Factors that affect heat production in lactating Jersey cows

Energy and nitrogen utilization of lactating dairy cattle fed increasing inclusion of a high-protein processed corn coproduct

Advancing technologies of the corn dry-milling ethanol production process includes the mechanical separation of fiber-containing particles from a portion of plant- and yeast-based nitrogenous particles. The resulting high-protein processed corn coproduct (HPCoP) contains approximately 52% crude protein (CP), 36% neutral detergent fiber (NDF), 6.4% total fatty acids (TFA). The objective of this experiment was to examine the effects of replacing nonenzymatically browned soybean meal with the HPCoP on dry matter intake (DMI), energy and N utilization, and milk production of lactating Jersey cows. Twelve multiparous Jersey cows were used in a triplicated 4 × 4 Latin square design consisting of four 28-d periods. Cows were blocked by milk yield and assigned randomly to 1 of 4 treatment diets that contained HPCoP (dry matter [DM] basis) at (1) 0%; (2) 2.6%; (3) 5.4%; and (4) 8.0%. Diets were formulated to be isonitrogenous and thus replace nonenzymatically browned soybean meal with HPCoP in the concentrate mix, while forage inclusion remained the same across diets. Increasing the concentration of HPCoP had no effect on DMI (mean ± SE; 19.9 ± 0.62 kg/d), but tended to linearly increase milk yield (27.8, 28.5, 29.8, and 29.0 ± 1.00 kg/d). Although no difference was observed in the concentration of milk protein with increasing inclusion of HPCoP (3.40% ± 0.057%), the concentration of fat linearly increased with the inclusion of HPCoP (5.05%, 5.19%, 5.15%, 5.47% ± 0.18%). No differences were observed in the digestibility of DM, NDF, CP, TFA, and gross energy averaging 66.6% ± 0.68%, 49.0% ± 1.03%, 66.1% ± 0.82%, 73.6% ± 1.73%, 66.3% ± 0.72%, respectively, with increasing HPCoP inclusion. The concentration of dietary gross energy linearly increased with increasing concentrations of HPCoP (4.25, 4.26, 4.28, and 4.31 ± 0.01 Mcal/kg), but no difference was observed in digestible energy and metabolizable energy (ME) across treatments averaging 2.83 ± 0.033 and 2.53 ± 0.043 Mcal/kg, respectively. Concentration of dietary net energy for lactation (NEL) tended to increase with increasing HPCoP (1.61, 1.72, 1.74, 1.72 ± 0.054 Mcal/kg) with the ratio of NEL:ME increasing linearly with increasing HPCoP inclusion (0.648, 0.676, 0.687, 0.677 ± 0.0124). Results of this study suggest that inclusion of the HPCoP can replace nonenzymatically browned soybean meal and support normal milk production.

Interaction between gestational plane of nutrition and lactation diet composition on lactation performance of Alpine goats of different parities

A study was conducted with 48 multiparous and 31 primiparous Alpine goats to determine the effects of different nutritional planes during gestation and lactation on feed intake, body weight, body condition score and mass index, blood constituent concentrations, and milk yield and composition. Two gestation supplement treatments (GS; Moderate versus High) were imposed for approximately 5.5 months and two lactation diets (LD; Moderate vs. High) within each GS were fed for 16 wk. The Moderate GS (14.2% crude protein; CP) was given at 1.125% body weight (BW; dry matter basis) and the High GS (16.2% CP) was consumed ad libitum, with alfalfa hay available free-choice to all animals. Moderate and High LD contained 16.0 and 16.9% CP and 34.7 and 30.4% neutral detergent fiber, respectively. Body weight (77.5 vs. 72.0 kg) and body condition score (BCS; 3.22 vs. 3.04) at 11 days before kidding were greater (P < 0.05) for High versus Moderate GS, but BW at kidding (62.6 and 64.9 kg; SEM = 1.32) and 3 days later (60.9 and 63.6 kg for Moderate and High GS, respectively; SEM = 1.32) was similar. Litter size (1.9 and 2.4; SEM = 0.59), kid birth weight (3.72 and 3.59 kg; SEM = 0.097), and litter weight (6.55 and 7.13 kg for Moderate and High GS, respectively; SEM = 0.316) were similar between GS diets. However, kid birth weight (3.44 and 3.87 kg; SEM = 0.096) and litter weight (6.23 and 7.46 kg; SEM = 0.364) were greater (P < 0.05) for multiparous versus primiparous goats. Dry matter intake during lactation was greater for Moderate than for High GS (P ≤ 0.051) in kg/day, % BW, and g/kg BW0.75. However, milk fat (3.81, 4.14, 3.85, and 3.77%; SEM = 0.132) and protein concentrations (2.49, 2.50, 2.47, and 2.49%; SEM = 0.047), and raw (2.22, 2.59, 2.39, and 2.45 kg; SEM = 0.173) and energy yields of milk (6.02, 7.42, 6.51, and 6.63 MJ/day for Moderate GS-Moderate LD, Moderate GS-High LD, High GS-Moderate LD, and High GS-High LD, respectively; SEM = 0.453) were not affected by GS, LD, or their interaction. Dry matter intake, milk and its component yields, and heat energy (MJ/day) were higher (P < 0.05) for does than for doelings, but BCS and milk protein and fat concentrations were lower (P < 0.05) for does. Blood nonesterified fatty acid concentration was not affected by any diets, but there was interaction (P < 0.05) between GS and LD for betahydroxybutyric acid concentration. In conclusion, minor to moderate magnitudes of difference in nutritional planes during gestation and lactation had little effect on reproductive and lactation performance, reflecting the considerable capacity of lactating dairy goats for compensatory changes such as feed intake and tissue mobilization and accretion.

Temporal and Regional Differences and Empirical Analysis on Sensitive Factors of the Corn Production Cost in China

The corn production cost (CPC) in China is related to national food security. However, there are few studies on the temporal and regional differences (TRD) and sensitive factors in the CPC. In this paper, the TRD of the corn production cost across various regions, as well as over the entirety of the country from 2008 to 2018, is presented. It is based on the GIS exploratory spatial data analysis method (ESDA). Simultaneously, a spatial panel model is established to conduct an empirical analysis of the main factors affecting the CPC. The results from the period in question show that the CPC in China and the three major production regions present a fluctuating growth trend, mainly associated with the increase in labor prices. Moreover, the CPC exhibits significant spatial differences, and demonstrates an overall trend of gradual increase from the east to the west. Over time, the number of relatively high-cost provinces has increased. All are located in southern mountainous and hilly corn areas. In addition, the CPCs of various regions are spatially correlated. Factors such as the scale of land management, the degree of mechanization, and socioeconomic conditions have a significantly negative impact on the CPC in China. Furthermore, the labor structure has a notably positive impact on the CPC.

Dietary fatty acid and starch content and supplemental lysine supply affect energy and nitrogen utilization in lactating Jersey cows

The effects of dietary fatty acid (FA) and starch content as well as supplemental digestible Lys (sdLys) on production, energy utilization, and N utilization were evaluated. Each factor was fed at 5 different amounts, and factor limits were as follows: 3.0 to 6.2% of dry matter (DM) for FA; 20.2 to 31.3% of DM for starch, and 0 to 17.8 g/d of sdLys. Dietary FA and starch were increased by replacing soyhulls with supplemental fat and corn grain, respectively, and sdLys increased with rumen-protected Lys. Fifteen unique treatments were fed to 25 Jersey cows (mean ± SD; 80 ± 14 d in milk) across 3 blocks in a partially balanced incomplete block design. Each block consisted of 4 periods of 28 d, where the final 4 d were used to determine milk production and composition, feed intake, energy utilization (via total collection and headbox-style indirect calorimetry), and N utilization (via total collection). Response surface models were used to evaluate treatment responses. Increasing dietary FA decreased DM intake and milk protein yield. When dietary starch was less than 24%, milk protein concentration increased with increasing sdLys, but when dietary starch was greater than 26% milk protein concentration decreased with increasing sdLys. Digestibility of FA increased when dietary FA increased from 3.0 to 4.2% and decreased as FA increased beyond 4.2%. Although neutral detergent fiber digestibility decreased as dietary starch increased, energy digestibility increased. As dietary FA increased, metabolizable energy (ME) content quadratically increased. Supply of ME increased as dietary FA increased from 3.0 to 4.2% and decreased as FA increased beyond 4.2%. Increasing dietary FA and starch decreased CH₄ production and urinary energy. Increasing dietary starch increased the efficiency of utilizing dietary N for milk N. Increasing sdLys quadratically decreased N balance as sdLys increased from 0 to 8 g/d and increased N balance as sdLys increased from 8 to 18 g/d. Increasing dietary FA can increase ME content, however, at high dietary FA, decreased DM intake and FA digestibility resulted in a plateau in ME content and a decrease in ME supply. Our results demonstrate that sdLys supply is important for milk protein when dietary starch is low, and some Lys may be preferentially used for muscle protein synthesis at the expense of milk protein when sdLys is high.

Derivation of the maintenance energy requirements and efficiency of metabolizable energy utilization for dry and lactating Jersey cows

Maintenance energy is the energy required to conserve the state of an animal when no work is completed. Dietary energy must be supplied to meet maintenance requirements before milk can be produced. The objectives of the current experiment were to quantify the maintenance energy requirement of Jersey cows when lactating or dry. Energetic measures were collected on 8 Jersey cows and evaluated across 3 physiological phases and nutritional planes: lactation, dry cows fed at maintenance, and fasted dry cows. Through total collection of feces and urine as well as using headbox-style indirect calorimeters, energy balance and heat production data were measured across all phases. Lactation data were collected across four 28-d periods. Data for cows fed at maintenance were collected after 14 d and fasting heat production was measured during the last 24 h of a 96-h fast. Net energy for maintenance (NE_M) requirements, and the efficiency of converting metabolizable energy (ME) into net energy were compared between lactating and dry (maintenance or fasting phase) cows. Heat production of dry cows fed at maintenance, which represents ME for maintenance, was 0.146 ± 0.0087 Mcal per unit of metabolic body weight (BW^0.75, MBW). Fasting heat production, which represents NE_M, was 0.102 ± 0.0071 Mcal/MBW. Energy balance was calculated as tissue energy plus milk energy. When estimated via regressing energy balance on ME intake, NE_M was not different between dry and lactating cows (0.120 ± 0.32 vs. 0.103 ± 0.0052 Mcal/MBW). However, the slope of the regression of energy balance on ME intake was greater for dry compared with lactating cows (0.714 ± 0.046 vs. 0.685 ± 0.010) when evaluated with a fixed intercept. This suggests that dry cows were more efficient at converting ME into net energy and that the efficiency of utilizing ME for maintenance may be greater than for lactation. Our measurements of NE_M and the slope of ME on energy balance were greater than the value used by the National Research Council (2001), which are 0.080 Mcal/MBW for NE_M and approximately 0.64 for the slope. Results of this study suggest that NE_M and the efficiency of converting ME into NE_M of modern lactating Jersey cows are similar to recent measurements on modern Holstein cows and greater than previous measurements.