results demonstrate that the downregulation of N/OFQ levels in the CeA may be responsible for hyper-GABAergic tone in the CeA that is observed in individuals who develop addiction-like behaviors. Based on these results, we hypothesize that small molecules that target the N/OFQ system might be useful for the treatment of opioid use disorder

Short communication: Detection of yeast DNA in omasal digesta of dairy cows consuming dried distillers grains and solubles

Purine analysis is widely used to estimate microbial crude protein (MCP) flow, and the method assumes that all purines contained in feed are degraded in the rumen and that purines detected are of microbial origin. The objectives of our experiment were (1) to determine if DNA from yeast (Saccharomyces cerevisiae) contained in dried distillers grains and solubles (DDGS) escapes degradation in the rumen and (2) to estimate the proportion of yeast DNA compared with total bacterial DNA in omasal samples. Two ruminally fistulated Holstein dairy cows averaging 649 kg (SD = 42.0) and 126 d in milk (SD = 28.9) were fed in a crossover design during 2 periods of 21 d each. Treatments were (1) control, a total mixed ration (TMR) not containing DDGS and (2) a DDGS-based diet, a TMR in which DDGS were included at 30% of diet dry matter (DM). On d 20 and 21 at 0400 and 1600 h, omasal digesta samples were collected via a ruminal cannula, and DNA was extracted from each sample in duplicate. The DNA samples were subjected to a realtime PCR assay to detect the presence of DNA from yeast. Forward and reverse primers and a probe were designed to target a DNA segment contained on the second chromosome of Saccharomyces cerevisiae. Realtime PCR amplification curves indicated the presence of yeast DNA in samples from both treatments. Specifically, the estimate of relative abundance of yeast DNA from digesta samples collected from animals consuming the diet containing DDGS was 9.46 ± 0.67/g of DM and was significantly higher than that from animals consuming no DDGS, which was observed to be 0.091 ± 0.67/g of DM. Omasal samples were also analyzed for total bacterial DNA. Primers and a probe were designed from DNA encoding part of the 16S rRNA. When the DDGS-based diet was fed, the relative abundance of total bacterial DNA tended to increase from 610 to 626 ± 3.82/g of DM. Results suggest that yeast DNA is detected in the omasum and this is increased when cows consume DDGS but it does not represent a significant proportion of total microbial DNA in the omasal digesta samples

Effects of chemical composition variation on the dynamics of ruminal fermentation and biological value of corn milling (co)products

The objectives of this study were to evaluate the dynamics of gas production of several corn (co)products, to develop equations to predict the rate of ruminal fiber digestion, to estimate total digestible nutrients (TDN) and net energy for lactation (NEL), and to assess the stochasticity of chemical composition and nutritive value variability. Four corn milling (co)products were evaluated in this study: high protein dried distillers grains (HP-DDG), corn bran (BRAN) and dehydrated germ (GERM), and a dried distillers grains plus soluble produced with a low-heat drying process (BPX). Alfalfa hay was used as an internal standard feed in the in vitro fermentation dynamics analysis. Standard chemical analyses, in vitro digestibility, and in vitro gas production techniques were used to obtain the necessary physicochemical characterization of feeds. The in vitro dry matter digestibility at 24 and 48 h of incubation decreased exponentially as acid detergent insoluble nitrogen increased. However, the degree of in vitro dry matter digestibility reduction was more accentuated at 24 than at 48 h of incubation. The difference among these feeds regarding the dynamics of the anaerobic fermentation within different substrates (intact feed, and fiber and defatted residues) was evaluated. Results suggested that the proportion of fiber digested in the rumen was affected by the degree of sample processing and fat removal. Fractional fermentation rate (kf) of neutral detergent residue (without sodium sulfite) and defatted fiber residue for BRAN, GERM, HP-DDG, and BPX was estimated to be 0.0635 and 0.0852 h−1, 0.0803 and 0.0914 h−1, 0.118 and 0.117 h−1, and 0.0695 and 0.0844 h−1, respectively. The most influential variables affecting kfNDR of HP-DDG and BPX also affected the predicted TDN, suggesting that fiber quality is essential to ensure higher TDN values for these feeds. Our study indicated that it is possible to routinely quantify the rate of fiber digestion and this approach may be based on common analytical procedures namely estimates of neutral detergent fiber, acid detergent fiber, acid detergent insoluble nitrogen, ether extract, and acid detergent lignin. Our simulations of TDN values demonstrated that differences in fermentability and chemical composition of these corn (co)products might considerably affect the supply of energy to lactating dairy cow. The analytical methods developed in this study may serve as a valuable tool to assess nutrient quality and uniformity when samples differ in chemical composition

Effects of chemical composition variation on the dynamics of ruminal fermentation and biological value of corn milling (co)products

The objectives of this study were to evaluate the dynamics of gas production of several corn (co)products, to develop equations to predict the rate of ruminal fiber digestion, to estimate total digestible nutrients (TDN) and net energy for lactation (NEL), and to assess the stochasticity of chemical composition and nutritive value variability. Four corn milling (co)products were evaluated in this study: high protein dried distillers grains (HP-DDG), corn bran (BRAN) and dehydrated germ (GERM), and a dried distillers grains plus soluble produced with a low-heat drying process (BPX). Alfalfa hay was used as an internal standard feed in the in vitro fermentation dynamics analysis. Standard chemical analyses, in vitro digestibility, and in vitro gas production techniques were used to obtain the necessary physicochemical characterization of feeds. The in vitro dry matter digestibility at 24 and 48 h of incubation decreased exponentially as acid detergent insoluble nitrogen increased. However, the degree of in vitro dry matter digestibility reduction was more accentuated at 24 than at 48 h of incubation. The difference among these feeds regarding the dynamics of the anaerobic fermentation within different substrates (intact feed, and fiber and defatted residues) was evaluated. Results suggested that the proportion of fiber digested in the rumen was affected by the degree of sample processing and fat removal. Fractional fermentation rate (kf) of neutral detergent residue (without sodium sulfite) and defatted fiber residue for BRAN, GERM, HP-DDG, and BPX was estimated to be 0.0635 and 0.0852 h−1, 0.0803 and 0.0914 h−1, 0.118 and 0.117 h−1, and 0.0695 and 0.0844 h−1, respectively. The most influential variables affecting kfNDR of HP-DDG and BPX also affected the predicted TDN, suggesting that fiber quality is essential to ensure higher TDN values for these feeds. Our study indicated that it is possible to routinely quantify the rate of fiber digestion and this approach may be based on common analytical procedures namely estimates of neutral detergent fiber, acid detergent fiber, acid detergent insoluble nitrogen, ether extract, and acid detergent lignin. Our simulations of TDN values demonstrated that differences in fermentability and chemical composition of these corn (co)products might considerably affect the supply of energy to lactating dairy cow. The analytical methods developed in this study may serve as a valuable tool to assess nutrient quality and uniformity when samples differ in chemical composition