Dietary Effects on Ruminant Livestock Reproduction with Particular Reference to Protein

Potential benefits of amino acid supplementation for cervid performance and nutritional ecology, with special focus on lysine and methionine: A review

Deer farming is a thriving industry for venison, velvet antlers, trophy hunting, and other by-products. Feeding and nutrition are important factors for improving production performance, especially dietary protein and amino acids (AAs), as they are the main components of all tissues. Only a few studies on AA supplementation (Lys, Met, Arg) have been performed on cervids, which show positive effects on weight gain, ADG, feed-:gain ratio, plasma AAs, carcass weight, dressing percentage, yield of high-quality muscles, storage of internal fat during winter, DM and CP digestibility, plasma protein- and fat-related metabolite concentrations, antler burr perimeter, weight, length and mineralisation, velvet antler yield, rumen volatile fatty acids, and microbiome composition. All these effects are relevant for supporting the production of cervids products, from venison to velvet or trophy antlers, as well as their general performance and well-being of captive-bred cervids. The current available information suggests that AA supplementation can be especially interesting for animals fed low protein rations, and growing animals, but should be avoided in high rations and during winter, since it may promote the accumulation of internal fat. Potential effects on milk production and the concentrations of different hormones involved in the regulation of the antler cycle should be further explored.

Flooding on Beef and Swine Farms: A Scoping Review of Effects in the Midwestern United States

BACKGROUND

Increasing uncertainty and variability in weather due to climate change puts enormous stress on the sustainability of agricultural communities in several parts of the continental United States. Rural agriculture-based communities, such as those in North Carolina, Nebraska, and Illinois are particularly vulnerable to the impacts of flooding. These extreme weather events affect many animal facilities, and flooding can cause long-term impacts on animal health and productivity.

OBJECTIVES

This scoping review investigated the potential short- and long-term ramifications of flooding on beef cattle and swine farms with theoretical locations in the Midwestern U.S. The goal of this review is to create a concept map to identify research gaps related to efforts to support those animals and peoples ravaged by floods. This was accomplished by performing a scoping review using search terms "beef OR swine AND flood" to assess direct effects and then "beef OR swine AND direct effect" to evaluate secondary and tertiary effects.

RESULTS

Our findings were based on a total of 89 peer-reviewed publications, with 50 publications relating to beef cattle, 24 relating to swine, and 15 containing information applicable to both. On beef farms, the effects of flooding can be broad and long-lasting. The short-term risks of flooding are reasonably well-understood, including the comingling of unfamiliar cattle, nutritional restriction, and disease transmission. However, long-term impacts, including potential effects on reproduction, nutrition, and carcass quality, have been less studied. In particular, further research is needed on mold species that contaminate hay post-flood, the effect of moldy hay ingestion on cattle, and the effects of heavy metal consumption on cattle and consumers. Little research is available regarding the effects of flooding on swine farms, likely due to the highly intensive nature of swine operations. In general, swine farms suffer from acute infectious diseases and biosecurity risks after flooding events.

CONCLUSIONS

The potential ramifications of flooding on livestock farms differ among farm operations. Beef farms should prepare for long-term impacts on nutrition and reproduction, while swine farms should prepare for short-term impacts on biosecurity.

Alpaca semen quality in relation to different diets

The aim of the present study was to evaluate the biochemical composition of seminal plasma, along with semen quality, of alpacas maintained on different diets (hay; hay+pasture grazing; pasture grazing+sheep concentrate; pasture grazing+horse concentrate; Periods 1-4, respectively). Alpacas (n=5) were fed the four different diets for a period of 6 weeks each. During the period of feeding of each diet, semen was collected using an artificial vagina to determine its volume, viscosity, sperm concentration and sperm motility. Moreover, testicular volume and body condition score were evaluated. Seminal plasma was analysed biochemically to measure total protein, triglyceride, cholesterol, γ-glutamyl transferase, alanine aminotransferase (ALT) and alkaline phosphatase levels. Protein profiles were investigated using one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. There was high variability in semen parameters between different males maintained on the same diet. Semen volume increased significantly (P<0.05) when alpacas were fed diets containing commercial sheep and horse concentrates. In contrast, sperm concentration and motility decreased significantly (P<0.05) from Period 1 to Period 4. Dietary changes had no effect on viscosity. Significant reductions were seen in triglyceride and cholesterol content, as well as γ-glutamyl transferase, ALT and alkaline phosphatase concentrations, from Period 1 to Period 4. Regardless of experimental period, a wide variation was seen in seminal plasma enzyme concentrations between alpacas, whereas diet had no effect on glucose and total protein concentrations in the seminal plasma. Eight protein bands, with molecular weights ranging from 200 to 14kDa, were considered in electrophoresis gel after image analysis. Proteins fractions of the 14-kDa (total protein express in mddL(-1) with a molecular weight of 14-kDa, TP8) and 21-kDa (total protein express in mddL(-1) with a molecular weight of 21-kDa, TP7) bands were not present in all samples of alpaca seminal plasma. There were no significant changes in the concentration of any protein fractions during the four periods. Moreover, the protein fraction of the 60-kDa (total protein express in mddL(-1) with a molecular weight of 60-kDa, TP3) band was the most prevalent in all periods. These results demonstrate that there are marked changes in semen quality, as well as some parameters related to the composition of alpaca seminal plasma, that are dependent on diet, which may indicate the need for specific diet formulation to improve reproductive performance. We hypothesise that, in alpacas, the mechanisms underlying the changes in some reproductive traits in response to feeding regimens could be related to changes in the endocrine-gonadal system.

Effect of feed intake restriction on reproductive performance and pregnancy rate in Egyptian buffalo heifers

The objective of the present experiment is to study the effect of feed intake restriction on the reproductive performance and pregnancy rate in Egyptian buffalo heifers. Thirty anestrus buffalo heifers were randomly divided into two equal groups. The low feed intake (LFI, n=15, 50 % restriction) group was fed a diet that consists of 3 kg concentrate, 1 kg wheat straw, and 3 kg fresh alfalfa, while the high feed intake (HFI, n=15) group was fed double the amount given to the LFI group for 4 months. All animals were weighed, transrectally examined, and visually checked for the signs of estrus, and blood samples were collected. Heifers in heat were mated with one fertile bull. The number of heifers showing estrus activity was 93.3 % in HFI vs. 20 % in LFI (P<0.01). Ovarian activity started earlier (P=0.03) in the HFI than LFI group. The weight at breeding, the diameter of the dominant follicle, number of heifers showing ovulations, number of services per conception, pregnancy rate, and overall mean of progesterone and estrogen concentrations were significantly higher (P<0.01) in the HFI than in the LFI group. The level of serum total protein, albumin, globulin, glucose, total cholesterol, and calcium were significantly higher (P<0.05) in the HFI group. Restriction of the daily feed intake to 50 % from NRC recommendations impair reproductive performance in terms of increasing the age at first service and reducing the pregnancy rate in buffalo heifers. In conclusion, feed intake could be effective in improvement of reproductive performance in buffalo heifers and further studies should be done on large scale of buffaloes in this point.

The effect of dietary protein restriction on the secretion of LH and FSH in pre-pubertal female lambs

The effect of restricted dietary protein on the synthesis, storage and release of LH and FSH was studied in pre-pubertal female lambs. The experiment started when the lambs were aged 12 weeks and weighed 26.0+/-1.6 kg. It was conducted for 25 weeks. The lambs were fed isocaloric diets containing either a restricted level of crude protein (8% CP; n=6; treatment R) or an elevated one (18% CP; n=4; treatment E). At 37 weeks of age and before the first oestrous cycle, blood samples were collected over 6 h at 10 min intervals for LH assay. The lambs were slaughtered and their brains recovered and fixed in situ. Immuno-reactive (IR) LH and FSH cells were localised by immunohistochemistry techniques. Messenger RNA analyses used by non-isotope in situ hybridisation with sense and anti-sense riboprobes from beta subunits of LH and FSH cDNA clones. Data were generated using computer analysis to measure the proportion of IR and/or hybridising cells and their optical density for immuno-staining and hybridisation signal. Plasma LH was measured by RIA. The daily live-weight gains were 56.5+/-13.1 g and 97.8+/-14.3 g for R and E lambs, respectively (P<0.05), so that final weights at slaughter were 36.1+/-1.97 kg and 39.1+/-3.44 kg, respectively (P<0.05). The number of cells expressing LH beta mRNA and the optical density of this hybridisation signal was significantly (P<0.001) lower in the R lambs but the number of IR LH positive cells was higher (P<0.001) than for the E lambs. The concentration of LH in the plasma of R sheep was lower (P<0.05) than the E group and this response was associated with a decrease (P<0.05) in LH pulse frequency and amplitude. Dietary protein concentration appeared to have no effect on the IR in FSH cells or on the expression of FSH beta mRNA. In summary, the low protein diet influenced the body weight and weight gain of growing lambs and exerted an inhibitory effect on the synthesis and the release of LH in the pituitary gonadotrophs. No such effect was observed for FSH. It was concluded that the protein concentration of the diet consumed during the growth of female lambs may be an important modulator of processes leading to the pre-pubertal rise in LH.

Supplementation to meet metabolizable protein requirements of primiparous beef heifers: I. Performance, forage intake, and nutrient balance

Three experiments were conducted to evaluate the response of supplementing primiparous heifers based on the metabolizable protein (MP) system during pregnancy and lactation. In Exp. 1, 12 pregnant, March-calving heifers (432 +/- 10 kg) grazing Sandhills range were randomly allotted to one of two treatments: supplementation based on either the MP system (MPR) or the CP system (CPR). Supplements were fed to individual heifers from October to February and no hay was offered. Grazed forage organic matter intake (FOMI) was measured in November, January, and February. In Exp. 2, 18 heifers (424 +/- 8 kg) were randomly allotted to one of three treatments: 1) supplementation based on the MP system with hay fed in January and February (average 2.0 kg/d; MPR/hay), 2) supplementation based on the CP system, with hay fed in January and February (CPR/hay), or 3) supplementation based on the MP system, with no hay fed (MPR/no hay). Supplements were fed from October to February, and FOMI was measured in December and February. In Exp. 3, lactating 2-yr-old cows (394 +/- 7 kg) maintained on meadow hay were supplemented to meet either 1) MP requirements (LMPR) or 2) degradable intake protein requirements (LDIPR). Body weight (BW) and body condition score change, hay intake, and milk production were measured. In Exp. 1, grazed FOMI decreased (P = 0.0001) from 1.9% of BW in November to 1.2% in February, but no differences among treatments were detected for FOMI or BW change. In Exp. 2, grazed FOMI declined (P = 0.0001) from 1.7% of BW in December to 1.1% in February, with no differences among treatments. Heifers on the MPR/hay and CPR/hay treatments had higher (P = 0.0018) total intake (grazed forage + hay intake) in February (1.7% BW) than the MPR/no hay heifers (1.1% BW). Heifers on the MPR/no hay treatment had a lower weight (P = 0.02) and tended (P = 0.11) to have a lower BCS than heifers on other treatments. In Exp. 3, the LMPR cows had higher (P = 0.02) ADG than LDIPR cows (0.41 and 0.14, respectively), but treatment did not affect milk production. Organic matter hay intake averaged 2.4% of BW. We conclude that supplementation to meet MP requirements had little benefit to heifer performance during gestation, but increased weight change during lactation. Because grazed forage intake decreased from 1.9 to 1.1% of BW with advancing gestation, supplemental energy is necessary to reduce weight and condition loss of gestating hefiers grazing dormant Sandhills range.

Using milk urea nitrogen to predict nitrogen excretion and utilization efficiency in lactating dairy cows

Because animal agriculture has been identified as a major source of nonpoint N pollution, ways to reduce the excretion of N by production animals must be examined. The objective of this research was to develop and evaluate a mathematical model that integrates milk urea N to predict excretion, intake, and utilization efficiency of N in lactating dairy cows. Three separate digestibility and N balance studies (10 diets, 40 cows, and 70 observations) were used to develop the model, and 19 independent studies (93 diets) were used for evaluation. The driving variables for the model were milk urea N (milligrams per deciliter), milk production (kilograms per day), milk protein (percentage), and dietary crude protein (percentage). For the developmental data set, the model accurately predicted N excretion and efficiency with no significant mean or linear bias for most predictions. Residual analysis revealed that a majority of the unexplained model error was associated with variation among cows. For the independent data set, model prediction error was approximately 15% of mean predictions. A mean of at least 10 cows was determined to be appropriate for model predictions. Target milk urea N concentrations were determined from expected urinary N excretion for cows that were fed according to National Research Council recommendations. Target values calculated in this manner were 10 to 16 mg/dl, depending on milk production. Milk urea N is a simple and noninvasive measurement that can be used to monitor N excretion from lactating dairy cows.