Modelling THI effects on milk production and lactation curve parameters of Holstein dairy cows.

The main objective of this study was to determine the potential impact of heat stress (HS) on milk production and lactation curve parameters of Holstein dairy cows. Milk, fat, protein, and somatic cell count test-day records collected between 2013 and 2019 from 947 cows in 23 herds were combined with THI calculated from meteorological data recorded between 2013 and 2019. The temperature-humidity index (THI) was used to investigate the effect of heat stress. The severity of heat stress was measured using the temperature-humidity index (THI) and the impacts of different THIs-low (≤68), moderate (68-72), and high (≥72) on production performance and lactation curve parameters were measured. The nonlinear model of Wood was applied for modeling the lactation curve. Analysis of variance was applied to test the effects of three levels of THI on milk production, its composition, and lactation curve parameters. Results showed losses due to heat stress. A decrease in milk yield and fat and protein content was reported. Fat and protein contents tended to decrease steadily with increasing values of THI. Milk yield ranged from 17.882±0.064 (6872), fat and protein contents ranged from 3.551 ±0.041 to 3.449 ±0.026 and from 3.246 ±0.031%, to 3.113 (0.029) for 6872, respectively. Somatic cell score was marked by an increase (from 4.143 to 4.358) at the highest ranges of THI>72 and decreased values (from 4.143 to 3.857) at the lowest ranges of THI. Heat stress showed a significant effect on the parameters of the lactation curve. The increased value of THI showed a significant effect on milk yield THI was in a significant negative correlation with the yield, and quality of milk. The effect of THI was highly significant (P < 0.05) for all parameters of the lactation curve and milk yield. Cows exposed to THI between 68 and 72 achieved the highest peak milk yields and the highest total yield of 305 days of lactation (Y305).

A proposal of linear assessment scheme for the udder of dairy camels (Camelus dromedarius L.).

Digital images from the left side of the mammary gland of 146 multiparous lactating dromedary camels in mid lactation and managed under intensive conditions were obtained immediately before milking and used to build up a reference scheme for the morphological evaluation of camel mammary glands. A 5-point linear scoring scheme (with 0.5-point accuracy) was subsequently generated based on five mammary traits (udder, depth and floor inclination, teats, shape, length, and width). Results showed that Arabian dairy camels had voluminous udders with large-sized teats. Most common udder shape was globular (47.3 %), followed by the pear (34.3 %) and pendulous (18.4 %) shapes. Conical- or funnel-shaped teats (60.9 %) were the most frequent, followed by cylindrical- (29.5 %) and blew-up (9.6 %)-shaped teats. The observed variation in the udder and teat measurements, as well as in typology, attested that dromedary camels need especially large milking clusters to improve their machine milkability. Assessment of the previously indicated digital images according to the proposed linear scoring scheme, performed by 3 independent operators showed that the overall means were close to 3.00 points (values between 2.45 and 3.62), and the standard deviations were close to 0.76 points (values between 0.58 and 0.94). Moderate repeatability between operators (r > 0.69) was obtained for udder depth and floor inclination, indicating that training of operators, as well as improvements in the definition of traits should be considered in future studies. Further research is needed to validate the proposed linear scoring system in different stages of lactation and parities using a large number of camels.

Feasibility of utilising an infrared-thermographic technique for early detection of subclinical mastitis in dairy camels (Camelus dromedarius).

Despite the proven ability of infrared thermography (IRT) technology for early detection of subclinical mastitis in dairy cows/sheep/goats, studies on its diagnostic feasibility in dairy camels are lacking. Sixty-five lactating camels in mid lactation, machine milked twice-daily and managed under intensive conditions were screened to evaluate the feasibility of utilising IRT compared with other routine indicators in detecting subclinical mastitis. Immediately before the morning milking, a portable infrared camera was used to obtain thermograms in duplicate for the front and rear left quarters to determine the udder surface temperature (UST). Thereafter, milk samples from quarters were collected, and processed for California mastitis test (CMT) score and somatic cell count (SCC). In the present study, CMT score was used to define subclinical mastitis and the feasibility of IRT to detect subclinical mastitis was compared with CMT and SCC. According to CMT score, subclinical mastitic udders had an average UST of 1·42 °C greater (P<0·0001) than healthy udders. The relationship between UST and CMT was found to be highly correlated (r=0·77; P<0·001), and UST was linearly increased as the CMT increased [UST (°C)=34·86+0·66×CMT score; R 2=0·65; P<0·001]. Additionally, high correlations were obtained between UST and SCC score (r=0·75; P<0·001) and the relationship between UST and SCC was fitted best to a logarithmic equation [UST, °C=33·39+0·88×Log (SCC, ×103 cells/ml), R 2=0·61, P<0·001]. The cut-off value, sensitivity, specificity and area under the receiver operating characteristics (ROC) curve for UST were 35·15 °C, 0·90, 0·98, and 0·95, respectively, when subclinical mastitis was defined according to CMT score, and were 35·70 °C, 0·89, 0·96 and 0·94, respectively, when categorised according to the obtained SCC threshold (SCC=432 000 cells/ml). In conclusion, IRT, as an indirect non-invasive screening method, was highly feasible for distinguishing subclinical mastitic udders in dairy camels, which is crucial to treat mastitis early and efficiently.

Identification of Genetic Polymorphisms of PI, PIII, and Exon 53 in the Acetyl-CoA Carboxylase-α (ACACα) Gene and Their Association with Milk Composition Traits of Najdi Sheep.

Recently, increasing attention has been paid to sheep milk products, which are high in saturated fatty acids (SFA), and the extent of their impact on human health. This study aimed to identify SNPs for PI, PIII, and Exon 53 in the ACACα gene and their association with the MC and FA profiles in Najdi sheep milk. A total of 76 multiparous Najdi ewes were used, and they were maintained using the same feeding system. Milk and blood samples were collected during the first lactation. A genetic polymorphism analysis identified 20 SNPs: 4 SNPs on PI, 6 SNPs on PIII, and 10 SNPs on Exon 53. In PI, the SNP g.4412G > A was associated (p < 0.05) with palmitic acid (C16:0), palmitoleic acid (16:1 n-7) and linoleic acid (LA), while SNP g.4485C > G was associated with CLA and vaccenic acid (VA) (p < 0.05). Furthermore, in PIII, two SNPs (g.1168A > G and g.1331G > T) were associated with milk protein (p < 0.05), while the SNP g.6860G > C in Exon 53 was associated with milk fat (p < 0.05). SNPs in the Najdi breed have been shown to be strongly related to milk fat and EFA contents. This could support a genetic selection program and the control of milk traits in the Najdi breed of high-quality dairy sheep.

Heavy Metals Levels in Soil, Water and Feed and Relation to Slaughtered Camels' Tissues (Camelus dromedarius) from Five Districts in Saudi Arabia during Spring.

Soil, water, and forage contaminated with toxic heavy metals such as Pb, Cd, and Co can affect the meat and liver quality of camels raised in this area which affect human health. This study aimed to determine the concentrations of Pb, Cd and Co in soil, water, feed and young camels' carcass tissues (meat, liver, whole blood, rumen fluid and rumen tissue) from five districts in Saudi Arabia during the spring. All samples were wet-digested and analyzed by ICP-OES for heavy metals. In the liver, a significantly higher (p < 0.05) concentration of Pb and Co was observed in camels reared in the central and southern districts, while Cd was found significantly higher in the western and northern districts. The concentration of Pb, Cd and Co in meat of camels in the northern district was significantly higher (p < 0.05), and the meat of camels in the west had a higher (p < 0.05) concentration of Co. In addition, the Cd and Co concentrations in rumen fluid samples from camels in the eastern district were significantly higher than in the central district. A negative correlation between the concentration of Pb and Cd in rumen fluid and rumen tissue was reported. The accumulation of Cd, Pb, and Co in meat and liver was below the recommended maximum limit. Therefore, the harmful risk of human consumption of camel meat and liver is not possible.

Blue-green algae (Arthrospira platensis) as an ingredient in pasta: free radical scavenging activity, sensory and cooking characteristics evaluation.

The effects of semolina enrichment with blue-green algae (Arthrospira platensis) at three different levels (1, 2 and 3 g/100 g of semolina) on the colour, cooking properties, firmness, free radical scavenging activity and sensory characteristics of pasta are reported. Microalgae addition resulted in higher swelling index and lower cooking loss than the control sample. A significant increase in pasta firmness was evidenced with an increase of added microalgae due to structural reinforcement. In addition to colouring, the use of A. platensis (2 g/100 g of semolina) can enhance the sensory quality and nutraceutical potential as evaluated by free radical scavenging activity of pasta.

Factors influencing the prevalence of subclinical mastitis in lactating dromedary camels in Riyadh Region, Saudi Arabia.

The purpose of this study was to determine the prevalence of subclinical mastitis in camels in Riyadh, Saudi Arabia and the factors influencing its incidence. A total of 740 quarter milk samples were collected from 47 camel herds belonging to Majahim, Maghatir, Shu'l, and Sufer breeds. California mastitis test (CMT) was used as a screening test for subclinical mastitis. Samples giving negative or trace CMT scores (0) were assigned to healthy quarters, while those giving positive scores of 1+ to 3+ were assigned to subclinically affected quarters. Logistic regression was used to assess the association of breed, parity, and stage of lactation with the prevalence of subclinical mastitis. Milk fat, protein, lactose, solid nonfat percentages and Na, Ca, and K concentrations were compared in CMT-positive versus healthy quarters. One third (33%) of tested quarters had subclinical mastitis based on CMT. The estimated probability of subclinical mastitis with the combined effects of breed, parity, and stage of lactation ranged from 15.8% to 54.6%. The risk of subclinical mastitis increased significantly with parity and with the early stage of lactation. The Shu'l breed had significantly higher prevalence of subclinical mastitis than other breeds. Significant decreases in protein, lactose, and solid nonfat, Ca and K concentrations and increase in Na concentrations were associated with subclinical mastitis. In conclusion, subclinical mastitis is prevalent in Saudi camels, and its incidence is influenced by breed, parity, and stage of lactation.

Assessment of Meat-Type Sheep Welfare Using Animal-Based Measures.

This study aimed to assess the welfare of Tunisian sheep in extensive sheep production systems using animal-based measures of ewe welfare. This study encompasses the first national survey of sheep welfare in which animal-based outcomes were tested. Animal-based welfare measures were derived from previous welfare protocols. Fifty-two Tunisian farms were studied and a number from 20 to 100 animals by flock were examinated. The whole flock was also observed to detect clinical diseases, lameness, and coughing. The human-animal relationship was selected as welfare indicators. It was evaluated through the avoidance distance test. The average avoidance distance was 10.47 ± 1.23 and 8.12 ± 0.97 m for a novel person and farmer, respectively. The global mean of body condition score (BCS) was 2.4 with 47% of ewes having a BCS of two, which may be associated with an increased risk of nutritional stress, disease, and low productivity. Ten farms had more than 7% of lambs with a low body condition score, which may be an indication of a welfare problem. The results obtained in the present study suggest that the used animal-based measures were the most reliable indicators that can be included in welfare protocols for extensive sheep production systems.

Effects of Roughage Quality and Particle Size on Rumen Parameters and Fatty Acid Profiles of Longissimus Dorsi Fat of Lambs Fed Complete Feed.

The fatty acid composition for the longissimus dorsi (LD) fat of carcass sheep is a crucial factor impacting meat quality. We performed a 90-day feeding trial of 25 Naemi lambs to investigate the effects of roughage sources (alfalfa or wheat straw) of two sizes (regular and 1 cm chopped) when fed with pelleted total mixed ration (TMR) on the growth performance, fermentation patterns, and fatty acid (FA) composition of longissimus dorsi (LD) fat. Lambs were randomly assigned to individual pens with five treatment diets, as follows: C, control group with TMR; T1, TMR and regular alfalfa hay; T2, TMR and alfalfa hay chopped to 1 cm; T3, TMR and regular wheat straw; and T4, TMR and wheat straw chopped to 1 cm. Four lambs were randomly selected from each treatment (20 total) and sacrificed. LD fat of the carcass was extracted and analyzed for FA using a gas chromatography-mass spectrometry. Significantly increased feed intake was found in T1 and T2. The FA composition of LD fat in T2 had higher unsaturated fatty acid (UFA), omega-6 (n6), and omega-3 (n3) FA content. Conjugated linoleic acid (CLA) and α-linoleic acid were highest in lambs fed T1 and T2. Feeding different types of roughage, especially alfalfa hay, either regular or chopped, with total pelleted mixed ration is crucial to improving feed intake and body weight gain, as it positively enhances the rumen microbial fermentation process by controlling rumen pH. The FA profiles of meat from lambs fed TMR with regular or 1 cm particle size alfalfa hay (T1 and T2) are recommended for human consumption as a source of healthy FAs.

The relationships between body fatness, leptin, testosterone, and reproductive performance in ram lambs as affected by level and frequency of feeding.

This study was carried out using 24 Najdi ram lambs of approximately 6.5 months old to evaluate the effects of feed restriction and frequency of feeding on hormone concentrations of leptin and testosterone, sexual behavior, and semen traits. Ram lambs were allotted equally into three feeding groups. The first group was used as a control and fed ad libitum. The second and third groups were restricted fed at 0.85 ad libitum and fed either once (R1M) or twice daily (R2M). Sexual behavior and semen evaluation were assessed during the sixth, seventh, and eighth weeks of the study. Blood samples were drawn at 1-hour pre-feeding on days 41, 48, and 55 of the study for the determination of serum leptin and testosterone concentrations. All lambs were slaughtered after 8 weeks of experimentation. Results showed that the restricted-fed groups had lower (P < 0.01) values for slaughter body weight, average daily gain, dry matter intake, internal fat, tail fat, body fat thickness, body wall thickness, and testes weight than the ad libitum group; these corresponding traits did not differ between both restricted-fed treatments. Leptin and testosterone concentrations in restricted-fed rams were (P < 0.01) lower and higher, respectively, than in the ad libitum rams; there were no differences between R1M and R2M groups. The restricted-fed rams had lower (P < 0.01) ejaculation latency time compared with control, whereas the percentage of sexually active rams and sexual desire score were not affected by feeding restriction or frequency of feeding. Sperm motility, progressive motility, and percentage of sperm moving at rapid speed were higher (P < 0.01) in feed-restricted rams than in the ad libitum rams. R1M rams had higher (P < 0.01) value for straightness and lower (P < 0.01) value for curvilinear velocity in comparison with the ad libitum group. Testosterone was correlated positively (P < 0.05) with sperm motility and progressive motility and negatively (P < 0.04) with fat measurements, leptin, and ejaculation latency time. In conclusion, moderate intake restriction can optimize body fatness and testosterone concentrations in rams, which helped to improve some reproductive traits.

Use of ultrasonography to estimate cistern size and milk storage at different milking intervals in the udder of dairy cows.

Four lactating Holstein cows (average milk yield: 20 +/- 3 l/d) were used to develop and validate a method for estimating the size of udder cisterns (Sinus lactiferi) using ultrasonography. A sectorial transducer probe of 5 MHz, placed in contact with the teat in a parallel cranial position, was used to obtain vertical scans of the udder in two perpendicular planes with the teat canal axis as reference. Udder scans for each udder quarter were taken randomly at intervals of 4, 8, 12, 16, 20 and 24 h after milking. Glandular parenchyma (echogenic) and lumen of the cisterns full of milk (anechogenic) were evident in the scans, the calculated area of the anechogenic portion being defined as cistern area. Cistern areas measured in perpendicular scans were highly correlated. Immediately after each measurement, cisternal milk was removed from each quarter using a teat cannula after i.v. injection of an oxytocin-receptor blocking agent. Alveolar milk from each quarter was then obtained by machine milking after i.m. injection of oxytocin. Cistern area and cisternal milk volume increased with length of milking interval showing a curvi-linear pattern with a plateau after 16 h. Correlations between cistern area and cisternal milk volume were positive and significant (P<0.001) at all intervals but showed the highest values with the smallest residual standard deviations at 8 h (r=0.88) and 12 h (r=0.84). Since 8 h has previously been identified as a suitable time at which to determine cisternal milk volume for the purposes of defining suitability for different milking strategies, we conclude that ultrasonography provides a satisfactory, non-invasive method for determination of milk storage characteristics in dairy cows.

Effect of different milking intervals on the composition of cisternal and alveolar milk in dairy cows.

Effects of six different milking intervals on the distribution of milk between cistern and alveoli were studied in a randomized, incomplete Latin Square experiment with four lactating Holstein cows. Cisternal and alveolar milk was measured by udder quarter at 4, 8, 12, 16, 20 and 24-h intervals with a 3-d interperiod of regular milking. Cisternal milk was evacuated using a cannula after injection of an oxytocin-receptor blocking agent, followed by an injection of oxytocin to remove the alveolar fraction. Milk samples from each fraction and quarter were collected for analysis. Cisternal and alveolar milk increased with milking interval and represented on average 30 and 70% of the milk stored in the udder, respectively. Fat content in alveolar milk remained constant during the first 16 h, increasing rapidly thereafter, reaching its maximum at 24 h (6.95%). Fat content in cisternal milk decreased with milking interval and reached its minimum at 24 h (0.96%). Total fat yield tended to increase for cisternal milk with longer milking intervals, but it increased markedly for alveolar milk, showing that fat globules did not pass freely from alveoli to cistern between milkings. Milk protein content was greater in rear quarters than in front quarters for both milk fractions. Milk protein content increased in the cisternal milk fraction and tended to increase in the alveolar milk fraction with longer milking intervals, but values did not differ between cisternal and alveolar fractions or between front and rear quarters. Total protein yield increased with milking interval in both fractions, indicating that casein micelles passed more freely than fat globules from the alveolar to the cisternal compartment. In conclusion, the short-term effects of milking intervals in milk composition were explained by the changes observed in alveolar and cisternal milk ratio.