The effects of rumen protected methionine supplementation on the performance of primiparous dairy cows using the Presynch-Ovsynch protocol.

The purpose of this study was to examine the effects of rumen-protected methionine (RPM) supplementation on the reproductive and productive performance of primiparous dairy cows fed two levels of protein. The Presynch-Ovsynch protocol was used to synchronize 36 lactating Holstein cows that were assigned randomly to one of six dietary treatments: (1) 14% CP and without RPM diet (14CP-0RPM; n = 6), (2) 14% CP and 15 g/head/day RPM (14CP-15RPM; n = 6), (3) 14% CP and 25 g/head/day RPM (14CP-25RPM; n = 6), (4) 16% CP and without RPM diet (16CP-0RPM; n = 6), (5) 16% CP and 15 g/head/day RPM (16CP-15RPM; n = 6), and (6) 16% CP and 25 g/head/day RPM (16CP-25RPM; n = 6). Independent of CP levels, feeding RPM had reduced the calving interval (P < 0.01). Feeding RPM increased (P < 0.01) overall plasma progesterone (P4). Feeding 16CP-15RPM increased (P < 0.01) overall plasma P4. Feeding 16% CP increased (P < 0.01) 4% fat corrected milk, energy corrected milk, milk fat and protein yield, and milk casein. Moreover, feeding the 25RPM has increased (P < 0.01) 4% fat corrected milk, energy corrected milk, milk fat, and protein yield. Compared with other treatments, feeding 16CP-25RPM or 16CP-15RPM enhanced (P < 0.01) milk yield and milk fat yield. In conclusion, feeding 16% CP with RPM boosted the productivity and reduced the calving interval in primiparous lactating dairy cows.

Sheep with ovarian androgen excess have fibrosis and follicular arrest with increased mRNA abundance for steroidogenic enzymes and gonadotropin receptors.

An androgen excess ovarian micro-environment may limit follicle progression in sheep. Two populations of ewes with divergent follicular fluid androstenedione (A4) were identified in a flock in Jordan: High A4; (A4) ≥ 30 ng/mL, (N = 12) or Control A4 (Control); A4 ≤ 15 ng/mL; (N = 12). We hypothesized High A4 ewes would have increased steroidogenic enzyme mRNA abundance, inflammation, and follicular arrest. Messenger RNA abundance for steroidogenic enzymes StAR, CYP17A1, CYP11A1, and HSD3B1 were increased in theca cells while CYP17A1, CYP19A1, and HSD3B1 were increased in granulosa cells in High A4 ewes compared to Control. Gonadotropin receptor mRNA expression for LHCGR was increased in theca and FSHR in granulosa in High A4 ewes. Messenger RNA expression of FOS when reduced, increases expression of CYP17A1 which was observed in High A4 granulosa cells compared to Control. Furthermore, High A4 ewes had greater numbers of primordial follicles (P < 0.001) and fewer developing follicles compared to Control before, and after 7 d of culture, indicating follicular arrest was not alleviated by cortex culture. Increased fibrosis in the ovarian cortex was detected in High A4 ewes relative to Control (P < 0.001) suggesting increased inflammation and altered extracellular matrix deposition. Thus, this High A4 ewes population has similar characteristics to High A4 cows and women with polycystic ovary syndrome suggesting that naturally occurring androgen excess occurs in multiple species and may be a causative factor in follicular arrest and subsequent female sub- or infertility.

Excess androgen (androstenedione; A4) in ewes can result in ovarian follicular arrest and fibrosis contributing to anovulation in sheep. We have identified a naturally occurring ovarian A4 excess in a sheep population with similar characteristics to High A4 cows, both of which are similar to that in women with polycystic ovary syndrome indicating that several mammalian species experience naturally occurring androgen excess resulting in infertility or follicle arrest. Somatic cells, theca and granulosa, surrounding the egg in High A4 ewes had increased expression of steroidogenic enzymes, similar to that seen in High A4 cows, permitting more ovarian cells to manufacture androgens, which may be the cause of androgen excess. Thus, naturally occurring androgen-excess in domestic livestock females can be utilized as models to research the causes of androgen excess and determine the mechanisms that result in follicular arrest and sub- or infertility.

Effects of dietary betaine on body temperature indices, performance, metabolism, and hematological variables of dairy heifer calves during hot summer conditions.

Background and Aim: Heat stress (HS) can negatively impact farm animal productivity and adversely affect animal welfare worldwide, placing a major financial burden on global livestock producers. Dietary betaine (trimethylglycine) has been known to have several biological functions, which may aid in offering beneficial effects on livestock productivity during HS conditions. However, information on the role of dietary betaine in heat-stressed dairy heifer calves is yet to be documented. Therefore, this study aimed to assess the effects of supplementing dietary betaine on body temperature indices, blood metabolites, productive performance, and complete blood count (CBC) (hematological indices) in hyperthermic dairy heifer calves. Materials and Methods: In total, 14 Holstein heifer calves (4.0 ± 0.9 months old) were individually housed and randomly allocated to one of two dietary treatments: (1) a control diet (CON; n = 7) and (2) a control diet complemented with 21 g/d of natural betaine (BET; n = 7) top-dressed once daily. The experiment lasted for 28 d, during which all animals were subjected to natural cyclic HS conditions (26.1-39.2°C; 73.2-84.0 temperature-humidity index). Rectal temperature (RT) and respiration rate (RR) were measured twice daily (0700 and 1500 h), whereas dry matter intake (DMI) was measured once daily (0800 h). In addition, blood samples (collected from the jugular vein) were analyzed for metabolites and CBC on days 7, 14, 21, and 28. Results: Relative to CON, BET supplementation was able to decrease RT on day 23 of the experiment (p = 0.04). Alternatively, RR was similar between the dietary treatments (p = 0.73). Feeding BET did not affect DMI compared with CON during HS conditions (p = 0.48). Furthermore, compared with CON, BET supplementation did not change leukocytes, neutrophils, lymphocytes, and hematocrit levels during HS conditions (p ≥ 0.17). However, a post hoc analysis indicated that hematocrit levels were decreased in BET-fed calves on day 7 of the study compared with CON calves during HS conditions (p = 0.05). Moreover, circulating glucose, albumin, and triglycerides were found to be similar between dietary treatments (p ≥ 0.55). Conclusion: BET supplementation slightly reduced RT and circulating hematocrit but did not affect other metrics in this HS experiment. More research into the effects of different doses of dietary BET on dairy heifer calves is needed.

The effects of Saccharomyces cerevisiae supplementation on intake, nutrient digestibility, and rumen fluid pH in Awassi female lambs.

AIM: The aim of this study was to evaluate the effect of feeding low (LO)- or high (HI)-fiber diets supplemented with Saccharomyces cerevisiae (SC) on nutrient intake, digestibility, nitrogen balance, rumen fluid pH, and serum concentrations of glucose and urea nitrogen in Awassi female lambs in a 2×2 factorial arrangement of treatments. MATERIALS AND METHODS: Experimental diets were as follows: (1) LO-fiber diet with no SC supplementation (-LO), (2) LO-fiber diet supplemented with SC (+LO), (3) HI-fiber diet with no SC supplementation (-HI), or (4) HI-fiber diet supplemented with SC (+HI). Eight female lambs were used in a replicated 4×4 Latin square design with 15-day experimental periods (10-day adaptation period and 5-day collection period). RESULTS: A fiber×SC interaction (p≤0.05) was detected for dry matter (DM) and crude protein (CP) intake among diets showing greater DM and CP intake for +LO diet compared to +HI group supplemented with SC, whereas -LO and -HI were intermediate. A fiber×SC interaction (p=0.05) was also detected for the neutral detergent fiber (NDF) intake among diets. Intake of NDF was greater for the -HI diet compared with +LO and -LO diets. Similarly, NDF intake was greater for +HI diet than -LO diet. A tendency (p=0.07) for a fiber×SC interaction was detected for acid detergent fiber (ADF) intake among diets as well. ADF intake tended to be greater for HI-fiber diets. No difference was observed in the rumen fluid pH for lambs fed with the different diets. No fiber×SC interactions were detected for the digestibility of DM, CP, NDF, and ADF among dietary treatments. Digestibility of DM was greater (72.9 g/100 g vs. 67.1 g/100 g; p=0.0002) for LO versus HI fiber. However, NDF and ADF digestibilities were greater (60.8 and 61.9 g/100 g vs. 55.8 and 52.7 g/100 g for NDF and ADF digestibility, respectively; p≤0.01) for the HI-fiber than the LO-fiber diets. CONCLUSION: Results obtained in the current study indicate that SC supplementation has a minimal effect on the performance of Awassi female lambs fed with varying fiber levels.

Effect of feeding calcium salts on performance of nursing Awassi ewes.

Twenty nursing Awassi ewes (BW = 50 ± 2.35 kg, age = 4.5 ± 1.2 years) with their lambs were used to evaluate the effects of feeding calcium salts in lactation diets on performance and pre-weaning growth of their lambs. Treatments were 0% calcium salts (CON) or 5% calcium salts (FAT). At the end of the study, a digestibility experiment was performed. Milk yield was greater (P < 0.05) for ewes fed the FAT diet than the CON diet. Milk composition was similar (P > 0.05) between diets. However, milk energy value (kcal/day) tended to be greater (P = 0.07) for the FAT diet than the CON diet. Concentrations of milk C18:1c9 and C20:0 were greater (P < 0.05) in ewes fed the FAT diet than the CON diet. However, concentration of trans-10, cis-12 CLA was lower (P = 0.05) in the FAT diet than in the CON diet. No differences in feed intake and body weight change were detected between diets. Digestibility of dry matter, organic matter, crude protein, ether extract, neutral detergent fiber, and acid detergent fiber were similar (P > 0.05) for diets. For lambs, weaning weight was not affected by treatments. However, average daily gain and total gain were greater (P = 0.053) for the FAT diet than the CON diet. Results suggest that supplementing lactating ewes with calcium salts at the beginning of lactation phase improves daily milk yield of ewes and pre-weaning growth of their lambs with no major negative impact on feed intake and digestibility.

Effect of bitter vetch (Vicia ervilia) seeds as a replacement protein source of soybean meal on performance and carcass characteristics of finishing Awassi lambs.

The objective of this study was to evaluate the effects of replacing the protein source of soybean meal (SBM) with different levels of bitter vetch seeds (BVS) in the diets of finishing Awassi ram lambs on performance, and carcass characteristics. Diets were designed based on replacing SBM with BVS as a percentage of the diet. Diets were: control (0% BVS), substituting 5% of SBM (5% BVS), 10% of SBM (10% BVS) and the entire SBM in the ration with BVS (15% BVS). Forty eight lambs (18.74 +/- 3.95 kg initial body weight and 70 days of age) were randomly assigned to 4 treatment diets (12 lambs/treatment). Lambs were given an adaptation period of 10 days and the experiment lasted for 84 days. At the end of the trial, a digestibility experiment was performed and 6 lambs from each treatment were slaughtered to evaluate carcass characteristics. Average daily gain tended (P = 0.07) to be higher for lambs fed 10% BVS when compared to the other diets. Neutral detergent fiber digestibility was higher (P < 0.01) in control diet compared to the other diets. Fat depth (C) and leg fat depth (L3) tended (0.05 < P < 0.1) to be affected by BVS levels in the diet. Leg total lean % was the highest (P < 0.05) in 5% BVS and 10% BVS diets. These results suggest that substituting SBM with BVS in the diets did not influence performance or carcass characteristics of lambs. However, the cost of ration formulation decreases since SBM is a very expensive component of the ration.