Animal Science Journal最新文献

The high lactation performance or parity in dairy cows may affect intrauterine oxidative stress (OS) status. This study aimed to investigate the effects of milk yield, blood β-hydroxybutyrate (BHBA) concentrations, and parity on oxidative stress (diacron-reactive oxygen metabolites [d-ROMs]) or antioxidant activity (biological antioxidant potential [BAP]) in the uterine flush fluid of lactating Holstein Friesian dairy cows. Uterine flush fluid samples were collected at 4, 5, 6, and 8 weeks postpartum (n = 43), and d-ROMs and BAP were measured. d-ROMs, BAP, and oxidative stress index (OSI) were investigated in relation to the correlation between milk yield and BHBA concentrations. Cows were classified into primiparous cow groups (P group, n = 11), biparous cow group (B group, n = 5), and the third or more calving groups (M group, n = 27); d-ROMs, BAP, and OSI changes were evaluated across the groups. No significant correlations were noted between milk yield, blood BHBA concentrations, and d-ROMs, BAP, or OSI. The M group exhibited higher d-ROMs and OSI than the P group at 5 weeks, and the M group had a higher OSI than the B group at 6 weeks. Therefore, parity may influence uterine OS and antioxidant activity.

This study aimed to compare the growth of goats grazed in abandoned paddy fields with those raised in confined systems for meat production and to clarify the relationship between plasma metabolites including phytol derivatives and botanical conditions of the field. Eight Saanen goats at 4 months of age were allocated to the grazing and confined groups. Goats in the grazing group were grazed in an abandoned field with a concentrate supplement at 1.2% body weight (BW) from the end of May to early November. Grass silage and concentrate supplement at 1.0% BW were provided to the confined goats. Imperata cylindrica and Boehmeria nivea were the dominant plants in the grazing field. Plant biomass and its utilization reached a maximum in August and then decreased thereafter. Although the BW of goats in both groups was almost comparable until the end of September, the grazing goats showed a lower final BW than those in the confined group. Plasma concentrations of urea, total cholesterol, nonesterified fatty acids, lactate, amino acids, and phytanic acid in grazing goats fluctuated throughout the experimental period. These plasma metabolites can be used to monitor the nutritional condition of goats and botanical conditions of grazing fields.

This study examined the effect of replacing low-quality alfalfa hay (AH) with corn silage (CS) in basal forage diets on nitrogen (N) utilization and milk performance of crossbred Hu ewes at different lactation stages (LS1, 32–41; LS2, 84–93 days in milk). Diets used were CON (0% CS, 33.7% AH, 37.2% oat hay [OH]), CS1 (9.2% CS, 23.8% AH, 37.6% OH), and CS2 (18.5% CS, 13.8% AH, 38.0% OH). In a completely randomized design, 12 ewes received the diets formulated to have comparable metabolizable energy and protein content. The N intake was highest in CS2, and rumen degradable organic matter intake increased as the proportion of CS increased. The apparent nutrient digestibility was higher in CS diets than in the CON diet. The CS diets showed significantly lower urinary N excretion rate with their higher N retention rate compared with CON, indicating improved N utilization efficiency in CS diets. Compared with CON, CS2 increased milk yield by 36%, and CS diets increased milk protein and fat content. Overall, partial substituting CS for AH improved N utilization variables and lactation performance, suggesting that a CS-containing forage diet may enhance economic benefits of lactating sheep in the northwestern dryland regions of China.

We compared conception rates among Japanese Black cows undergoing ovulation synchronization protocols using intravaginal progesterone-releasing devices (CIDR) across three different treatment durations. Cows received CIDR treatment for 7 days in the Ovsynch (OS) group (n = 40), 8–10 days in the short-extended (SE) group (n = 42), and 11–14 days in the long-extended (LE) group (n = 67). Gonadotropin-releasing hormone (GnRH) was injected concurrently with the CIDR insertion. On the day of CIDR withdrawal (Day 0), all cows received a prostaglandin F_2α injection. When estrus signs were visually observed from Days 0 to 2, artificial insemination (AI) was performed concurrent with the GnRH injection. Cows without any estrus signs received GnRH injection on Day 2, followed by timed AI 16–20 h later. Data from 149 AIs performed on 144 cows were analyzed. The LE group tended to show a higher estrus expression rate than the OS group (13.4% vs. 0.0%, respectively). Pregnancy per AI was comparable among all three groups (OS: 47.5%, SE: 47.6%, LE: 50.7%). In conclusion, extending the CIDR treatment duration did not affect the conception rates of Japanese Black cows. In LE group cows, AI following estrus detection is recommended to enhance pregnancy outcomes.

Milk fatty acids (FA) are potential indicators of the nutritional status and reproductive performance of dairy cows. We investigated the relationship between FA until 125 days in milk (DIM) and the first insemination conception rates (CR) until 200 DIM. We used monthly test-day milk and insemination records of Holstein cows during the first and the second lactations. FA compositions included de novo FA (DnF: C4:0–14:0) and preformed FA (C15:0 and ≥ C17:0) on a total FA basis. We investigated CR of cows with different FA levels and insemination DIMs. FA compositions tested within 35, 36–65, 66–95, and 96–125 DIMs were leveled as low, moderate, or high. Insemination DIMs were grouped as 66–95, 96–125, and 126–200 DIM. During the first lactation, the CR until 125 DIM was significantly lower in low DnF until 125 DIM than in moderate and high DnF. During the second lactation, the CR until 95 DIM was significantly lower in low and moderate DnF within 35 DIM than in high DnF. These results suggest that DnF within 125 DIM during the first lactation and within 35 DIM during the second lactation are associated with CR until 125 DIM and 95 DIM, respectively.