2 Contribution Number 1328-E from the Agricultural Research Organization, The Volcani Center

ABSTRACT We studied the balance of Na + , K + , Cl -, and water in six high yielding (>39 kg/d of milk) cows between wk 2 to 1 prepartum and at 2 and 7 wk postpartum during winter in Israel. Cows were fed complete diets; Na + and Cl -contents exceeded dietary recommendations, and K + content was equal to dietary recommendations. Milk yield was related positively and significantly to retention of Cl -and K + , indicating that ions that are the main constituents of sweat can limit the ability of cows to express full genetic potential. The highest ion retention was recorded for cows that had the highest dry matter intake and, hence, the highest ion intake. Retention of Cl -was highest for cows that were most efficient in retaining Cl -in the kidney. In hot climates, increasing the concentrations of ions in the diet of early lactation cows according to the actual dry matter intake could prevent or reduce the severity of ion deficiencies. Water turnover rate of the cows was dependent on dry matter intake, milk yield, and respiratory-cutaneous water loss. The milk-free water balance (water turnover rate minus water secreted in milk) could be very efficiently predicted for lactating and nonlactating cows by the following equation: milk-free water balance (kilograms per day) = digestible energy intake (megacalories per day) × 0.58 + respiratory-cutaneous loss (kilograms per day) × 0.97 ( n = 18; R 2 = 0.97). This formula provides a tool to assess the evaporative-cutaneous water loss from feed and water intake measurements to evaluate the severity of heat stress. ( Key words: water, ions, metabolism, lactation) Abbreviation key: FWI = free water intake, MFWB = milk-free water balance, RCW = respiratorycutaneous water, WTO = water turnover

The effects of tannin-containing ground pine bark diet upon nutrient digestion, nitrogen balance, and mineral retention in meat goats

Background Pine bark is a rich source of phytochemical compounds including tannins, phenolic acids, anthocyanins, and fatty acids. These phytochemicals have potential to significantly impact on animal health and animal production. The goal of this work is to measure the effects of tannins in ground pine bark as a partial feed replacement on feed intake, dietary apparent digestibility, nitrogen balance, and mineral retention in meat goats. Results Eighteen Kiko cross goats (initial BW = 31.8 ± 1.49 kg) were randomly assigned to three treatment groups (n = 6). Dietary treatments were tested: control (0 % pine bark powder (PB) and 30 % wheat straw (WS)); 15 % PB and 15 % WS, and 30 % PB and 0 % WS. Although dry matter (DM) intake and digestibility were not affected (P > 0.10) by feeding PB, neutral detergent fiber (linear; P = 0.01), acid detergent fiber (linear; P = 0.001) and lignin digestibility (linear; P = 0.01) decreased, and crude protein (CP) digestibility tended to decrease (P = 0.09) as PB increased in the diet, apparent retention of Ca (P = 0.09), P (P = 0.03), Mg (P = 0.01), Mn (P = 0.01), Zn (P = 0.01) and Fe (P = 0.09) also increased linearly. Nitrogen intake and fecal N excretion were not affected (P > 0.05) by addition of PB in the diet, but N balance in the body was quadratically increased (P < 0.01) in the 15 % PB diet compared to other diets. This may be due to more rumen escape protein and less excreted N in the urine with the 15 % PB diet. The study showed that a moderate level of tannin-containing pine bark supplementation could improve gastrointestinal nitrogen balance with the aim of improving animal performance. Conclusion These results suggest that tannin-containing PB has negative impact on fiber, lignin, and protein digestibility, but positively impacted on N-balance

Milk yield estimation during suckling using the double oxytocin injection-milking and the double weighing-suckling methods in dairy goats

The aim was to verify the validity of the double oxytocin-milking (DOT) method as milk yield estimator during the suckling period of lactating dairy goats. To this end, it was necessary to determine whether the weighing suckling weighing (WSW) and DOT methods of milk yield estimation satisfied the criteria to be considered valuable, the accuracy between both methods and the suitability of DOT to evaluate actual milk. At parturition, sixty lactating Murciano Granadina breed goats were separated into 2 groups, in mixed (MS; n = 24) and artificial rearing (ARS; n = 36) management systems. Until the sixth week of lactation (weaning), MS goats suckled one kid while kids from ARS goats were artificially reared; moreover, goats in both systems were submitted to once-a-day milking. Once per week, actual milk yield for ARS goats and potential milk yield were recorded using DOT method for all goats, except for 12 goats in ARS which remained as a control. Twelve goats from each management system were used to evaluate diurnal variation in milk production (DVM) by DOT method for 6 consecutive days in week 4 of lactation. No difference in DVM was found by DOT method in 4-h milk production of goats in MS (P = 0.099) or ARS (P = 0.220), which allowed sixfold multiplication of milked milk volume to obtain potential milk per day. ARS goats subjected to a weekly DOT and control group goats showed a similar (P = 0.379) lactation curve for the first 6 weeks of lactation. The DOT method slightly overestimated (3.4%, P = 0.005) the milk yield evaluated by WSW method for goats under an MS, but fitted the actual milk obtained by common milk records for the group of goats in an ARS submitted to the DVM test (P = 0.357) and the group in ARS alone (P = 0.163). The DOT method applied for 8 consecutive days led to a drop of 6 12% in milk yield during the following week for both production systems. In conclusion, DOT was an accurate method to estimate milk yield during the first weeks of lactation both in MS and ARS under the conditions of this experiment. © 2013 Elsevier B.V. All rights reserved.Fernández Martínez, N.; Balasch Parisi, S.; Pérez Baena, I.; Rodríguez Garcia, M.; Peris Ribera, CJ. (2013). Milk yield estimation during suckling using the double oxytocin injection-milking and the double weighing-suckling methods in dairy goats. Small Ruminant Research. 112(1-3):181-185. doi:10.1016/j.smallrumres.2012.12.023S1811851121-

Effects of frequent machine milking and suckling in early lactation on blood plasma ion homoeostasis in high-yielding dairy cows

SUMMARY Groups of nine or ten cows were assigned, after calving, to treatments in which they were (i) machine milked three times daily (M3), (ii) machine milked six times daily (M6) or (iii) suckled three times daily in addition to being machine milked three times daily (S). Treatments were administered during the first 6 weeks postpartum. On one day, at weeks 1 and 6 postpartum, blood samples were collected from all cows at 30-min intervals between 06.00 and 13.00 h and these were analysed for plasma osmolality and plasma concentrations of Na + , K + and Cl − . Milk yield was significantly higher in suckled cows than in cows milked six times daily, but significantly lower in cows milked three times daily. In cows milked six times daily, and to a greater extent in suckled cows, there was a reduction in plasma osmolality and monovalent ion concentrations (Na + , K + and Cl − ), which could increase the susceptibility of the cows to water intoxication. Moreover, suckling or milking the cows six times daily was associated with increased fluctuations in plasma osmolality and plasma Cl − concentrations. The decrease in plasma osmolality and ion concentration and the increased variation in plasma osmolality and Cl − were probably related to increased water intake and may be indicative of a severe challenge to homoeostasis regulation

Investigation of relationship between vitamin D status and reproductive fitness in Scottish hill sheep

There is a growing interest in the influence of vitamin D on ovine non-skeletal health. The aim of this study was to explore the relationship between pre-mating vitamin D status, as assessed by serum concentrations of 25-Hydroxyvitamin D [25(OH)D; comprising D2 and D3] and subsequent reproductive performance of genetically unimproved Scottish Blackface (UBF), genetically improved Scottish Blackface (IBF) and Lleyn ewes kept under Scottish hill conditions. 25-Hydroxyvitamin D2 (25(OH)D2) and 25-Hydroxyvitamin D3 (25(OH)D3) concentrations were determined in serum samples harvested in November from ewes grazed outdoors. There were no significant differences in 25(OH)D2concentrations amongst the 3 genotypes. Lleyn ewes had significantly higher 25(OH)D3 and 25(OH)D concentrations than both Scottish Blackface ewe genotypes, whereas these vitamin D parameters did not differ significantly between the UBF and IBF ewes. Concentrations of 25(OH)D3 and 25(OH)D were positively associated with subsequent birth weights of singleton and of twin lamb litters. No significant associations between vitamin D status and number of lambs born or weaned per ewe were found. This study demonstrates that concentrations of cutaneously-derived 25(OH)D3, but not of orally consumed 25(OH)D2, differed between breeds. The positive association between ewe vitamin D status and offspring birth weight highlights the need for further investigations

Transcriptomic profiles of muscle, heart, and spleen in reaction to circadian heat stress in Ethiopian highland and lowland male chicken

Temperature stress impacts both welfare and productivity of livestock. Global warming is expected to increase the impact, especially in tropical areas. We investigated the biological mechanisms regulated by temperature stress due to the circadian temperature cycle in temperature adapted and non-adapted chicken under tropical conditions. We studied transcriptome profiles of heart, breast muscle, and spleen tissues of Ethiopian lowland chicken adapted to high circadian temperatures and non-adapted Ethiopian highland chicken under lowland conditions at three points during the day: morning, noon, and evening. Functional annotations and network analyses of genes differentially expressed among the time points of the day indicate major differences in the reactions of the tissues to increasing and decreasing temperatures, and also the two chickens lines differ. However, epigenetic changes of chromatin methylation and histone (de)acetylation seemed to be central regulatory mechanisms in all tissues in both chicken lines. Finally, all tissues showed differentially expressed genes between morning and evening times indicating biological mechanisms that need to change during the night to reach morning levels again the next day.</p