In addition to reduced nutrient intake, an environmental thermal load may directly affect milk yield in heat-stressed dairy cows. Feeding and lying behaviors of early lactation cows fed low fiber diets containing neutral detergent fiber (NDF) from roughage and nonforage fiber sources (NFFS) were investigated under summer conditions in Thailand. Immediately after calving, 30 multiparous cows (87.5% Holstein × 12.5% Sahiwal) were randomly allocated to dietary treatments for 63 d in a completely randomized design. The dietary treatments contained 25% of dry matter (DM) as dietary NDF. The control diet consisted of 13.9% roughage NDF from rice straw (RS). Two additional treatments were created by replacing 3.9% of DM with NDF from either soy hulls (SH) or cassava (Manihot esculenta Grantz) residues (CR), so that the roughage NDF content was reduced to 10%. During the experimental period, the minimum and maximum temperature-humidity indices (THI) were 86.4±2.5 and 91.5±2.7 during the day and 74.2±2.1 and 81.0±2.5 during the night, respectively, indicating conditions appropriate for induction of extreme heat stress. The duration of feeding and lying bouts decreased linearly with increasing THI. The DM intake during the day was greater for cows fed diets containing SH and CR than for those fed the diet containing NDF from RS. The number of meals during the day and night was lower, whereas meal size and meal length during the day and night were greater for cows fed diets containing SH and CR. Cows fed diets containing SH and CR lay down less frequently and longer during the day. These results suggest that under the severe heat stress during the day, early lactation cows fed the diet containing NFFS increased DM intake by increasing meal length and meal size rather than by increasing meal frequency and they spent more time lying. Cows fed diets containing NDF from SH and CR produced more 4% fat-corrected milk, lost less body weight, and had lower rectal temperatures measured at the 1530h milking. Therefore, reducing the filling effect may contribute to reducing heat load derived from the change in feeding and lying behavior. This should be considered as a factor for impairing productivity of heat-stressed early lactation cows.

Although intravaginal progesterone supplement protocols are commonly used to prepare cattle and river buffalo for insemination or embryo transfer, swamp buffalo have unique reproductive characteristics (such as difficulty of oestrous detection and a small reproductive tract) that make this procedure problematic. Ovulation synchronization (Ovsynch) is a practical alternative preparatory program that does not require oestrous detection and is used worldwide for cattle and river buffalo breeding. Published studies on the efficacy of its use in swamp buffalo, however, are rare. Our objective was to determine the efficacy of the Ovsynch regimen in swamp buffalo in terms of conception rate, economic cost, and potential health complications. Thirty healthy swamp buffaloes (n = 24 cows and n = 6 heifers) were selected by a breeding soundness examination (BSE) as in our previous study (Chaikhun-Marcou et al. 2017 Agric. Sci. J. 48(Suppl.), 929-938). The animals had the following characteristics: >300 kg of body weight, a body condition score of 2.5 to 3.5/5, cervix diameter >2.5 cm, and ovarian diameter >1.5 cm with a dominant follicle (with or without corpus luteum). The standard Ovsynch program was applied in the animals during January to March 2017. All buffaloes were fixed-time inseminated at 20 ± 2 h and 32 ± 2 h after the 2nd gonadotropin-releasing hormone (GnRH) injection. Pregnancy diagnosis was detected by plasma progesterone analysis on Day 24 after insemination (≥1 ng mL−1). Our oestrous synchronization rate, published in a previous study (Chaikhun-Marcou et al. 2017 Agric. Sci. J. 48(Suppl.), 929-938), was 96.67% (n = 29/30). The conception rate was 70% (n = 21/30). This result is much higher than a previous Ovsynch study in swamp buffalo, which was 34% (n = 18/52) (Chaikhun et al. 2010 Theriogenology 74, 1371-1376). This difference demonstrates the importance of pre-screening animals for BSE before subjecting them to this procedure. If this pre-selection protocol is applied, the Ovsynch program, as shown in this study, can be a convenient, effective, and noninvasive preparatory procedure for insemination. Because recipients of both AI and embryo transfer require the same basic biological preconditions, the Ovsynch protocol should be an equally effective preparation for this procedure. Ovsynch, moreover, requires much less labour (only 3 animal handling sessions, with no need for complicated heat detection), entails fewer possible complications (such as the danger of vaginitis when using an intravaginal progesterone device, which can lead to problems with embryonic implantation), and is economically affordable (approximately US$20/animal). In conclusion, the Ovsynch program, combined with BSE pre-screening, could be a practical, stress-free procedure for preparation of swamp buffalo embryo transfer recipients in the near future. This research was sponsored by Agricultural Research Development Agency (PRP5805011500).