The N-acetyl-L-methionine (NALM) molecule is a methionine (Met) derivative produced via acetylation of the L-Met α-amino group with an N-acetyl group. This molecule has been shown to be bioavailable and capable of fulfilling the dietary requirement for Met in animals and humans. The current experiment was conducted to test a hypothesis that lactating dairy cows fed with NALM would increase milk production by increasing N and energy utilization efficiencies in a dose dependent manner. Eight multiparous Holstein cows that were mid lactation (124 ± 13 days-in-milk) with similar milk production were used in a 4 x 4 Latin square design for 84 d. A developmental NALM product from CJ CheilJedang (Seoul, South Korea) was used as the supplemental source of rumen-protected Met in the present study. Four dietary treatments included 0 g (control), 15 g, 30 g, and 45 g/d/cow of NALM supplementation. Supplementing NALM significantly increased dry matter intake (linear effect; P < 0.01), while milk yield tended to increase quadratically (P = 0.07). A linear decrease in milk fat concentration was seen due to supplementation of NALM in relation to the control ration (P = 0.02). However, milk fat yield was similar across treatments. A trend toward an increase in milk protein yield was observed between the control ration and the ration supplemented with 45 g of NALM (1.18 vs. 1.21 kg/d; P = 0.10). There were no differences in energy-corrected or 3.5% fat-corrected milk yields in response to treatments. It is likely that the supplementation of NALM to mid to late lactating dairy cows may have shifted nutrient and energy utilization toward tissue gain and lactation, which resulted in a decrease in feed efficiency for lactation (P = 0.02). Overall results from the present study suggest that supplementing NALM to mid to late lactating cows can increase milk yield in a dose dependent manner with a shift of net energy partitioning toward milk production and body weight gain. In addition, supplementing NALM increased milk nitrogen (N) output without affecting urinary N excretion.

Rumen protected Methionine (MET) and Lysine (LYS) are critical for milk protein synthesis in dairy cows. N-acetyl-L-methionine (NALM) is a MET derivative that consists of L-Met protected with an acetyl group that is attached to the α-amino group.N-acetyl-L-lysine (NALL) is a LYS derivative that is similarly protected. The objectives of these studies were to quantify the gastrointestinal availability of NALM and NALL. Three experiments were run as 3 × 3 Latin square using 3 second lactation Holstein cows that have been fitted with cannulas in the rumen and duodenum. The cows were fed diets containing the supplements for two weeks prior to each experiment so that the rumen microbes had time to adjust to the supplement. Each period consisted of 10 d of adaptation followed by 2 d of sampling. A dose of 0, 30, or 60 g of NALM was placed under the rumen mat at the time of feeding every day during experiment 1. The cows were similarly supplied with 0, 60, or 120 g of ƐNALL during experiment 2. The cows were supplemented with 0 g, 120 g ofƐNALL, or 120 g of diNALL during experiment 3. On day one of sampling, a liquid marker (Co-EDTA) was also administered at the time of the protected AA administration. Blood, ruminal, and duodenal samples were taken at hours 0, 1, 3, 6, 9, 12, and 24 post-feeding. There were no differences for milk production, milk protein, milk fat, or DMI for NALM or either NALL. There were no differences for ruminal escape (69.1% and 46.2% respectively) and duodenal appearance (2.16% and 3.40% respectively). The ruminal escape of ƐNALL was not different between the 120 g dose (32.7%) and the 60 g dose (27.2%). Duodenal appearance was higher (P < 0.01) for the 60 g dose (2.86%) than for the 120 g dose (1.19%) of ƐNALL. Acetate, propionate, butyrate, and valerate were higher (P < 0.01) for the supplemented cows during experiment 1 with NALL. There were no differences between ƐNALL and diNALL for rumen escape, duodenal appearance, VFA production, or blood LYS AUC. Results of the experiment verify significant protection of the N-acetyl MET and LYS from rumen degradation.

Three experiments were conducted using implanted heart rate (HR) transmitters. In the first experiment three lactating Holstein cows' HR signals were monitored telemetrically for three successive days under the normal herd management. Overall mean and standard error for these cows was 76.1 ± 0.46 bpm. In the second experiment the same three cows' HR signals were monitored with a portable computer and receiver. The cows were transported 400 kilometers one way over various road surface conditions. The HR signals were monitored consecutively at the beginning of the trip and at hourly intervals during travel. The cows stayed overnight and were brought back the next day. This two-day journey was repeated one week later. As travel commenced, the cows' HRs averaged 89.7 bpm and differed significantly (p In a second experiment, two cows were exposed to five different types of aircraft noises--helicopter low altitude flyover and hover, fixed-wing low altitude flyover, jet aircraft low altitude subsonic flyover, and high altitude supersonic boom. The cows were exposed to four to five flyovers of the same type of aircraft at approximately five-minute intervals. Intervals between different aircraft type flyovers were at least one hour. Two noise disturbance experiments were conducted seven days apart. Supersonic booms and helicopter flyovers had significant effects on HR response. With increasing exposures to aircraft disturbances, there was a reduction in HR response.

Twenty-four lactating cows were randomly assigned to three treatments within eight each 3 x 3 latin squares with three periods of 21 days duration. Three processing treatments of barley were 1) steam-rolled, 2) ground (fine), and 3) soak-rolled (soaked in water for appr. 24 hours, rolled, and fed within 48 hours). All rations were fed ad libitum and were comprised of 24% alfalfa hay, 16% corn silage, 35.5% barley, 12% whole cottonseed, 12% wheat bran, 0.3% salt, and 0.3% dicalcium phosphate on a dry matter (DM) basis. Electronic doors were used to collect individual feed intake data. Rations and feces grab samples were collected and analyzed chemically. Dry matter digestibility (DMB) was determined by acid insoluble ash. Body weights (BW) were taken every two weeks. Milk production was recorded daily and composition of milk fat, protein, and solids-not-fat (SNF) was determined twice a month. Production (kg/day) of milk, butterfat, protein, SNF; DM consumed (kg); percent DMD; efficiency 1 (kg) 4% fat corrected milk (FCM)/kg DM intake); and efficiency 2 (kg) 4% FCM/kg digestible dry matter (DDM) for rations 1, 2, and 3 were 24.2, 22,7, 21.8; 0.88, 0.80, 0.86; 0.83, 0.78, 0.74; 2.17, 2.04, 2.01; 19.8, 20.8, 18.7; 67.05, 71.05, 67.20; 1.16, 1.04, 1.18; 1.76, 1.46, and 1.83, respectively. The method of processing barley caused significant differences (P<.01) in production of milk, percent fat, amount of protein, DDM, and efficiency 1 and 2. Likewise, it caused significant differences (P<.05) for 4% FCM, amount of fat, and SNF, and DM consumed, but there were no significant differences for SNF, proteing and percent DMD amount of feed consumed and refused, DM refused, and BW. Treatment by period interactions were significant (P<.01) for feed and DM consumed, feed efficiency 1 and 2, and DDM. Group by period interactions were highly significant (P<.05) for BW, (P<.05) for total milk production, and amount of protein. Correlations among all the variables were with those previously reported except for the correlations of percent SNF with total milk production, which was positive but non-significant (P>.05). The cows fed ration 1 produced more total milk and protein than those on rations 2 and 3. There were not differences in feed consumed (or fed) among cows on the three rations. Cows on ration 2 consumed more DM than those on ration 3, but cows on ration 1 did not differ in DM consumption from those on either of the other treatments. Cows on ration 3 had the highest fat test, but showed no differences in the amount of fat produced compared to the cows on rations 1 and 2. Cows on ration 2 had the highest percent DMD and DDM and since these were not the highest in total milk production but were the highest in DM consumption, they were the least feed efficient. Additionally, since cows on ration 3 consumed less DM than those on ration 2, the former had high feed efficiency equal to cows on ration 1.

Twenty-two primiparous Holstein heifers were allocated to one of two treatments. Treatments consisted of: l) basal ration plus 226.8 g inorganic mineral supplement (control); and 2) basal ration plus 226.8 g inorganic mineral and metal proteinate supplement (50:50). Individual heifer performance was measured during the final l 0 weeks of the prepartum period. Feed intake and refusals were recorded daily. Individual heifer body weights recorded weekly did not differ significantly. Blood samples taken at 4-week intervals did not differ in plasma concentration between treatments. Calf birth weights for control heifers were not significantly higher than calves from the treatment heifers. The same twenty-two Holstein heifers used in the prepartum period were assigned to the same treatment groups for the 20-week postpartum lactation period. Treatments consisted of: 1) basal ration plus 453.6 g inorganic mineral supplement (control); and 2) basal ration plus 453.6 g inorganic mineral supplement and metal proteinate supplement (50:50). Dry matter intake and milk yield were recorded daily. Milk composition and body weights were recorded weekly. Feed and fecal samples were collected to determine apparent nutrient digestibility, using acid insoluble ash as an internal marker. Blood samples taken at. 4-week intervals showed no significant difference (Ρ < .05) in plasma mineral composition. No statistical difference was observed in milk yield between treatments (Ρ < .05). Percent lactose in milk samples from the treatment group was significantly higher (Ρ < .05) than that of the control group. Apparent nutrient digestibilities did not differ between treatment groups. Starting on day 5 postpartum, cows were observed for signs of estrus and bred at first observed estrus after 60 days postpartum. Days to first estrus were significantly lower (Ρ< .05) in the treatment group. The feet of each heifer were critically evaluated and scored according to six separate criteria at the start and at the finish of the trial. The texture category of the hoof evaluation score was significantly lower (Ρ < .05), favoring the treatment group over the control group.

Artificial insemination of dairy cattle is one of the recent enterprises of dairymen in this area. It is an enterprise which has expanded rapidly and will likely continue to expand during the next few years. In this area the technician or inseminator collects from $6.00 to $10.00 at the time of first service. This entitles the dairyman to two repeat inseminations for that cow, if necessary, to get the cow pregnant. Of this amount the technician receives $2.75. A bonus payment is made so that technicians inseminating fewer than 500 cows receive a total payment of $3.60. The bonus payment per cow decreases gradually until at 1500 or more cows, no bonus is paid. Payment to the technician is intended to include the value of his time and the mileage necessary to either impregnate the cow or inseminate her three times. Mileage per first service may be affected by size and shape of the area in which a technician operates. The pattern of cow distribution where cows are located in and around the communities may affect mileage. This mileage may be different than in an area with a block pattern of roads with cows located on the farms in all parts of the area. In many of the technician units a small number of first service may be different than in those units where a large number of cows are inseminated. This study was undertaken to determine the mileage traveled to impregnate a cow as affected by the number of first services in a year. The relation of mileage to shape of are serviced by a technician and the number of first services within a year were also studied.

Thirty-five range cows of various breeds were obtained for the study. Body measurements taken were live weight and hip height and all cows were condition scored for level of fatness. The cows were slaughtered and the following morning several carcass measurements were taken and the plate was removed from the left side. These plates were boned and the remaining flesh ground for chemical analysis of percent carcass fat. Regression equations were calculated for estimating percent carcass fat from condition score, weight:height ratio and hip height (R2=.765). However, condition score alone is the single best estimator for percent carcass fat (R2=.759).

Thirty-two lactating cows were assigned at random to four treatments of malic acid to determine if these levels had an effect on milk production, milk composition, feed intake, and efficiency of feed utilization. Malic acid allotment for each treatment consisted of 1) 15.4, 2) 11.6, 3) 7.7, and 4) 0 grams of malic acid fed per kilogram of concentrate. Concentrate was fed according to production at a rate of one kilogram per two kilograms of milk in excess of 9.1 kilograms of milk per cow daily. Alfalfa hay was fed free choice and corn silage at a rate of 11.4 kilograms daily. The cows were on the trial for 8 weeks. Intake of concentrates, silage, dry matter, and digestible energy was highest for cows receiving the 11.6 g level of malic acid. These intakes were significantly higher than for the 7.7 g level but not for the other treatments. However, cows on the 7.7 g level consumed only slightly less feed than control cows. There was no significant effect on hay or crude protein intake. Production of total milk, fat corrected milk, and milk fat was significantly higher for cows receiving the 11.6 g level of malic acid than from the 7.7 g level or control cows. Production of protein solids-not-fat was significantly higher for the 11.6 g level than from the 7.7 g level and approached this level of significance when the 11.6 g level was compared to the controls. Cows receiving the 11.6 g level of malic acid were significantly more efficient in converting dry matter or digestible energy from feed into milk than were the controls. Intakes and production of cows on the 15.4 g level was slightly less than for the 11.6 g level.

Many of the beef cattle in the Great Basin area are maintained part or all of the year on rangelands. Most of those going on to desert ranges for only part of the year go on during the late fall, winter, and early spring. It is estimated that 50-60 percent of the 600,000 beef cattle grazing on range lands in Utah graze on the one-fourth million acres of desert or semi-desert sometime during the year.

Modern high-yielding dairy cows are currently producing far more milk than their ancestors due to a prolonged and intensive genetic selection for milk production trait accompanied by the revolutionary improvement in technology, management, and nutrition. On the other hand, a noticeable decline in fertility and reproductive performance was undeniably consistent with the increase in milk yield. This decline in fertility and reproductive performance are recognized worldwide and well documented in several studies. Dairy cows typically experience a period of energy deficit during the first few months of lactation due to the rapid increase in milk production and limited feed intake. This shortage of energy requirements results in loss of body fat which is associated with the disturbance of the normal levels of certain hormones and metabolites. The significant increase in milk yield has increased the severity and duration of the energy deficit which has an adverse effect on the main reproductive cells and tissues that profoundly contribute to fertility. These include the egg from the ovary, the early embryo, and the internal lining of the uterus. Fertilization of a healthy egg results in the development of an embryo with an excellent quality that can survive through the multiple stages of gestation, especially during the first two weeks of gestation when many embryos die. The embryos in the early stages are the most susceptible to the disturbance in their environment. Energy deficit was shown to negatively impact the egg and embryo quality and make the uterus lining suboptimal to support early embryo development. Understanding the mechanisms by which energy deficit influences the main reproductive tissues will help in developing profound strategies to improve fertility in dairy cows.